JSV

Lee

Not to start an arguement but if what you are saying is true, then why dont all mechanical rollers fail for that same reason?

blue thunder

I have a matching grenaded 454magnum on my garage floor. Cept it was #1 that dropped the exhaust valve head. The way I figure it went was:

* heat caused distortion of exhaust valve

* exhaust valve stopped seating well

* exhaust valve start sucking water from exhaust on intake stroke

* combustion chamber shrunk volumetrically due to water taking space and compression sky rocketed

* detonation/heat

* valve head left stem

* oh ****

BT

huge

I appreciate the input guys, the comp ratio is 9:1. I have been running the comp270H since 1996 when I put it into the stock 7.4liter. The cam works fine and is still in great shape. the valve seats are all intact and i magnafluxed the head and no cracks were found. I have stainless marine exhaust and have pulled the risers many times on the water to check for reversion. I'm sticking to my theory that this was an isloated case of a bad valve or metallury problems! I've got my local autoparts shop on side going after merlin for some warranty. I'll keep you posted. I've located a block already. A Gen V bored 30, decked and cam bearings installed for $750 cdn. or about $470 usd.

jpclear

They tried to tell me it was a flawed valve, too. I trusted them and that's why I had to do it all over again. If you don't go inconel or equivilent, you too will probably become a reluctant expert. --- Jer

huge

I have every intention of using inconel exhaust valves. I just ordered them today. They ain't cheap, are they!

jpclear

No they ain't. Huge; But they be MUCH cheaper than the second rebuild. And anyhow, It's Summertime and we don't want to be in the machine shop watching the boreing machine do it's thing, now do we??? Get back to the waves soon!!! --- Jer