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TCrate
10-08-2006, 11:29 PM
Bad news today. Winterized the boat (1992 Prostar, 285) and when I was pulling plugs to fog the cylinders. Discovered a water trace in three places between the head bolts/manifold bolts. At first I thought it was coming out of the manifold bolts but clearly there are three hairline cracks in the head.
A new GT-40 head is around $695 plus labor to install.

Anyone have any suggestions on where I can find heads cheaper?
Is this a common issue with these heads?
Anyone had any luck with welding these types of cracks?

I do not think it is from freezing. I think it is thermal shock as I have had problems with the overheat signal coming on after I start again after changing out skiers. Once I get the engine running it cools down to normal around 170 degrees. The temp is fine when running.

edwinfuqua
10-09-2006, 02:02 AM
Bad news today. Winterized the boat (1992 Prostar, 285) and when I was pulling plugs to fog the cylinders. Discovered a water trace in three places between the head bolts/manifold bolts. At first I thought it was coming out of the manifold bolts but clearly there are three hairline cracks in the head.
A new GT-40 head is around $695 plus labor to install.

Anyone have any suggestions on where I can find heads cheaper?
Is this a common issue with these heads?
Anyone had any luck with welding these types of cracks?

I do not think it is from freezing. I think it is thermal shock as I have had problems with the overheat signal coming on after I start again after changing out skiers. Once I get the engine running it cools down to normal around 170 degrees. The temp is fine when running.

You might find someone that can TIG those heads. But it sounds like you should keep your motor running after a pull so things can cool down a bit before shutting her off. I don't know how you guys deal with all that aluminum stuff and cold water intake. Sounds like trouble no matter what you do.

Edwin

edwinfuqua
10-09-2006, 02:05 AM
Make sure if you weld the cracks that you don't just let anybody do it. Another thing is make sure you drill a hole at the end of each crack to stop it from running furthur.

Heck anything can be fixed, weigh the alternative if the fix don't work. Is it worth the time and effort? Drop a 454 HO in there like mine... heee. hee.

Edwin

dchatagnon
10-09-2006, 03:48 AM
I have also discovered that I got a GT40's head cracked this summer.
Same issue as you.
I bought 2 complete new ones from DIM and the engine works perfectly now. Of course it cost some $$$$.

I still got one of my old two heads in perfect condition.

tdaines@hotmail.com
10-09-2006, 06:26 AM
I think you might be able to track down used ones, or maybe some that are just rebuildable. Drop another post titled, "USED GT40 Heads?" and see if someone responds. It might be worth asking dchatagnon if his remaining survivor is the one you need...

One thing I would do for sure if you get used ones - have them magnafluxed to check for cracks and spend the few hundred dollars for a rebuild - new 3 angle valve seats, and all new running gear.

Good luck - I'll keep my eyes open around here for some used GT40s.

TIM

Leroy
10-09-2006, 07:40 AM
Have you searched ebay?

http://search.ebay.com/search/search.dll?cgiurl=http%3A%2F%2Fcgi.ebay.com%2Fws%2 F&fkr=1&from=R8&satitle=gt40+heads&category0=

east tx skier
10-09-2006, 12:22 PM
See if you can get a pair of GT40p heads of a late 90s explorer with a V8.

rcnjson
10-09-2006, 05:30 PM
Are they cast iron or aluminum? GT-40 heads come in many different variations. The ones on the explorers are cast iron. There are also some aluminum variants of the heads. An aluminum head can be repaired by welding, I guess you could repair a cast iron head by welding but I don't think anyone does. I think it just creates an area that is even more brittle than what you started with so it may be repaired, but not for long.

dchatagnon mentioned that he has one perfectly good head laying around. The nice thing about small block fords is the heads are the same. That is correct, the head on the right side of the motor is the same as the head on the left side. The drilled and tapped holes are all there for accesories, just one gets flipped for the other side. The only thing you may have to change is the plug for the egr. It might be in one of the accesory holes and you have to move it to the opposite side of the head, no biggy.

I don't think this is a thermal shock issue. It might be, but if the cracks are around the bolt, it seems to me that the bolt could be causing the stress. I am assuming it is one of the bolts that is visible with the valve covers on. So that is just the bolting flange of the head, there are only small water passages in that area. If it was one of the bolts under the valve cover at the very front or very back of the head I could see that because that is where the large water passages from the intake manifold come into the heads. If it were thermal shock, the high probability region would be the left side of the motor looking at it. That is where the water comes into the intake manifold and on into the head. Basically that would be the coolest water your head sees. The reason I said the bolt causing the stress, is if for some reason the head gasket was replaced and the bolt was over torqued, or not lubricated, it could be causing stress in that area. Is it possible that the head gasket has been replaced?


I run aluminum heads on my motor, no problems with expansion / cracking/ sealing/ overheating.

k

johny_Utah
10-10-2006, 12:21 AM
I just replaced the heads in my 89 190. I got them from First Mate Marine AKA Marshal Engines. They where 220 apiece. Here is the link

http://www.firstmatemarine.net/

J.

TCrate
10-19-2006, 11:07 PM
Are the new motors coming out with aluminum heads now or are they still cast. Why would they not go to aluminum.