1 melted piston
 

I am in the process of rebuilding my port engine. Gen VI 502 carb motor.
Things are going well except I would like to be certain that I don't re-create the same issue that caused the need for the build.

The last cylinder on the port side had a melted piston. It was on the very edge as to where the ring was visible and a hot spot in the center of the same piston. All other holes looked fine.
Besides the obvious such as fuel pressure, the carb(which I've purchased a new 750 Dbl pmpr), is there something specific that I should pay attention too?
Everyone on here has been a great help, your thought are appreciated. Thanks,
Alex

timing

good gaskets

Are the jets in the carb the right ones ?????

Hi.
problem sounds familiar...:rolleyes:
jets...timing...higher than stock octane in the gas.
sounds like it's leaning out/pre-igniting...plenty of high octane, well distributed should prevent problems (as well as well matched, application sensitive parts)
just some thoughts..
c

parts
 

So far my plans/parts aquired are: Pro-comp alum. heads 115cc, roller rockers, crane 168731 roller cam, new 750 Cfm, althogh that may change based on what I've heard on this forum. I've been told that my stock intake is sufficient for the mild build that I'm doing and Gil, Hp500 manifolds with 16 inch low risers.
All thoughts are much appreciated.

A 750 is a little on the small side for a 502, what was wrong with your old carb?

If you are rebuilding the engine, make sure you set the quench to .037-.038". It will give you good insurance against problems caused from lean and timing issues. Combine that with alum heads, inconnel exhaust valves and cometic head gaskets and you should have the basis of a good running blower motor.

BT :cool:

Last cylinder on port bank is #7. Probably had crossfire from the #5 plug wire, causing severe preignition. Make shure your wires are loomed so that #'s 5-7 and 4-8 on the other bank cant touch each other.

Meth injection call rudy @ ICE
302-367-4962
good luck