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View Full Version : LT-1 owners: There is a fix for cooling system issues


gibbons
07-31-2009, 04:52 PM
Hi All, I am new to this forum, but have lots of MC hours on our 94 205 with an LT-1. It started life with all kinds of cooling system issues, I am surprised I didn't melt it down before I got a handle on things. Way back when, I discovered a fatal flaw in how the engine was applied. I alerted Indmar and MasterCraft, they sent out a service bulletin incorporating the fix I came up with.

With my fix, the engine temp stays absolutely constant within a few degrees, from idle to full throttle. If there is residual interest in this motor or the fix, let me know, and I will take time top post pictures and a scan of the MasterCraft service bulletin (to prove that my info is good). I also have a trick for the heater source and return that I can't take credit for, but perfects the heater. I can share that one, too.

Reply to my post if interested!

D3skier
07-31-2009, 05:08 PM
to start off you might want to become a full member of team talk before you go "claiming" you came up with "the fix"

SkiDog
07-31-2009, 05:18 PM
to start off you might want to become a full member of team talk before you go "claiming" you came up with "the fix"

I don't recall having seen ANY threads concerning this motor and overheating problems. But I was wrong once before too, so I dunno>!:D

flipper
07-31-2009, 05:32 PM
Was the trick to change the impeller?

brat
07-31-2009, 06:08 PM
I would certainly like to see the service bulletin, post it up.

Ben
07-31-2009, 06:13 PM
+1 for wanting to see it. I've got the same boat. Please become a member and give the description / pictures.

I've had no real issues, but I'd like to add a heater someday, and the temp always seems shaky the 1st few outings of the year, maybe the thermostats just need to get used to working again...

flya750
07-31-2009, 06:18 PM
I have a 1997 LT1 .... 730 hours ... no over heating problems?

The heater doesn't stay warm unless the boat is running @ speed. Do you have a fix for that?

gibbons
07-31-2009, 07:53 PM
First off, I just posted my first post today, to see if I had any options for fixing a seam in my observer seat. I started reading some unrelated posts and thought maybe I could be a positive contributor. I don't even know how to sign up to be a full team member. Is ignorant instant sarcasm and skepticism how some of this group treats someone offering a great tip? Gee, maybe I don't want to sign up...

Anyone who doesn't know that LT-1's doesn't know what they don't know. The LT-1 has aluminum heads, reverse cooling, and a cam driven water pump (you knew that, right?). That caused a big problem. It was addressed in the June 1996 Service Bulletin that was generated after my disclosure to MasterCraft and Indmar. Does anyone remember MasterCraft's Nathan Long? I sent him the fix initially. He got Indmar's Alan Tehan in touch with me. Is he still around? He flew in from Indiana and rode around in my boat. He also did some altitude tweaking on my EFI calibrations. Still thinking I'm making something up? I am, after all, just a dumb mechanical engineer.

The overheating problem has to do with aerated intake water and steam in the heads. Wanna know more? Tell me how to fully sign up. If your boat doesn't do it, it may have been built after the bulletin, and had the modification done at the factory.

Yes, I have a fix that will make the heater work full temperature at idle. Absolutely, positively. You will love it. It's a simple plumbing routing. We used to ski mostly in the off season, which meant the water was usually 50 degrees and below. I have wakeboarded while it was snowing, one day we waterskied in the morning and snow skied that afternoon. My family was on the evening news weather for being crazy. Anyway, when it's that cold, you want a heater working full time. Yes, I can show that trick too. But again, I didn't come up with that one. Another LT-1 owner discovered the right plumbing to do it. I showed him how to keep from cooking his motor (the service bulletin topic).

So, if you want more, help me out to get fully registered or whatever. But please knock off with the doubt.

SkiDog
07-31-2009, 08:55 PM
First off, I just posted my first post today, to see if I had any options for fixing a seam in my observer seat. I started reading some unrelated posts and thought maybe I could be a positive contributor. I don't even know how to sign up to be a full team member. Is ignorant instant sarcasm and skepticism how some of this group treats someone offering a great tip? Gee, maybe I don't want to sign up...

Anyone who doesn't know that LT-1's doesn't know what they don't know. The LT-1 has aluminum heads, reverse cooling, and a cam driven water pump (you knew that, right?). That caused a big problem. It was addressed in the June 1996 Service Bulletin that was generated after my disclosure to MasterCraft and Indmar. Does anyone remember MasterCraft's Nathan Long? I sent him the fix initially. He got Indmar's Alan Tehan in touch with me. Is he still around? He flew in from Indiana and rode around in my boat. He also did some altitude tweaking on my EFI calibrations. Still thinking I'm making something up? I am, after all, just a dumb mechanical engineer.

The overheating problem has to do with aerated intake water and steam in the heads. Wanna know more? Tell me how to fully sign up. If your boat doesn't do it, it may have been built after the bulletin, and had the modification done at the factory.

Yes, I have a fix that will make the heater work full temperature at idle. Absolutely, positively. You will love it. It's a simple plumbing routing. We used to ski mostly in the off season, which meant the water was usually 50 degrees and below. I have wakeboarded while it was snowing, one day we waterskied in the morning and snow skied that afternoon. My family was on the evening news weather for being crazy. Anyway, when it's that cold, you want a heater working full time. Yes, I can show that trick too. But again, I didn't come up with that one. Another LT-1 owner discovered the right plumbing to do it. I showed him how to keep from cooking his motor (the service bulletin topic).

So, if you want more, help me out to get fully registered or whatever. But please knock off with the doubt.


First of all, we all on here like to have a little fun with EVERYBODY that shows up here. I didn't see ANYBODY doubt what you said, they just said they'd like to see MORE. personally, I don't have an LT-1, so no, I wouldn't know that it has aluminum heads, reverse cooling , and a cam driven water pump. So I've got NO dog in that fight.
Secondly, IF you are a mechanical engineer, you should be able to figure out a simple process for signing up on here. Its NOT hard.
We welcome EVERYBODY, (with the exception of a select few)( and you're NOT in that select few, BTW) to this board! I suggest that you thicken up your skin just a wee bit, join, and have fun like the rest of us do on here. We always like to hear from people that know what they are talking about, even IF we do rag you a little bit.
BTW, what year is your boat? Skidog

JimN
07-31-2009, 08:59 PM
First off, I just posted my first post today, to see if I had any options for fixing a seam in my observer seat. I started reading some unrelated posts and thought maybe I could be a positive contributor. I don't even know how to sign up to be a full team member. Is ignorant instant sarcasm and skepticism how some of this group treats someone offering a great tip? Gee, maybe I don't want to sign up...

Anyone who doesn't know that LT-1's doesn't know what they don't know. The LT-1 has aluminum heads, reverse cooling, and a cam driven water pump (you knew that, right?). That caused a big problem. It was addressed in the June 1996 Service Bulletin that was generated after my disclosure to MasterCraft and Indmar. Does anyone remember MasterCraft's Nathan Long? I sent him the fix initially. He got Indmar's Alan Tehan in touch with me. Is he still around? He flew in from Indiana and rode around in my boat. He also did some altitude tweaking on my EFI calibrations. Still thinking I'm making something up? I am, after all, just a dumb mechanical engineer.

The overheating problem has to do with aerated intake water and steam in the heads. Wanna know more? Tell me how to fully sign up. If your boat doesn't do it, it may have been built after the bulletin, and had the modification done at the factory.

Yes, I have a fix that will make the heater work full temperature at idle. Absolutely, positively. You will love it. It's a simple plumbing routing. We used to ski mostly in the off season, which meant the water was usually 50 degrees and below. I have wakeboarded while it was snowing, one day we waterskied in the morning and snow skied that afternoon. My family was on the evening news weather for being crazy. Anyway, when it's that cold, you want a heater working full time. Yes, I can show that trick too. But again, I didn't come up with that one. Another LT-1 owner discovered the right plumbing to do it. I showed him how to keep from cooking his motor (the service bulletin topic).

So, if you want more, help me out to get fully registered or whatever. But please knock off with the doubt.

I was an MC tech starting in late '97 and we had all of the bulletins AFAIK, which I read. I also went to MC training in March of '98. Care to PM me so I know which bulletin it was?

I remember Nathan and it was Alan who developed the training courses, among other things. If it was the bleeder lines or the holes in the thermostat, they were in place before I started working on these.

Welcome to Team MasterCraft but,

You have basically walked into a room full of people who were in the middle of several conversations, without bothering to introduce yourself before saying that you're not sure you like being here. This is your second post, right? No offense, but it was kind of an awkward entry. I don't think anyone will have a problem with knowing about your fix for the LT-1 but to come in, claim that you fixed it without providing anything to support it doesn't really make it so, even if it's absolutely true. I don't know why you would expect total strangers to believe what anyone says just because they say it's true. I doubt you would do this, especially considering your field. You work in a field that would never accept someone's word for any kind of claim without proof, right?

It would be better to get to know the people here before you tell them to not doubt your qualifications and FYI, you're not the only engineer here. We have all kinds of people, from all walks of life and while we may toss odd comments around, the vast majority are good natured. Sure, we have some who don't get along but if we all sat here singing Kumbaya, it would be a really boring place, IMO.

BTW- it's not that hard to look around for the buttons for registration. Here's a link- it's in hte middle of the top gray bar:
http://www.mastercraft.com/teamtalk/portal.php

gibbons
07-31-2009, 09:03 PM
I said I'm a mechanical engineer, not a software engineer :) Heck, if I can post, am I not signed up? What else do I do?

I just spent an hour taking pictures, adding text, and re-sizing them. They are ready to post as soon as I am "signed up". I promise, someone here, if they will listen, will be elated with the changes.

A few notes:

flya750- if your boat is a '97, it probably as (better have) the cooling system changes incorporated from the factory. Hence, no cooling problems.

Also, to show that I am a tinkerer who comes up with goofball stuff that works, here is a link to a Volvo XC70 (AWD station wagons) forum where I defined how to easily change "good for life" automatic transmission fluid. The forum moderator thought it was good enough to put in a permanant "sticky" at the top of the forum http://www.volvoxc.com/forums/showthread.php?t=12169

JimN
07-31-2009, 09:13 PM
I said I'm a mechanical engineer, not a software engineer :) Heck, if I can post, am I not signed up? What else do I do?

If you're an ME and you can't navigate here, you either still use a slide rule or just don't think computers are going to catch on.:D

I posted a link but I don't have your personal info so,.....

Remember, the head of IBM asked why anyone would want a personal computer, in1959 and in 1899, the head of the US patent office said "Everything that can be invented, has been".

gibbons
07-31-2009, 09:14 PM
JimN- Yup, moving the bleeders from the rears of the heads (where they work on cars) to the fronts of the heads. MasterCraft, Indmar, and GM Powertrain all missed that. I guess it's like you can't proof read your own documents effectively, it was obvious to me. It wasn't rocket science, but I caught it. The Service Bulleting was MC96-001, I have a copy that Nathan sent me when it came out. I will post the pics so everyone can check their LT-1's as soon as I am official.

SkiDog
07-31-2009, 09:15 PM
Go up to the top right corner of the page , and find the 'log in - register' tab, click on it and follow the directions. Should be cut & dried.

JimN
07-31-2009, 09:19 PM
Where were you when they still offered that motor and why didn't you look for this forum?

Seriously, I don't remember seeing very many with repeated overheating issues, mainly because they had either been fixed before I started or because MC/Indmar had already made the changes. If you are/were in Colorado, he did mention going out there for some high altitude testing, but they were doing that anyway. Seeing as it has been 11 years since I went the first time, I'm going to say that I don't remember every detail of every day in class, but I do remember most of it.

gibbons
07-31-2009, 09:22 PM
I did that... that box is currently showing "Logged in" in green. If I wouldn't have registered as "gibbons", I couldn't have posted. It required all my personal info, etc. Is there a daily batch update that needs to come up before I show up as a member to everyone else?

JimN
07-31-2009, 09:27 PM
JimN- Yup, moving the bleeders from the rears of the heads (where they work on cars) to the fronts of the heads. MasterCraft, Indmar, and GM Powertrain all missed that. I guess it's like you can't proof read your own documents effectively, it was obvious to me. It wasn't rocket science, but I caught it. The Service Bulleting was MC96-001, I have a copy that Nathan sent me when it came out. I will post the pics so everyone can check their LT-1's as soon as I am official.

OK, but the motor in the boats is at a different angle, too and that would make a big difference. The cars have a bleeder screw on the highest point of the cooling system and the boats can't have that luxury.

Stinkin' gravity!

Since that was the first bulletin of '96 (we had a binder with all of them), you probably came up with it in the middle of '95, right? I can't see them going out and acquiring data for normal performance in extremely cold weather, regardless of whether a few people were still boating. Cool, but not extremely cold but I know they could have done a custom program. Setting the fuel tables in extremely hot weather doesn't work well, either. There was one year Alan was pressured by someone (I don't remember if it was Indmar or MC) but they wanted the programs before they were ready and it resulted in cold start issues. Late '98, I think.

Ski-me
07-31-2009, 09:30 PM
I have heard that once in awhile someone registers and it doesn't click all the way in. The new member can see he is logged in but for some reason, the posts still show up as "guest". Hopefully a moderator can check it out for you.....

And yes, I have an LT1 and know that it's reverse cooling and aluminum heads. I also would like to see what you have available. I'm also a Civil Engineer.:cool:

gibbons
08-01-2009, 12:38 AM
OK, I will assume I am "in" and see if I can get pics to post. Attached (hopefully) is page 1 of the service bulletin. I messed around with the overheating during 95, got it zeroed in and submitted to MC in early 96.

In a car application, there is a tube that connects to a port on the rear of each head with big "banjo bolts". The tube hooks up to the cooling system to purge any bubbles that may get in the head. Once the bubbles in a car are gone, they're gone since it's a closed system. In the boat application, GM Powertrain and Indmar didn't think that one through, they left the tube on the back of the heads. Since the motor is at a large angle, and even larger when the boat is on plane, there is no way that bubbles can exit efficiently. They naturally float upwards and can fill the heads so water can't circulate. At higher RPMS, they can get scavenged out, but at lower speeds like wakeboarding, they can fill the heads. When that happens, there is no water cooling, and things get too hot really quickly. The bubbles get sucked into the cooling system through the hull intake when crossing frothy water, bouncing over rollers, etc. Heat soak can create bubbles when the engine temp goes over 212, so you can fill the heads with steam air when the motor is first turned off. Remember, car systems are pressurized up to 16psi and have antifreeze, which raises the coolant boiling point, so they don't have this problem.

The heads are symetric, they can be installed on either side of the engine. So they have port holes on the fronts and backs. The fronts, the best place to purge bubbles, have pipe plugs in them. I thought the rear porting was useless, so I removed the plugs and tube and swapped them front-to-back. The tube doesn't fit the front because of the water pump, so I spent quite a bit of time hand bending it to fit. But it can be done. The service bulletin page 2 has a list of threaded bushings, elbows, barbs, etc to pick up at a hardware store to do the job, but that would look cobby. They should have just said to bite the bullet and carefully bend the tube. Once the tube is hooked up to the front, take it to one of the exhaust manifolds like it was when in the back.

To make sure I wasn't introducing any bubbles into the system, I fabricated a bubble catcher from a soldered copper Tee, cap, and brass nipple. It installs before the thermostat housing. Any water entering into housing has to pass by, and the bubbles will rise into the cap and get purged into the other exhaust manifold. MasterCraft didn't see the need for that extra piece, but I did just for piece of mind.

After I did this, I never had another temperature spike with the accompanying RPM reduction. My temperature has been rock steady at 170 degrees. That's the topic of another post upcoming in this thread.

mbpd312
08-01-2009, 12:49 AM
I give up!!

gibbons
08-01-2009, 12:57 AM
I mentioned above that my motor runs 170 degrees steady. The next trick is to plumb the heater right. You gotta get the right source point and return point. This was devised by a guy a met, not me. He was crossing a lake in a bad storm, at a lower speed to keep his bow up. His heads filled with air, and his boat went into reduced RPM mode, which dropped his bow. He almost got swamped. He spent a lot of time with clear tubing on his cooling system to determine flows and what was needed. It works.

The right point for the source is in the circulation pump, cuz it has good pressure and the hottest water. You remove the Engine Coolant Temperature sensor from the pump housing, and install a Tee. The sensor goes back into the Tee, and a hose barb goes in the other leg as shown below. The return is into the port on top of the water pump, as shown in a picture in a post above. This works out great, because it keeps water flowing through the heater at any engine speed, and keeps water flowing consistantly past the ECT. If you do this, your heater will put out full heat at idle. Promise. It's great!

I like my motors to run a little hotter, they run these motors 220 in cars. 160 didn't "feel" intuitively right. I tried a 180, but that was too hot, I was getting too much heat soak when it turned off. It would go into reduce RPM mode. I needed a 170 degree stat. I like the Stant brand design, they seem more linear than the Robertshaw style that comes stock. I called Stant and drilled around until I got an engineer in the test lab. He actually made me 2 custom 170 stats. I installed one and keep the other for a future spare. Rats, that was years ago, I doubt I could repeat that event. I have scoped the Summit Racing and Jegs sites (muscle/race car guys) looking for an off the shelf 170, I don't believe one exists. If you ever see one, buy it for your newly plumbed LT-1.

flya750
08-01-2009, 02:12 AM
A few notes:

flya750- if your boat is a '97, it probably as (better have) the cooling system changes incorporated from the factory. Hence, no cooling problems.


Gibbons,

I will check my '97 LT1.

Thanks for the heater fix info. I will look into it. The girls I ski with in the spring and fall will love the modification. ;)

Welcome to the forum. I can't believe this is your first time visiting since you've been a MC nut for awhile now.

Anyway.. Welcome!

Kevin@MWMC
08-01-2009, 02:51 AM
Welcome to the forum Gibbons, and here is the way to fix your account.

http://www.mastercraft.com/teamtalk/showthread.php?t=26931

Same thing happened to me when I first signed up......

gibbons
08-02-2009, 02:21 PM
By the way, when (if) you winterize your boat, it's a good idea to back flush your heater. In the case of my set up, I remove the hose from the water pump and route it through the bilge hole (so the yuck goes right out). Then I connect a strong water pressure source to the return hose on top of the thermostat housing. Even running a sea water strainer, it's amazing the amount of junk that comes out. That includes rust scale from the engine block...

TripleThreat
08-02-2009, 02:55 PM
gibbons,

There was some kind of issue when I registered also and at first I showed up as a guest. It all had something to do with some changes that were made to the forum a while back. If you send an email to this address and let Phil know you are having a problem, he will take care of getting it fixed for you.

phil.walker@mastercraft.com

Oh, welcome to the forum...

Jeff

edit... just noticed that Goliath pointed you to the thread with the contact info for Phil... Oh well...

redlightning
08-09-2009, 11:47 PM
How does this apply to the 225 vrs? This motor is inverted. I have been trying to work out a heating problem all summer. I finally removed the t-stat to keep the motor cool until i figure out what is up. I notice the problem when i run the motor rpm's above 3200 rpm or so.

captain planet
08-10-2009, 09:03 AM
I have been watching this thread and there are 2 things about which I am curious. First, my engine came with a 143 degree thermostat and runs at that temperature. Never had a problem with the lower temp, however my LT-1 isn't your typical LT-1 as it is rated at 350 HP because it is an Anniversary boat. Second, I have a heater and it does not run hot at idle, only at about 1000 rpms or so. Do you have any other pictures of where to replumb the heater? I don't use mine very often, however I had it on Saturday and going through a couple no-wake zones it cooled off.

gibbons
08-10-2009, 06:29 PM
The 143 is the stat in the triangular "mixing" housing. It's job is to take motor warmed water and mix it with cold lake water, so there isn't so much of a thermal shock at the block's thermostat. The thermostat for the motor is under the aircleaner, under the filler neck. It should be 160 degrees. They used Robertshaw brand stock, I like Stants. That's the one that I got a custom 170 made, and it works great.

If your motor is running 143, that's too cold. The tolerances and clearances between components were designed for a higher temp, so everything has to thermal expand to fit right. That's the whole point behind "warming up" an engine. Plus will never burn off moisture and diluted fuel.

Back to heaters.... I'm not sure what my pictures aren't showing(?) The water comes out of the front of the circulation pump at the added Tee and returns at the nipple on the top of the pump. Ask questions....

And yes, I promise you will get full heat at idle. If you get the right temp range stat in there so it runs more like 160, all the better!

Jorski
08-10-2009, 09:00 PM
CP,

Early LT-1's often had overheat issues. Sometimes owners (incorrectly) solved the probelm by removing the upper (163 degree) t-stat. That maybe the case with yours - it was with mine when I bought my 1993 used.

I would doubt that yours should be running at that cold of a temperature since the in cars they run at 180 degrees.

flya750
08-10-2009, 10:01 PM
Gibbons...

You are Da Man! and a refreshing addition to this forum!!!

Keep the knowledge coming!!!!

THANKS!!

captain planet
08-11-2009, 08:49 AM
CP,

Early LT-1's often had overheat issues. Sometimes owners (incorrectly) solved the probelm by removing the upper (163 degree) t-stat. That maybe the case with yours - it was with mine when I bought my 1993 used.

I would doubt that yours should be running at that cold of a temperature since the in cars they run at 180 degrees.

I would add that my LT-1 is not an "early" one. In fact it was the last year they used the engine because in 1999 they went to the LTR. Also, my engine had some work done on it by Indmar after the boat was purchased. The details I can't get into, but my LT-1 is modified to get 350 hp because it is an Anniversary boat. The engine in my boat was kind of a guinea pig for Indmar to play with prior to my purchase. I would think these kind of things would have been addressed.

Gibbons, I've never pulled the t-stat but I know it has a 143 degree stat in it. The instructions with the heater said to install a 160 degree for more heat if you have the LT-1, however when it is warm it throws more than enough heat...just doesn't at idle. I will print off your pictures and take them with me to the lake this weekend and see where you are talking about hooking up the hoses. Right now my heater is plumbed off the top of a housing in front of the motor (can't remember the name of it right now) and off the starboard side under the air intake/flame arrester. Those were the instructions that came with the heater. I'll also take a couple of pictures of where it is hooked up for you to see.

Thanks

gibbons
08-11-2009, 09:52 AM
As I recall the 350 hp motor just had rocker arms with a higher ratio, like 1.6 instead of 1.5, and different firmware in the ECM. So it should be pretty much the same as the other motors out there. My boat came with 310 hp, and a couple of years they released a different ECM that was actually different hardware with different firmware. They claimed it was 328 hp. I got one of those ECMs, ran it, couldn't really tell a difference other than my spark plugs were really lean looking. I put my 310 ECM back in. There is a lot of hokus pocus going on.

I shared my tinkering with the air purge lines with MasterCraft. The guy who came up with the hearter plumbing never did, he was at war with MC. So you won't see it documented anywhere.

Dave2302
08-11-2009, 10:37 AM
Hi,

Welcome Gibbons.

Nice piece of work, and I'm surprised MC / Indmar didn't realise what was happening, LOL actually no I'm not surpised. I've built several modded 400 cube motors some in marine applications and these have a steam issue, because the bigger bore block has no waterway between the cylinders. The fix here was to drill holes in the heads and gaskets when fitting ally or non 400ci heads, to allow the steam to rise.

Also, regards the heater fix, over here in UK lots of guys run tournament ski boats on LPG as petrol (gasoline) is so expensive here. One of the problems I came across when we first started installing LPG on marine (raw water cooled engines) was a lack of hot water to heat the vaporizer unit at low rpms. They will freeze if left Idling or run below about 1800 rpm for more than a couple of minutes. Also the heaters are useless at low rpm, so I came up with the following fix:-

Fit a smaller diameter water circulation pump pulley and shorter drive belt, thus spinning the circulation pump faster, result hot heater and no LPG vapourizer freezing at lower rpms. It has no ill effects on high rpm cooling, (one of my smallblock marine motors used to run up to 7000 rpm regularly with no problems. The pulley I use is a regular GM / Chevy part, (sorry guys can't remember the part no) but from memory it is 5 1/2 " dia as opposed to the standard 7 " dia pulley fitted on most marine GM's.
Obviously this won't work with the cam driven water pump LT1's but works on the regular small and big block motors.

Hope this helps someone,

Regards Dave.

Jorski
08-11-2009, 04:05 PM
CP,

I am curious about your engine. Does it have different heads and/or pistons?

captain planet
08-11-2009, 04:08 PM
CP,

I am curious about your engine. Does it have different heads and/or pistons?

Heads and Pistons are the same, I was told the cam and rocker arms are different to get the 15 to 20 additional HP out of the engine vs. regular LT-1.

captain planet
08-11-2009, 04:09 PM
As I recall the 350 hp motor just had rocker arms with a higher ratio, like 1.6 instead of 1.5, and different firmware in the ECM. So it should be pretty much the same as the other motors out there. My boat came with 310 hp, and a couple of years they released a different ECM that was actually different hardware with different firmware. They claimed it was 328 hp. I got one of those ECMs, ran it, couldn't really tell a difference other than my spark plugs were really lean looking. I put my 310 ECM back in. There is a lot of hokus pocus going on.

I shared my tinkering with the air purge lines with MasterCraft. The guy who came up with the hearter plumbing never did, he was at war with MC. So you won't see it documented anywhere.

THis is where my boat was the guinea pig. They had to play around with the calibration to make it run right to get 350 HP.

Craig
08-11-2009, 04:17 PM
I have been watching this thread and there are 2 things about which I am curious. First, my engine came with a 143 degree thermostat and runs at that temperature. Never had a problem with the lower temp, however my LT-1 isn't your typical LT-1 as it is rated at 350 HP because it is an Anniversary boat. Second, I have a heater and it does not run hot at idle, only at about 1000 rpms or so. Do you have any other pictures of where to replumb the heater? I don't use mine very often, however I had it on Saturday and going through a couple no-wake zones it cooled off.

My LT-1 also used to run at 143-ish, I thought this was normal. Some other threads caused me to investigate because it seemed like it should be running around 160.

I took the upper housing off to check the 160 t-stat and there was nothing there. I got a new drilled 160 t-stat from skidim and it has been a solid 160 ever sense. It does move around a bit more than when it was running at 143 but not enough to make me worry.

It doesn't sound like your cooling system is any different than most LT-1's so I suspect someone may have taken out our 160 t-stat as well. Maybe not, but it takes about 5 minutes to check. I have noticed less gas smell in the exhaust since I made the change.

captain planet
08-11-2009, 04:30 PM
:confused: After reading all this I'm in a mental conundrum. "If it ain't broke, don't fix it" resonates with me. My boat ain't broke so I really don't want to fix it, however if I can get a little more efficiency out of it and have heat all the time when I want it might be worth it. I just REALLY don't want to go messing with the temp of the engine because of the alum heads. I'll check to see if I have a thermostat or if it has been removed......and hope I don't booger up the gasket when I take it apart. :mad::( Maybe I'll do it after I put it away for the season so if I do mess up the gasket I won't be grounded.

Jorski
08-11-2009, 05:39 PM
Hey CP,

I asked about the heads and the pistons because the temperature at which the engine runs is the range at which the various components, such as a cast iron block and aluminum heads fit together properly. Too cold and the tolerances would be out of spec, same with too hot.

This why so many here questioned the 143 enging temp. One would assume that if you have the same components, the same temperature would be required.

The upper t-stat (163 degree drilled) doesn't use a gasket, it comes with the rubber ring that fits around the t-stat itself, and that serves as the "gasket". Make sure you use the correct one from Mastercraft or Skidim etc.

If you do decide to add the upper t-stat, you should use less fuel as a bonus. Maybe a call to Indmar would be good idea.

gibbons
08-11-2009, 08:25 PM
CP, I hear ya on "if it ain't broke, don't fix it". But if it isn't optimized, and can be EASILY improved, do fix it!

As I mentioned way up in the thread, they ran these motors at 220 in cars (but with the advantage of a pressurized system with coolant additive). If you are at 143, the EFI calibration will probably make it run rich since it thinks it's still warming up. Mine ran great with a 180 stat, but when I shut it down, it would heat soak into the reduced RPM mode and run goofy when started again until the cooling system had purged the super hot water. I settled on my special made 170 stat.

Most LT-1 heaters I saw took water off the port side block drain, and returned into the nipple on the starboard side of the circulation pump (l return mine to that nipple as shown in my picture). That's where they told me to install mine initially. That fitting on the block is what, 1/8 NPT? The hole is tiny, even with good pressure, it can't flow much water (heat). The fitting on the circulation pump is 3/8 NPT, lots/lots bigger for mega flow (mega heat).

CP, from what I remember, they didn't change the cam, just the rocker arms. Increasing the rocker arm ratio increases the valve lift, which increases duration, which is like changing a cam.

JimN
08-11-2009, 09:11 PM
CP, I hear ya on "if it ain't broke, don't fix it". But if it isn't optimized, and can be EASILY improved, do fix it!

As I mentioned way up in the thread, they ran these motors at 220 in cars (but with the advantage of a pressurized system with coolant additive). If you are at 143, the EFI calibration will probably make it run rich since it thinks it's still warming up. Mine ran great with a 180 stat, but when I shut it down, it would heat soak into the reduced RPM mode and run goofy when started again until the cooling system had purged the super hot water. I settled on my special made 170 stat.

Most LT-1 heaters I saw took water off the port side block drain, and returned into the nipple on the starboard side of the circulation pump (l return mine to that nipple as shown in my picture). That's where they told me to install mine initially. That fitting on the block is what, 1/8 NPT? The hole is tiny, even with good pressure, it can't flow much water (heat). The fitting on the circulation pump is 3/8 NPT, lots/lots bigger for mega flow (mega heat).

CP, from what I remember, they didn't change the cam, just the rocker arms. Increasing the rocker arm ratio increases the valve lift, which increases duration, which is like changing a cam.

If they used a 143 degree thermostat in development, they would have run it only as rich as needed for normal operation and they can tell it whatever they want as far as normal operating temperature. You could have had the ECM recalibrated later for a higher temperature at startup because they did have some issues in AZ, TZ and Southern California with the ECM registering overheat when it was only heat soak induced.

Why did you buy another ECM instead of having yours recalibrated- just to be able to go back to the other more easily?

gibbons
08-11-2009, 09:18 PM
I didn't buy the new ECM. I know some don't believe me, but I was working with Tehan a lot. When he came to see my motor, he did some programming on my MEFI I ECM. Later, when the MEFI II came out (remember, they had the smaller housing), he sent me one for grins. That ECM had the 328hp calibration loaded in it, it's the cal that I thought was too lean. So I put my old one 310/MEFI I back in and put the II in a sealed bag in the boat for a spare.

JimN, you're fun, you remember this old stuff!

JimN
08-11-2009, 09:23 PM
I didn't buy the new ECM. I know some don't believe me, but I was working with Tehan a lot. When he came to see my motor, he did some programming on my MEFI I ECM. Later, when the MEFI II came out (remember, they had the smaller housing), he sent me one for grins. That ECM had the 328hp calibration loaded in it, it's the cal that I thought was too lean. So I put my old one 310/MEFI I back in and put the II in a sealed bag in the boat for a spare.

JimN, you're fun, you remember this old stuff!

I was just wondering. If I wanted to verify this, I'd just call him. He does a lot of things "just for grins". Been to his website lately?

gibbons
08-11-2009, 10:23 PM
I've been content with my boat for so long that I haven't even thought about him or MC. He has a website? The last thing I remember about my following Indmar and Tehan was when they started selling to Malibu. What is Tehan's site?

JimN
08-11-2009, 10:59 PM
I've been content with my boat for so long that I haven't even thought about him or MC. He has a website? The last thing I remember about my following Indmar and Tehan was when they started selling to Malibu. What is Tehan's site?

I'd prefer to PM the address. Why are you still shown as a guest? Others have only one post and have full registration.

redlightning
08-12-2009, 01:38 AM
I am still confused about the cooling in my boat. I have a 94 225vrs. vdrive, motor inverted compared to some of your boats. Early motor i guess. Most of the cooling system i completely understand and have thoroughly checked out but still have the motor heating up at higher rpms. New tstats, tried two different impellars. Started replacing hoses even though none are leaking. trasmission cooler is clear, intake at the hull is clear.

The description of the problem associated with the cooling modifications sounds very much like the problem I am having. I have a single connection from the back of the passenger side head to the top of the exhaust manifold. The drivers side has no hose connected to the head. I have a hose from the tstat housing to the top of the drivers side exhaust manifold. The hand drawing floating around here on the site is exactly how my motor is plumbed. Was there some modification to this arrangement that solves this problem?

gibbons
08-12-2009, 09:55 AM
I haven't been around long enough to see a hand drawing, can you post a link to it? And I can't remember the VRS configuration, but the tail of the motor is down, the air cleaner is up, right? Look really close, that connection from the head to the exhaust should be a two tube "banjo bolt", with a tube on one side to the exhaust and the other tube to a one-tube banjo bolt at a similar place on the other head. Can you post a pic?

redlightning
08-12-2009, 03:12 PM
Thanks! I feel stupid now. I did a search for LT-1 and looked at some parts and i see now that it is a crossover tube that ties together the two heads. Sorry for my ignorance everyone. I didnt see it. It is making much more sense now.

So... this fix is to move this crossover tube to the front of the motor instead of the back of the motor. This has clearly not been done to my boat. I will check the stance of the motor but i think you are correct that the front is higher even inverted.

JLeuck64
08-12-2009, 07:02 PM
I haven't been around long enough to see a hand drawing, can you post a link to it? And I can't remember the VRS configuration, but the tail of the motor is down, the air cleaner is up, right? Look really close, that connection from the head to the exhaust should be a two tube "banjo bolt", with a tube on one side to the exhaust and the other tube to a one-tube banjo bolt at a similar place on the other head. Can you post a pic?

Wow, I go on vacation for a few weeks and an interesting topic finally surfaces...

Here is the drawing someone uploaded to this website before. I don't remember who but would like to give that person their due credit.

JLeuck64
08-12-2009, 07:12 PM
:confused: After reading all this I'm in a mental conundrum. "If it ain't broke, don't fix it" resonates with me. My boat ain't broke so I really don't want to fix it, however if I can get a little more efficiency out of it and have heat all the time when I want it might be worth it. I just REALLY don't want to go messing with the temp of the engine because of the alum heads. I'll check to see if I have a thermostat or if it has been removed......and hope I don't booger up the gasket when I take it apart. :mad::( Maybe I'll do it after I put it away for the season so if I do mess up the gasket I won't be grounded.

Tough call, I had the 160 degree T-stat installed along with my heater. It also puts out decent heat above idle. Don't try and re-use the gasket if you look in to yours. Just make a new one. My temp doesn't really spike very much at all when shutting down the engine for a few minutes. My LT-1 is the same as yours and the cross-over pipe was updated before they painted the engine BLUE!

I even added the Y-pipe that SkiDim sells to increase flow through the heater at idle but have not really noticed a difference... To much time elapsed before I started using the heater again.

Gibbons, your custom tee behind the coolant temp sensor looks interesting... might have to fab one of my own this fall!

gibbons
08-12-2009, 08:33 PM
I will beat a dead horse.. if you re-route your heater as shown in my picture, you will get full, hot heat at 650 rpm. It's the only way we survived years of skiing in the spring and fall with air temps in the 30's and 40's. I have ridden a wakeboard while it was snowing...

Anyway, that pdf shows the stock plumbing configuration. Note the "bleed tube"... that doesn't work that well with a boat. The hole is offset to the back, and the hole if the fitting is pretty tiny to catch a big bubble. That's why I capped mine off, and fabricated that big Tee with the bleed tube on top of it. I am pretty sure I am catching all the bubbles with that unit.

Even if your cooling system is working right, you will get heat soak spikes. That happens with any engine, the big block in my Chevelle runs 195 but soaks to 230 when shut off. My LT-1 goes to 100 or so, but I am running it a 170. No problem, I am below the level that the ECM freaks out. What my head plumbing gig does is keep the heads from filling with air so they spike while running.

Jorski
08-17-2009, 01:56 PM
Hey Gibbons,

Thank you for pointiong all of this out.

Turns out my crossover tube is on the back of my block. So, I am going to try and reconfigure things this weekend.

Is there any kind O-ring or gasket under the banjo bolts? Or does it seal in the threads?

redlightning
08-21-2009, 05:52 PM
Gibbons,

Any chance you could post the entire TSB? I would like to see the parts list if you have it.

Thanks

gibbons
08-24-2009, 01:12 AM
Sorry, been gone playing with the Chevelle and bikes for a while.... I will see if I have the subsequent pages to the bulletin. It was just a bunch of bushings, barbs, and stuff like that. It's intuitive if you look at the situation. Banjo bolts have recessed o-rings in them that self seal.

redlightning
08-25-2009, 01:25 AM
I made the swap. I ordered a new crossover tube from GM dealer. A little bending and it fits just fine. Pretty long tube, so i cut it off about 6 in from the fitting. I tied it into the drivers side exhaust manifold and swapped the hose coming from the t-stat housing over to the pass side exhaust manifold.

I do believe that this has made a difference. Temp is much more stable. I am still seeing a rise in temp when i run 3200+ rpm for 10 - 15 min steady. It creaps very very slowly up. Now does not seem to go past 185. This is the only time i see a temp issue. I can pull skiers and wakeboarders all day, starting and stopping.

Once it heats up to 185, it does not come down just slowing down to 2k rpm. It takes it a bit to start cooling down, even in neutral reving the motor a bit.

I have replaced the raw water impeller, hoses and t-stats. Looked for blockage in the system with no luck. The only things i have not replaced are the circulation pump, the molded hoses and the temp sensor. It does not seem to be erratic enough to be a temp sensor. Circulation pump? Could i have a hose collapsing? Any Ideas?

gibbons
08-25-2009, 07:48 PM
What value of thermostats did you put in? 185 sounds quite high, especially if you used a 160 in the circulation pump (on the motor). My custom 170 stats give me 170, when I tried a 180, I got about 185. That was too high, it allowed it to heat soak high enough to cause reduced RPM function.

The stock thermostats were Robertshaw brand, they look like they have a big brass cup off of the bottom. As I mentioned, I like Stant Superstats. They are stainless steel, and have larger stronger "thermal motors" and return springs. I went through all kinds of feel-good testing, and found the stove top test to be quite revealing. The Robertshaw seemed quite notchy in operation, and seemed like it wanted to search for an all or nothing opening operation. Stants open quite smoothly and very linear. I think they contribute to temperature stability.

Another thing that leads to stability is re-routing the heater lines like I my pictures showed. I'm not so sure the mixing stat does a great job as configured on an LT-1, I get plenty cool water into the top Tstat housing. Rerouting the heater lines as shown puts hot water back into the circulation pump and seems to stabilize the temp more, vs having such a temperature gradient between the hose into the Tstat housing and the circulation pump.

The circulation pumps are quite robust, but it could be that, I guess. There's nothing marine magic about them, you don't need an Indmar or even a GM. I would look for an Edlebrock or something like that to save money.

redlightning
08-25-2009, 09:41 PM
The temp is acutally stable till running at higher rpm for several minutes.
150-160 is stable. The temp creeps up very slowly.

I have purchased 5 tstats. from 2 different mastercraft dealers as well as Skidim.

the motor has never gone into limp mode.

I actually removed the heater connections for now until i get this resolved. Not sure if i will reinstall it. We just dont use it.

I think the temp sensor is in the drivers side head. I think i will replace it next and see what happens. I wish i had a MC mechanic i could have look at it that i trust.

Lev24
09-29-2009, 09:12 AM
I have a 1998 Prostar w/ the LT1 motor w/ about 450 hours. It is going into Norhtstar shut down mode after about 10 mins of operation. This problem just started out of nowhere about 2 weeks ago. I have...1) Cleaned the transmission cooler screen. 2) Checked the impeller which is new last year and working fine. 3) Changed the thermostat. 4) removed the water pump and flushed it and the ports into the heads with both water and compressed air. Boat runs fine out of water but the strange thing is that the water coming out the exhaust is cool. It is not steaming at all. It's like the water is not gettting through the heads. Any ideas?

Thanks!

Lev24

JimN
09-29-2009, 09:28 AM
I have a 1998 Prostar w/ the LT1 motor w/ about 450 hours. It is going into Norhtstar shut down mode after about 10 mins of operation. This problem just started out of nowhere about 2 weeks ago. I have...1) Cleaned the transmission cooler screen. 2) Checked the impeller which is new last year and working fine. 3) Changed the thermostat. 4) removed the water pump and flushed it and the ports into the heads with both water and compressed air. Boat runs fine out of water but the strange thing is that the water coming out the exhaust is cool. It is not steaming at all. It's like the water is not gettting through the heads. Any ideas?

Thanks!

Lev24

Check the ECT (Engine Coolant Temperature) sensor. It's the two-wire sensor with one yellow and one black wire. Use a multi-meter set to Ohms. If the resistance at ambient temperature is lower than what's in the chart I posted several times, it's bad. To test it further, remove the sensor, measure the resistance at ambient temperature and put it in hot water of a known temperature. Using the chart, compare the resistance at the higher temperature(s) with the chart. If it's not close, replace it.

If you're idling for a long time, occasionally put it in neutral and rev it up. If that doesn't help, clear out the bleeder lines from the heads to the intake manifold.

You also posted that you "changed the thermostat". Your motor has two of them. If you only changed the one in the normal thermostat housing, you missed the one behind the water circulating pump.

BTW- it's not a Northstar RPM reduction. This happens even with the motors that use a distributor.

Jerseydave
03-22-2012, 09:53 PM
Ok so I just purchased this '93 with an LT-1 and have not really run it much yet. (just a water test with the old owner)

I was going to install a new crossover tube on the front of the engine, but the alternator and bracket are blocking the right side cylinder head so it can't be done. I could remove the pipe plug on the left cyl head, but it seems pretty tight.

The previous owner didn't say he had any problems with it overheating, so I will try running it as is this spring and see what I've got.

Any other suggestions?

76669

gotta_ski
03-23-2012, 05:03 AM
That engine looks very clean. Did he tell you why the exhaust manifolds were either repainted or replaced?

I moved my crossover tube not because it was overheating but because my temp gauge was moving around alot and I thought it might be collecting air in the heads. Once I moved the tube I feel like it was more consistent, but that might be me just wanting to believe it made a big difference. Either way I sleep better. I would say run it and if it seems to behave like it should than don't stress it.

I like that high mounted alternator. Is that stock or an aftermarket setup? My 98 is low mounted, so the belt comes straight across from the crank.

Post more pics. Can you show us the details on were the two small braided hoses coming from the exhaust elbows lead?

Jerseydave
03-23-2012, 12:09 PM
'93 was the first year for the LT-1 so I think that high mounted alt bracket is stock.

The small braided hose on the top of pic goes to the steam tube at the back of the engine.
The small hose on the bottom of the pic goes to the top of the thermostat housing. I'm replacing all the braided hoses with plain black hoses. I think the p.o. repainted the exhaust manifolds with some special "coating".

76709

the only other engine pic I have right now

DooSPX
03-23-2012, 01:13 PM
'93 was the first year for the LT-1 so I think that high mounted alt bracket is stock.

The small braided hose on the top of pic goes to the steam tube at the back of the engine.
The small hose on the bottom of the pic goes to the top of the thermostat housing. I'm replacing all the braided hoses with plain black hoses. I think the p.o. repainted the exhaust manifolds with some special "coating".

76709

the only other engine pic I have right now

IMO Dave, those exhaust manifolds are aftermarket from Indmar, the orginial ones should be black and said MasterCraft Power on them...
http://i283.photobucket.com/albums/kk302/mistervelocity/003-36.jpg

Jerseydave
03-23-2012, 10:14 PM
You may be correct, so at least I know they are newer manifolds if that's the case.

What year is that engine in your pic? I ask because it does not have the steam tube on the front of the engine either.

Jorski
03-26-2012, 10:33 AM
Hey Dave,

As I mentioned before I also have a '93 with an LT-1...my alternator bracket does not look that.

It is low, and rotting...your set-up was likely a custom fix for a broken one. Either way, it is a much better set-up than mine came with.

DooSPX
03-26-2012, 10:50 AM
I believe it was a pic from a 95-97 boat... Yes, it could be a good thing they are new manifolds, you shouldnt have to worry about them for a while. Just paint them with black engine enamel paint. Or, you could upgrade to the MCX ETX manifolds, they look killer and should add a little boost in power. Dave at BAWS added them to his LT1 in the 93 Bud Pro-Tour boat. Also, if I remember correctly, Dave's alt. was high like yours in the pic Dave.

Jorski, post a pic?

Jorski
03-28-2012, 10:12 AM
I will post a pic when I can...boat is stored up near my cottage....2 hour away. Ice just went out the other day.

Once I get my hands on the boat, I will post a pic.

JerseyDaves set-up looks much better to me. I like the idea of having the alternator as high as possible, far removed from the bilge.

80starsmn
03-28-2012, 09:40 PM
Hi everyone, just something to add to this thread. I have a 96 PS 190 with the LT-1 and until yesterday it did not have the modification to move the steam pipe / bleed line from the rear of the heads to the front. I was not having any cooling issues during the short time I have owned this boat and didn't want to "fix something that wasn't broke" logic for not moving the bleeds to the front. First start up in the driveway after winter storage revealed a water leak from the port side steam tube. Further checking I found a rupture in the steam tube right near the attach point with the banjo bolt on the port rear head. What happend was scale, rust, crud all of the above migrated into the line and plugged the line trapping a little water, add freezing temps and you get a split line. Prior knowledge would have prompted me to add some compressed air through the bleed line from the manifold hose to clear out any obstructions last fall when I winterized. Needless to say my stock steam tube is junk (not enough length to clip off and attach a hose) and was a good excuse to make the modification as per the Service Bulletin from MC. I checked the local hardware store for the required brass elbows, tee, clamps and hose = just under $30.00. I then spoke with our local MC dealer to get their input on the Service Bulletin and to answer a few questions I had about the procedure. Our MC dealer, Midwest MasterCraft hear in Minneapolis, MN was an awesome source. They had done the procedure many times over the years and had the kit on hand that the service bulletin calls for at a whopping cost of 10 bucks! The Marks in the service department walked me through this simple procedure as per the service bulletin and offered any further assistance as needed. It took me 1 hour to make the mod and that was only because I had nothing else better to do. The plugs on the front of the heads back out with a 1/4" drive and replace the banjo bolts on the rear (after you have discarded the steam tube and bolts). Two brass fittings replace the plugs on the front of the heads with a short length of rubber hose running between the fittings on the heads. The starboard head is fitted with a brass T so as to connect the hose from the port head and the bleed hose running to the port exhaust manifold. Thats it! I like it so much better for another reason than cooling, it will be much easier to drain without clogging as the small ports in the old banjo bolts and tube are prone to do. Fired it up in the driveway, no runs, no drips, no errors. I can post some pics if anyone wants them. Special thanks to Midwest MC for being so helpful!!

pram
03-28-2012, 11:32 PM
I would like to see pics of this setup. I had the same thought as this in mind once I started looking at the tube and moving it to the front. I didn't understand why I wouldn't be able to use fittings.

Pics would be greatly appreciated

Jerseydave
03-29-2012, 03:49 AM
I would love to see pics of this as well. Plus do you have the part # for the kit? Thanks.

80starsmn
03-29-2012, 11:51 AM
Port side general

80starsmn
03-29-2012, 11:52 AM
Port side brass elbow

80starsmn
03-29-2012, 11:53 AM
Starbord side

80starsmn
03-29-2012, 11:59 AM
Front general, all parts used (except needed two small hose clamps for connector line) are contained in the kit #180200 as per the service bulletin MC96-001 for $10.00 in stock at Midwest MasterCraft Crystal, Mn (763) 533-9666. Local hardware store had parts on hand but 3 times the cost.

pram
03-29-2012, 05:35 PM
That is fantastic, talked to Corey and parts will be on there way tomorrow for mine to do the same

mattb
03-29-2012, 10:12 PM
I need to do this as well. Thanks for posting!

Table Rocker
04-10-2012, 02:02 PM
I finished rebuilding my water pump today. The bearings and seals are available on eBay. While I had the water pump out, I drilled and tapped a 3/8 npt port for my heater outlet. This will give me hotter water for the heater and still allow the water temp sensor to be inside the water pump. On gibbons fix, I didn't like that the sensor was moved back out of the flow of the water through the pump.
http://img194.imageshack.us/img194/251/img2398ej.jpg
I took this next pick to answer the FAQ: Which way does the upper thermostat go on my LT-1?
http://img840.imageshack.us/img840/4178/img2399a.jpg
And here it is buttoned up and ready to go back in the boat.
http://img190.imageshack.us/img190/8829/img2400xn.jpg

mattb
04-10-2012, 05:49 PM
Wow, that looks great. What made you decide to rebuild?

Table Rocker
04-10-2012, 06:38 PM
Wow, that looks great. What made you decide to rebuild? My bearings were shot, so it was rebuild or replace. An LT-1 water pump from inboardonline was $415, so I started looking to rebuild. I found the rebuild kit for $60 and ordered it. I later saw that the same guy was selling rebuilt pumps for not much more, but I'm glad I got the experience of doing it myself. I experimented a little with the paint job and cleaned up the impeller.

A rebuilt unit from Oreilly for a '96 Corvette is $140.00, so I guess I saved a little money over that option.

pram
04-10-2012, 09:21 PM
I got the kit installed last night

fired it up tonight no leaks so that is good

pram
04-10-2012, 09:21 PM
nice job on the rebuild

Table Rocker
04-10-2012, 09:50 PM
nice job on the rebuildThanks, hopefully it doesn't leak.

mattb
04-10-2012, 10:01 PM
Hey Pram what did you do with rubber cap that was included in the kit? I can't figure out why this was included? Also, did you use any type of sealant on all the fittings?

pram
04-10-2012, 10:06 PM
I didn't remove the bleeder tubes off the back of the heads, looked like it was going to be a solid pain in the butt so I used the rubber cap on the metal tube that came to the front with a hose clamp

pram
04-10-2012, 10:06 PM
http://www.mastercraft.com/teamtalk/attachment.php?attachmentid=77259&stc=1&d=1334107275


you can see it in this pic

mattb
04-10-2012, 10:13 PM
I didn't remove the bleeder tubes off the back of the heads, looked like it was going to be a solid pain in the butt so I used the rubber cap on the metal tube that came to the front with a hose clamp

Oh wow, not a bad idea. I wondered what that was in there for.

pram
04-10-2012, 10:18 PM
I hope that is what it was for lol

blackcreek
04-11-2012, 11:27 AM
My steam tube was completely clogged you could of left off that cap and no water would of come out anyway.

80starsmn
04-12-2012, 01:21 PM
Thanks, hopefully it doesn't leak.

Yep the rubber cap is to cap off the steam tube with hose clamp.

pram
04-15-2012, 11:44 PM
I have a question regarding the vent tube running in to the exhaust manifold.

Now I do not have a reference other than what I have now

The exhaust manifold side that the head vent tube runs into is substantially hotter than the other side

does anyone else find this?

temp was a solid 140 on the gauge today

blackcreek
04-16-2012, 07:51 PM
I have a question regarding the vent tube running in to the exhaust manifold.

Now I do not have a reference other than what I have now

The exhaust manifold side that the head vent tube runs into is substantially hotter than the other side

does anyone else find this?

temp was a solid 140 on the gauge todayIt is normal at idle for the riser to get hot at idle. http://mastercraft.com/teamtalk/showthread.php?t=33959&highlight=lt-1

My normal temp runs around 165 when underway. The 140 thermostat goes in the lower thermostat housing and the 160 goes on top of the water pump. The lower 140 thermostat allows the water to be warmed up before it is let into the motor and the 160 controls the running temp of the motor. You should be running 160-170 underway.

tappskier
04-22-2012, 09:44 AM
I have a 94 190 with the LT1, I had a problem a few weeks ago, the temp spiked and the small red light on the dash came on. The temp went right back down and we continued skiing. but the red light would not go off. I was concerned about this so after reading thru this post I changed both my thermostats, the impeller, swapped the crossover tube to the front of the heads and did the heater reroute. Went out skiing and every thing worked great, boat ran a constant 160 and the heater blew hot the entire time, the only problem being the red light came on again and will not go off,,, is there a reset for this? Can the sensor go bad? Thanks for any info and this great post on this subject.

JimN
04-22-2012, 09:57 AM
I have a 94 190 with the LT1, I had a problem a few weeks ago, the temp spiked and the small red light on the dash came on. The temp went right back down and we continued skiing. but the red light would not go off. I was concerned about this so after reading thru this post I changed both my thermostats, the impeller, swapped the crossover tube to the front of the heads and did the heater reroute. Went out skiing and every thing worked great, boat ran a constant 160 and the heater blew hot the entire time, the only problem being the red light came on again and will not go off,,, is there a reset for this? Can the sensor go bad? Thanks for any info and this great post on this subject.

Have you checked the transmission cooler for obstructions and to make sure the hose clamps are tight? What the gauhe shows matters very little if the ECM gets an overheat indication. Did it run badly when you saw the light? If not, you need to make sure the transmission has enough clean fluid- it could have been the transmission that has a problem.

tappskier
04-22-2012, 10:03 AM
I have two very small red lights on the dash, one is the transmission overheat and the other is the engine overheat. Its the engine one that is on,, the engine runs great, boat has 260 hours on it......

JimN
04-22-2012, 10:09 AM
I have two very small red lights on the dash, one is the transmission overheat and the other is the engine overheat. Its the engine one that is on,, the engine runs great, boat has 260 hours on it......

That's not just for engine overheat- it does the same as a car's check engine light. Check for codes. You can use any cheap code scanner or even a paper clip. The procedure has been posted here several times.

tappskier
04-22-2012, 10:19 AM
Ok, I didnt know that,, so theres a place to plug a code scanner? A paper clip? Where can I find this procedure? Thanks

JimN
04-22-2012, 01:51 PM
Ok, I didnt know that,, so theres a place to plug a code scanner? A paper clip? Where can I find this procedure? Thanks

I thought someone made it a "sticky" topic.

You have a great engine but you should read up on it to learn what it will, and will not, tolerate. Overheating is a huge issue because it has aluminum heads. Great for performance but they don't like to be overheated. The water circulating pump isn't the same as what's on a typical Chevy- it cools the heads before the rest of the motor.

Look at the rear of the engine for a gray plug on the end of a harness. It has a black plastic cover and the terminals are marked with letters. You'll need to bend a paper clip so the two ends are next to each other so you can insert them into terminals A and B. Once it has been inserted, turn the key to ON- you don't need to crank it. Watch the light flashes- it will flash once, pause and flash twice and this denotes 12. It does this three times before revealing any codes. When it's done with the codes, it will flash 12 again, three times. it will keep flashing the same sequence until you turn the key off, so don't worry if you miss it the first time through.

Report any codes you see. If it shows no codes, post that, too.

tappskier
04-22-2012, 02:26 PM
Ok,,, found the plug, inserted the paper clip into A and B........ what lights are supposed to flash? Where does it show the codes? I do have the new perfect pass system on the boat so the right side speedo is not there. Sorry for all the dumb questions. Thanks again

JimN
04-22-2012, 02:31 PM
Ok,,, found the plug, inserted the paper clip into A and B........ what lights are supposed to flash? Where does it show the codes? I do have the new perfect pass system on the boat so the right side speedo is not there. Sorry for all the dumb questions. Thanks again

Watch the check engine light. Don't care about speedo or any other gauges.

tappskier
04-22-2012, 03:41 PM
Ok did it again,,, no lights flash, nothing but a fast pace ticking noise from the front of the engine

Jerseydave
05-26-2012, 07:19 PM
Ok so I started my LT-1 today only to find my steam tube leaking at the back of the engine.
This would be a good time to use pipe plugs to block off the back of the heads and install fittings at the front of the heads with a connecting hose.
Only one problem, my alt is in the way on the right side (see pic in post 62)

Do I :

a) replace steam tube at back of engine with fittings and a hose like it was stock.
b) block off rear of heads with pipe plugs, install just one fitting on left head front.
c) somehow drill a large hole in my alt bracket to allow room for a fitting on that side as well.

Jorski
05-27-2012, 04:16 PM
Do I :

a) replace steam tube at back of engine with fittings and a hose like it was stock.
b) block off rear of heads with pipe plugs, install just one fitting on left head front.
c) somehow drill a large hole in my alt bracket to allow room for a fitting on that side as well.



A) You could do that...but it didn't work well in the first place. That's why there is a service bulletin.

B) You need to have a place for steam to escape from BOTH heads, not just one.

C) DING DING DING...

Some time ago I mentioned to you in this thread that my '93 LT1 alt. bracket looks nothing like yours, It sits much lower near the bottom of the engine.

You could get a stock bracket as an alternative.

Jerseydave
05-27-2012, 07:56 PM
A) You could do that...but it didn't work well in the first place. That's why there is a service bulletin.

B) You need to have a place for steam to escape from BOTH heads, not just one.

C) DING DING DING...

Some time ago I mentioned to you in this thread that my '93 LT1 alt. bracket looks nothing like yours, It sits much lower near the bottom of the engine.

You could get a stock bracket as an alternative.

After further examination I decided drilling a hole into the alt mount would be pretty tough, as there is some webbing in the exact spot that the hole would need to be. So I removed the original steam tube and replaced it with fittings/hoses. The tube was very clogged up with sediment anyway, doubt if it was working very well for the old owner.
Ran it on the hose in the driveway, all is well, no leaks. I'll keep an eye on the temp gauge and see how it works out. I know there are some LT-1's that have never changed the steam tube to the front of the engine, and this one has over 700 hours on it with the tube at the rear so we'll see.

Getting a low mounted alt bracket is a good suggestion for a long term fix. Thanks.

DRRICK
08-07-2012, 06:31 PM
Hello to Y'all. First read these posts in jan 2012, when I was starting to upgrade to roller rockers. I posted a thread about that rebuild.

When I went to remove the plugs from the front of the heads, the 1/4 " drive broke off. (Both sides)...........when I attempted to remove the banjo fittings, they came out with welded (not really but looked like it) aluminum in the threads.

I ended up re-tapping the rear holes, and installing barbs and running hosing up to a t fitting, such that the t fitting was higher than the holes in the front of the heads. This allows the steam to escape from both heads, but is not as elegant as the other solution.

I suspect that others will have the same problem if they wait too long to make the switch.

Boat runs rock steady temperature on the line between 120 and 180 on the temp guage. (160 +/-)

mgs96ps
05-19-2013, 04:12 PM
I didn't remove the bleeder tubes off the back of the heads, looked like it was going to be a solid pain in the butt so I used the rubber cap on the metal tube that came to the front with a hose clamp

Please correct me if I am wrong. If you order the kit, you can simply add new parts to front of heads and leave everything on the back as is, provided you cap it off?

Legolamb
05-20-2013, 08:02 AM
Correct. I left my tube on the rear and used rubber cap and clamp on tube running to front.

jakethebt
08-28-2013, 06:46 AM
http://www.mastercraft.com/teamtalk/attachment.php?attachmentid=77259&stc=1&d=1334107275


you can see it in this pic

That is the way they did mine too. I have had no issues. I considered changing it to plugs. So leave well enough alone or put the plugs in it?

Kevin@MWMC
08-28-2013, 07:25 AM
Please correct me if I am wrong. If you order the kit, you can simply add new parts to front of heads and leave everything on the back as is, provided you cap it off?

Just an FYI for everyone, the kit that MasterCraft was using for the Service Bulletin is no longer available. I've had 4-5 people call this year for this kit and it is no longer made. You could try to call some dealers and maybe get lucky and find a dealer that might have an extra kit laying around. We sold our last one over a year ago.....


Sent from my iPhone 4S using Tapatalk

jakethebt
08-28-2013, 05:42 PM
Thanks Kevin. Ay chance we can get some info on what was one kit? Parts list, install info, pics or maybe service bulletin. May help to complete the thread.

Kevin@MWMC
08-29-2013, 05:34 PM
Please see attached PDF file.

johnboat
09-04-2013, 09:38 PM
Thank you! Made the changes and it ran all last weekend at 160F. Happy Winterizing all!

bochnak
10-07-2013, 04:49 PM
Hey Gibbons,

You the same guy from chevelles.com? I'd send you a PM but don't know if your account is active?

gibbons
01-08-2014, 10:59 PM
Bochnak, yep, that's me too. I just saw your 3 month old PM, haven't messed with the Chevelle for a long time.

I just logged in to see what trouble I caused here! It doesn't look like anyone changed to a 170 thermostat, that's where the fun starts because the heater is hotter and it still won't heat spike. I got an engineer in the product development lab at Stant to custom make me a couple way back when. But I later found 170 stats off-the-shelf at Summit Racing. Get one of these! Remember to drill a 1/8" bleed hole on the skirt. http://www.summitracing.com/parts/mez-wn0070170/overview/

Our kids are all gone and the ProStar hasn't been on the water for 2 years. I rode my bicycles 11,000 miles instead. It's strange how interests change.

bochnak
01-09-2014, 06:12 AM
Bochnak, yep, that's me too. I just saw your 3 month old PM, haven't messed with the Chevelle for a long time.


Ha! I haven't messed with mine that much either. Going to do a a H4/H1 headlight swap & relays this winter.

mgs96ps
02-08-2014, 02:32 PM
Finally doing the LT1 cooling fix. It seems to me that my boat maintains the 160 temp but I have decided put vents at the front of heads for good measure. I will be leaving the stock vent tube at the rear and capping off the tube running toward bow. Has anyone, instead of capping off existing tube, just plumbed it into new hardware on front? That way steam could travel the least path of resistance and escape either toward the front or rear. Overkill?
Attached are some pictures of hardware.

Table Rocker
02-08-2014, 02:41 PM
Has anyone, instead of capping off existing tube, just plumbed it into new hardware on front? That way steam could travel the least path of resistance and escape either toward the front or rear. Overkill?
That is what I did. I bought a used factory steam tube and put it on the front. I plumbed the rear tube into the hose to the manifold with a brass tee. I figured if it ran too cool, I could block it off later. I did drill another hole in the thermostat to make sure enough water could flow in just to be safe. All said and done, it works great.

mgs96ps
02-11-2014, 01:12 PM
That is what I did. I bought a used factory steam tube and put it on the front. I plumbed the rear tube into the hose to the manifold with a brass tee. I figured if it ran too cool, I could block it off later. I did drill another hole in the thermostat to make sure enough water could flow in just to be safe. All said and done, it works great.

TRocker,

Do you see any issues with attached image of how I am thinking of updating my steam vents?

Table Rocker
02-11-2014, 02:28 PM
TRocker,

Do you see any issues with attached image of how I am thinking of updating my steam vents?
I can't think of any reason it wouldn't work fine. The hose from the bubble catcher is small, so you would probably replace it with the larger hose and larger brass fitting on the manifold.

epnault
02-11-2014, 02:51 PM
Hi Guys,
I just bought a boat with an LT1 a couple of weeks ago. Does it look like mine has the bulletin completed. I wish I had better pics but it is in storage 10 hours away where I bought it.
Thanks,
Eric

Table Rocker
02-11-2014, 03:04 PM
It does not look like it has been changed.

It does look nice and clean though, very nice.

epnault
02-11-2014, 03:11 PM
Hmm. It looks like the 2 lines are routed (from each manifold) to the front of the engine. Am I seeing something wrong?

Table Rocker
02-11-2014, 03:22 PM
Hmm. It looks like the 2 lines are routed (from each manifold) to the front of the engine. Am I seeing something wrong?The rear steam vent has a long tube that runs up to the front of the engine. The hose attaches there (near the front) and goes to the right side manifold. The other hose comes off the water pump thermostat housing and runs under the K&N to the left manifold.

You can see on Pram's pic earlier in the thread where he has the tube from the rear capped off with a black cap and a hose clamp.
http://www.mastercraft.com/teamtalk/attachment.php?attachmentid=77259&stc=1&d=1334107275

mgs96ps
02-11-2014, 04:15 PM
Hi Guys,
I just bought a boat with an LT1 a couple of weeks ago. Does it look like mine has the bulletin completed. I wish I had better pics but it is in storage 10 hours away where I bought it.
Thanks,
Eric

epnault...if that new boat of yours does not have a heater or shower, most likely you would be fine leaving things as they are. Of course I am not doing that and will be adding the vents to the front of my heads because it seems like the consensus, its cheap and does not hinder anything. If you read through this thread, it looks like most have closed off the back existing vents, (except TRocker to my knowledge). I think leaving an escape front and back is a good idea...and you can leave existing setup alone. IMO More important than changing steam vent around is to change out the (2) tstats often....I treat them like the impeller. This may be overkill, but I only have one MasterCraft in my fleet. I recommend getting up to speed on the (2) tstats and how they work in the LT1 and understand the flow of water thru the powerplant.

epnault
02-11-2014, 04:50 PM
Thanks - do you recall where I can read more about the LT1 in MC?

mgs96ps
02-11-2014, 04:53 PM
epnault,

I could be wrong...but I think you have steam vents on the front of your heads. When I look at the picture of your engine I see an extra hose just behind air filter on the starport side that I can't identify...it also seems like there is a banjo bolt in the pocket near the ignition bank.

Would need picture of other side of engine to confirm. Others can pipe in.

blackcreek
02-12-2014, 05:30 PM
Thanks - do you recall where I can read more about the LT1 in MC?

1. click the search menu up top
2. click on advanced search
3. type lt-1 into keywords
4. select title only and hit search.

you need to have more than 3 letters in the keyword area for search so use a dash and type lt-1

mgs96ps
03-15-2014, 11:40 PM
Check me in for completing the steam vent update. Made the switch a roo with a host of other things today.