Quote:
Originally Posted by GLH
Might have too much exhaust flow because of the headers and taking out exhaust components and/or an exhaust leak up high and/or poor mating at the header-head mounting.
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I like your thinking, same issue many have on our bike motors if the front pipe is not sealed to the head it pops on shift and deceleration and will burn a valve if not taken care of.
I thought that MIGHT be possible except for the fact that the pics above were from the stock motor with stock manifolds and cats. No leaks.
No leaks now between the headers and heads now either.
I scoured that thing looking. when we pulled the headers to pull the heads this time all the mating surfaces on the gaskets showed positive sealing all the way around.
What is REALLY intriguing is when you look at the Picture #1 closely you can see that the valve seat IS MISSING! when we pulled the heads we were stumped and like... WTF??? we have seen them bad, seen them recessed, seen the cracked and even see the valve beat up so bad it is actually down inside the seat. Seen valves burnt, chipped, bent and even have a small line of burn out. But to have MULTIPLE cylinders where the exhaust Valve seat is TRULY MISSING... WTF??
Even more puzzling... NO EVIDENCE of the seat falling into pieces and scarring the piston, head, valves or cylinder bore? When a spark plug electrode or even foreign object gets into a cylinder it leaves dings, dents, scratches or other evidence of it bouncing around and causing havoc. NOTHING! You can even see evidence of just that in the cylinder where piston came apart!
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Carl Corey,
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1976 Ford Elite "Lola Mae", Gran Torinos- 72 Formalroof "Ol'Brown"4 additional parts cars (2x72, 1x73 Formalroofs) and a 72 GTS
90 T-Bird SC, 3.8l SUPERCHARGED, 97 Suzuki Intruder 1400
01 Ranger Ext cab, 2wd, 3.0(flexfuel?)/Auto
US Army Retired('12)