WILDTHING TAZ

i would leak down test,it will tell you where the air is going.leak it down with all rockers loose.i think you leaned out and cooked the valves.if anyone is going to quit it's going to be me!!!just reach in your wallet like we all do. boats are still cheaper than women. RB

Tinkerer

I have been told that spark knock can loosen the plugs also.

wetterthebetter

My oppionwould be yes on pullen the head,simply be bause you burned the tips on the plugs,and that was not the only thing that got hot like the valves.Head and intake gaskets are cheaper than dropn a valve because you didnt go the xtra mile to make sure its right..................


Later Stan
Just a thought, Not a sermon

THRILLSEEKER

Thanks a lot for all the info guys I pulled the heads and the valves are definately fried

Now, I dont have the time to mess with theese things, so I am just going to drop them of at a shop that does heads, is there anything that I need to inform them about as far as ordering parts....valves and springs????? do they need to be a special hardened material or anything for marine use also will the valve seats needd to be reground or should they be ok?

Next question, do you think that a loose plugs is the cause of this whole thing, or do I need to look for something else?

28SS

for valve have them use the manley severe duty valves on exhaust/ inconel . springs sould be fine/ just check pressure
seats will be ground to valves / yes loose plug can do this damage as stated before. you redid both motors correct ?
other moter sounds like it runs correct. so I think you just slipped up on torque of plugs. You wont do that again will you now

blue thunder

If you are looking for opinions, I have one. Your plugs are loose due to detonation (as tinkerboat said). This could be caused by many issues, but I would look at the exhaust. Water in the cylinders from leaking exhaust is my guess. Check it now, or when you blow the next one, but check it. Look for rust trails.

BT

paradigm shift

I am no expert and you have been given some good advice. I agree loose plugs will burn up but fried or tulip-ed valves usually mean LEAN in my experience. ( Been there done that) Detonation can be caused by many things. I would double check cam timing while it is down. Verify ignition timing and advance curve is correct. If you are not running a fuel pressure gauge I would install one now at least for testing and set up. Double check that carb and run some plugs checks when you get it running right away. I would make sure it is running plenty rich to start with. You can always lean them down. Sorry for all your trouble I hope you get it sorted out before you melt down. Inconel valves on exhaust and stainless on intake sis the way to go. Personally I like to run a fairly wide seat to help the valves cool. Not so bad on a normally aspirated motor but on a blown motor for sure. I will gladly give up a couple HP to make the valves live. Just my .02 and good luck.

No I don't think loose spark plugs are your only problem.

Oh yea DON'T QUIT! I will save the wise cracks you are probably not in the mood.

HyperBaja

Tony, get rid of the small blocks, I bet we could get some 454mags in there nicely...