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View Full Version : '92 190 Prostar 351W Indmar / cracked head


lazyade
09-04-2011, 03:36 PM
Hi,

Myself and a few friends have recently purchased the above boat. The boat itself is in really good condition, but the engine needs some work. We've found a crack in the water jacket on the left cylinder bank (cylinders 5 to 8). We did take the head off any have it welded but unfortunately after putting the head back on yesterday it is still leaking. I have done some searching on the forum put would appreciate some guidance and comments...

1) Firstly I think I'm right in thinking we have the 351 HO engine, 5.8 ltr with 285 hp. Would I have the GT40 head fitted as standard on the 1992 boat? Is there anyway I can check? Am I able to fit any other heads (eg 302 ones)?

2) Even if I don't currently have the GT40 head I believe this is the best head to replace mine with? I believe I just need to replace the plugs with a brass one, due to salt water use.

3) Anyone know of a dealer in the UK who might have heads for sale (shipping is likely to be loads from the US to UK)!

Thanks in advance.

A.

j.mccreight@hotmail.com
09-04-2011, 04:25 PM
Yes if you should have the gt-40 heads as standard they have 3 bars on the end of head for idenification, If you can't source one you can go with the p-heads they have 4 bars out of an explorer and drill out head bolts and install brass freeze plugs to fit on the 351, if you cant source that head you can go to the std low hp e5-te head which has 2 bars or no bars but you'll reduce hp by about 30 hp.

mark g
09-04-2011, 05:20 PM
Do a search for Rodley motors in Leeds they stock all us car parts,
Secondly do a search for wake and ski, Simon should be able to sort you out.

lazyade
09-05-2011, 09:14 AM
Thanks for the replies. My friend checked our current cylinder head today and we couldn't see the three bar markings in the head. It did have what looks like MM and the number 13 stamped on it (and IJI2 19753 and MM and 3 on the inside of the Rocker cover). If we have the GT40 head would it have the three bars stamped in it, or do Indmar remove these bars?

A.

lazyade
09-05-2011, 09:29 AM
Sorry one other question, if we dont currently have the GT40 heads can we simply add them (noted we may need to change the bolt holes and brass freeze plugs)? I did hear that we would need to change the intake manifold, would this be the case?

Thanks.

j.mccreight@hotmail.com
09-05-2011, 11:01 AM
Only have to change intake manifold if your going from a 302 to a 351 or vise versa the width of engine is different, heads are same physical size, 351 std and 351 ho were both available in 92, so if you dont see the marks then you have the std 240 hp engine. Indmar does not remove marks. If you remove the head and look underneath "gt-40" will been stamped on the surface where the head meets the block.

Another way to tell which engine you have is by the carburetor, 4160 is std, whereas 4010 is the ho, this is not fool proof, as people with the 4010 regularly swap out carburetor for the more reliable 4160.

Dino Don
09-05-2011, 01:11 PM
Sorry one other question, if we dont currently have the GT40 heads can we simply add them (noted we may need to change the bolt holes and brass freeze plugs)? I did hear that we would need to change the intake manifold, would this be the case?

Thanks.

I have a set of those heads I just pulled from my 190. I replaced them with later model heads. My used ones are fine no issues at all no cracks or valve leakage-can be put right on. PM me if interested in one or both.

lazyade
09-05-2011, 02:01 PM
Cheers for the offer Dini Don, I'll discuss with my boat colleagues.

One question on a GT40 head upgrade, I'm being told that if we upgrade to a GT40 head (from the current head) then it will affect the compression ratio and will affect our hole shot. Personally I cant see how changing a head will have any real impact on compression ratio, but I'm no engineer! What do you guys/girls think?

thatsmrmastercraft
09-05-2011, 02:19 PM
Not sure specifically if the GT-40 has a smaller chamber area than the standard head, but if the chamber area is smaller, it will raise the compression ratio. An old trick from the 1950's - 1970's to getting more power from engines is to mill some off the face of the head which will also raise the compression ratio. One has to be careful doing this to be sure there isn't any valve interference issues.

lazyade
09-05-2011, 06:25 PM
If the head does change the compression would I need to do anything with the timing?

Dino Don
09-05-2011, 08:00 PM
If the head does change the compression would I need to do anything with the timing?

I'm running GT40P heads @ 10 degrees BTDC ran the ones I took off at 10 degrees. Smaller chambers and more compression and more HP. I am also running flat top pistons which increases the compression ratio but GT 40 heads will up the power some if you just change the heads. "P" heads will require some machine work to use them they use 7/16 bolts and a 351 uses 1/2 inch bolts--no big deal to drill out but get them done correctly if you go that direction.

lazyade
09-06-2011, 06:57 PM
It looks like we're going to try and get a straight swap for our lower hp heads. Some folks here in the UK have advised that if we go for the GT40 heads then the higher compression will mean we'll have to run at a higher rpm when towing a skier. Also we've been advised we would have to get involved in changing the timing. Given there's 5 of us in the boat share I fear the others will think it's too much of a risk (but I know what I'd be doing if it was my boat)! Thanks for all your posts.

thatsmrmastercraft
09-06-2011, 07:02 PM
Not that I would try to talk you out of your decision, but you would not need to change the timing, and you slalom RPM would actually be a little less with more horsepower on tap. The GT-40 heads would not offer you any gains in you slalom skiing. Sounds like staying with what you have is the simple answer.

Jorski
09-06-2011, 07:10 PM
Not that I would try to talk you out of your decision, but you would not need to change the timing, and you slalom RPM would actually be a little less with more horsepower on tap. The GT-40 heads would not offer you any gains in you slalom skiing. Sounds like staying with what you have is the simple answer.

If using the same prop...you will go exactly the same RPM to go 36mph (or 34) as before.

However, with more HP you may be able to swing a higher pitched prop, and therefore reduce rpm for a given speed.

gr82bgreen
09-07-2011, 12:21 AM
It looks like we're going to try and get a straight swap for our lower hp heads. Some folks here in the UK have advised that if we go for the GT40 heads then the higher compression will mean we'll have to run at a higher rpm when towing a skier. Also we've been advised we would have to get involved in changing the timing. Given there's 5 of us in the boat share I fear the others will think it's too much of a risk (but I know what I'd be doing if it was my boat)! Thanks for all your posts.

There is no difference in RPM with different heads. The trans and prop control RPM. There is no downside to more HP. Timing remains the same. There is only better acceleration and performance. Search this forum. Many members have done it. Its a simple effective swap.

lazyade
09-09-2011, 02:11 PM
I've now taken the current head off and have found the casting numbers, they are: E8JL AA

https://lh6.googleusercontent.com/-BrcJ-xl1X-Q/TmpIj5G8geI/AAAAAAAAAVo/PmjlFH2ddD4/s400/photo%25255B3%25255D.JPG

j.mccreight@hotmail.com
09-09-2011, 04:17 PM
Those heads are 1988 industrial engine heads.

lazyade
09-09-2011, 04:28 PM
Those heads are 1988 industrial engine heads.

Thanks James (wow you've been a real help so far). So if these are industrial heads, are they "standard" for the Indmar, or has one of the previous owners exchanged the heads? (if so any idea what the 'std' heads casting number is?) As an FYI haven't had any luck finding GT40 heads in England yet.

Cheers... Adrian

Dino Don
09-09-2011, 04:47 PM
Thanks James (wow you've been a real help so far). So if these are industrial heads, are they "standard" for the Indmar, or has one of the previous owners exchanged the heads? (if so any idea what the 'std' heads casting number is?) As an FYI haven't had any luck finding GT40 heads in England yet.

Cheers... Adrian

Adrian my heads off my original 87 pro Star 351 Indmar have a casting number of E5AE CA. I believe that the Indmar engines were all basically industrial type engines or least the earlier ones were. Cast decoder says E8JL were 302 heads but were listed as industrial. Mine are listed as truck style heads but 351 by the decoder. Can't find any info on cc's on head volumn or valve size.

j.mccreight@hotmail.com
09-09-2011, 04:58 PM
dont know if this company is close to you but they say they have those heads, from my research ford used those heads originally on engines for industrial OMC engines, indmar prolly just bought overstock. my heads are e5-te meaning 1985 casting for a truck if the "t" is an "a" than it was originally intended for a car.

http://www.trickettmarineproducts.co.uk/engines.html

i am thinking 2,100.52 + vat is prolly more than your willing to spend

lazyade
09-09-2011, 05:05 PM
dont know if this company is close to you but they say they have those heads, from my research ford used those heads originally on engines for industrial OMC engines, indmar prolly just bought overstock.

http://www.trickettmarineproducts.co.uk/engines.html

i am thinking 2,100.52 + vat is prolly more than your willing to spend

I've actually written to them, enquiring just about the heads, am awaiting a response.

Just out of interest there are a few cheaper E7-TE heads on eBay. Are these any good for the Indmar, would they just bolt on, what are they like for HP (compared to the E8-JL or GT40)?

j.mccreight@hotmail.com
09-09-2011, 05:15 PM
I've actually written to them, enquiring just about the heads, am awaiting a response.

Just out of interest there are a few cheaper E7-TE heads on eBay. Are these any good for the Indmar, would they just bolt on, what are they like for HP (compared to the E8-JL or GT40)?

e7te heads are 1987 truck heads and would be similiar in hp to what you have now, you would not have to change anything just the freeze plugs, just bolt them on and go.

j.mccreight@hotmail.com
09-09-2011, 06:04 PM
here is a chart that breaks down all the sbf heads with some aftermarket ones as well, however the e8jl are not listed

http://www.carbdford.com/tech/flowdata.htm

e5 are low man on the totem pole next best is e7 then the gt-40, then gt-40p

i wonder if those ebay ads that say free shipping apply to you brits:D
just remember if you get a set off a 302 you will need to drill the head bolt holes out to 1/2" or I guess 13mm for you metric people:rolleyes: