huge

Well. It happened. I built a mild 454 last summer with these specs. 1994 GenV block turned cast crank 10-10, KB 203 pistons, merlin oval port 269cc heads 2.19 1.88valves, comp cam270H, stainless marine exhaust, eldebrock performer 2-0, AFB 750 carb. The head of the exhaust valve on # 5 broke away from the stem and pretty much disintergrated the engine! I feel that this was extremely pre-mature metal fatigue in the valve. what do you think?

huge

The engine only had 50 hrs on it

huge

One last pic to show, oh yeah it split the block too!

jpclear

Oh how I hate those pics!! Seen this TWICE on mine. Of course I was too f@!#*%# dumb and cheap to scrap all the ex valves the first time cause I was assurred that it was just the freak single defective valve. For ANY sort of HP marine application you MUST use Manley EXTREME duty ex valves or the equivilent. Anything less (such as their severe duty pieces) will just NOT cut it in a marine application. Just another reason to be sure that your engine builder is a MARINE engine builder, not the local street rod shop, no matter how good he is. I feel your pain! --- Jer

mxz800

That just plain SUCKS i hope you have a speedy recovery!

tomcat

Looks so familiar!! The best exhaust valves are a must but also check to make sure you don't have reversion or a leak in the exhaust manifolds allowing cold water to hit hot exhaust valves. First time this happened to me I thought it was just abuse (poker run) but the second time it happened I checked and found that the SS riser on my Gil exhaust was leaking. You run it hard, get the exhaust valves red hot, then you idle for a while sucking cold water into the exhaust port. The metal can only stand so many cycles of this before it becomes brittle... then boom!

Only good thing about it, this is an excuse to build more power into the next engine. Good luck.

huge

I have checked for reversion in the past and everything is OK. I am definitly gonna put some high end valves in this time. Here is what I need; Gen V 454 block, suggestions for a good and cheap(is this possible?) inconel exhaust valves, what type of intake valves? I'm just puttin this thing back together for as little as possible. I'll have to order one Kieth Black piston from the factory(KB 203 +.030) and have it and a new rod balanced to the rest of the piston/rod assemblies. The other pistons are in great shape(why not with 50 hrs!) I'll throw new main and rod bearings in it and back to the water in 2 weeks if everything goes well!!

Audiofn

Dude that totally sucks L( I feel your pain

Mbam

Can you post an extreme close up of one of the valve tips (where the rocker arm rides). I want to see if you were floating the valves.

FloridianSon

Copy Cat Did mine three months ago!