Could anyone think of a scenario where the heat soak caused from the defective heads or metal from the valve guide wear could cause piston damage? I would think excessive heat could cause detonation which in turn could break up a piston...? I have reasons for asking this, but I can't explain right now.....
Could bad heads cause Piston Damage???
- Thread starter Tiffer J
- Start date
Of course it can.
An over heated engine can lead to a number of things, including marring of the cylinders/pistons, not just detonation damage.
An over heated engine can lead to a number of things, including marring of the cylinders/pistons, not just detonation damage.
detonation can, but not usually on a forged pistons. Forged pistons dont generally break up, they get mangled and stay in one piece. I would think if a forged piston broke up into many small pieces, it would be a manufacturing defect.
Hyperutectic or however it is spelled pistons can break up from essentially any abuse.
Hyperutectic or however it is spelled pistons can break up from essentially any abuse.
On another note, heat doesn't generally cause a forged piston to break up, but something like a spark plug or valve falling into the cylinder could do it.
The Mod Motor is designed so that the valves will hit the pistons if the valve timing is off (interference design). I'm not sure I believe it, but one tech says that valves can hit the piston if the cam timing is off by only 1 sprocket notch. Guess something could happen in the head that would cause this to happen, even as simple as the chain between the intake and exhaust cams breaking.
What generally causes piston failure is over temperature in the combustion chamber. Fooling with the a/f ratio, advancing timing, or running 87 octane gas and stressing the engine. It starts with a hole in the top of the piston, and then the piston shatters.
Has somebody done something they wish they hadn't?
Has somebody done something they wish they hadn't?
I've never seen a Hyperutectic piston of a regular 4.6L, but I have seen them on an Integra. The pistons actually had notches in them to clear the valves. I could see how damage could occur if the timing were off.
However, I've seen the Cobra's DOHC forged piston and they are dished to accomidate the increased cylinder pressures from the blower. I'd imagine this would give some extra clearance.
What do you guys think?
However, I've seen the Cobra's DOHC forged piston and they are dished to accomidate the increased cylinder pressures from the blower. I'd imagine this would give some extra clearance.
What do you guys think?
The engine is an interference design, the dish was probably to lower compression.
I have the tick from the valve guides and they also found scouring on one of my pistons. Iam now in waiting for a new engine.
I just got mine back from having the engine replaced.
Tech did a great job. You would never know the engine was out of the car.
New engine sounds and runs great.
Tech did a great job. You would never know the engine was out of the car.
New engine sounds and runs great.
Also the new motor comes complete with all accessories and the new clutch setup with the revised spring tension.
New clutch is not soft but easier then my original and no chatter!
New clutch is not soft but easier then my original and no chatter!
new motor
If the valve seat fell broke and fell out it could do some serious harm to your piston so yes the defective head could have caused this.
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