okokok... Compression Question

[Earlsfat]

Originally Posted by Morley

Depends on how deep the "pitting" is. But I was talking about actual holes through the piston tops.
Valves going up into the sleeves? You mean up into the guide? That would mean you sunk the valves, another sign of detonation. I would definately get the engine checked to see what compression ratio you are running. If it is over 10:1 you'd need to run race gas all the time to keep from ruining the engine.

Pittiing was less than a 1/16"... probably closer to 1/32" or so.

Yeah the valves were going up past the seats.. I guess because the edges were burnt pretty badly.

The octane level doesn't effect the leaness / richness of the mixture?

[Morley]

Originally Posted by Jimsfat

The octane level doesn't effect the leaness / richness of the mixture?

No, Octane only affects how fast the gas burns. A lower octane gas will burn faster which can cause detonation (it explodes under the higher compression). Higher octane gas burns slower. Using a high octane gas in a low compression engine isn't good either, but the worst that will happen is lower mileage and possibly fouling the plugs.