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  #41  
Old 08-11-2009, 10:11 PM
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JimN JimN is offline
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Originally Posted by gibbons View Post
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?
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  #42  
Old 08-11-2009, 10:18 PM
gibbons
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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!
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  #43  
Old 08-11-2009, 10:23 PM
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JimN JimN is offline
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Originally Posted by gibbons View Post
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?
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  #44  
Old 08-11-2009, 11:23 PM
gibbons
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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?
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  #45  
Old 08-11-2009, 11:59 PM
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JimN JimN is offline
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Originally Posted by gibbons View Post
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.
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  #46  
Old 08-12-2009, 02:38 AM
redlightning redlightning is offline
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Boat: 1994 Mastercraft 225VRS LT1
Location: South Central
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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?
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  #47  
Old 08-12-2009, 10:55 AM
gibbons
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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?
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  #48  
Old 08-12-2009, 04:12 PM
redlightning redlightning is offline
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Boat: 1994 Mastercraft 225VRS LT1
Location: South Central
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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.
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  #49  
Old 08-12-2009, 08:02 PM
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JLeuck64 JLeuck64 is offline
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Boat: 98 Prostar 190 Stars & Stripes, LT1
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Quote:
Originally Posted by gibbons View Post
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.
Attached Images
File Type: pdf lt1 cooling.pdf (17.0 KB, 386 views)
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http://www.mastercraft.com/photopost...er=2572&sort=1
Need LT-1 parts?
OIL FILTER: Factory installed is a Penzoil P23, Afta market brands, AC Delco PF-454 and a Fram PH-13 or PH-30 will work.
SPARK PLUGS: AC Delco MR43LTS (gapped to .040")
FUEL FILTERS: AC Delco 25171391 (pump inlet side)
89058397 (pump outlet side)
IGNITION WIRES: Call Inboard Online @ (877) 327-7175 and order part numbers 556010A (odd bank) and 556010B (even bank)
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  #50  
Old 08-12-2009, 08:12 PM
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JLeuck64 JLeuck64 is offline
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Boat: 98 Prostar 190 Stars & Stripes, LT1
Location: Oregon
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Quote:
Originally Posted by captain planet View Post
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. 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!
__________________
http://www.mastercraft.com/photopost...er=2572&sort=1
Need LT-1 parts?
OIL FILTER: Factory installed is a Penzoil P23, Afta market brands, AC Delco PF-454 and a Fram PH-13 or PH-30 will work.
SPARK PLUGS: AC Delco MR43LTS (gapped to .040")
FUEL FILTERS: AC Delco 25171391 (pump inlet side)
89058397 (pump outlet side)
IGNITION WIRES: Call Inboard Online @ (877) 327-7175 and order part numbers 556010A (odd bank) and 556010B (even bank)
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