I'm still trying to narrow down why my engine is smoking and I remember the last time I posted here I commented that my car didn't smoke upon cold startup, but I found that it actually does, which many have said may point to bad valve seals. I haven't had the opportunity to check on those yet, so before I do I just wanted to see if there is any relationship between bad seals/guides and engine ping. It seems that no matter how much I mess with my timing I just can't get it right. When I find what seems to bring optimal performance, the engine pings on lean-in, so when I tinker till the pinging stops, the performance just plain sucks. I thought that maybe when it's sparking just right it's making the valve shake due to a bad guide? It seems to work out in my head, but then I haven't seen half the things you guys have seen. Any feedback would certainly help.

Yes, it is possible. Oil reduces the gasoline's effective octane rating. I have no idea how much though.

Another possibility is the accumilation of carbon in the combustion chamber, raising the compression to an acceptable level relative to the ignition timing.

My .02...

You are on the right track...as Silver69Camaro pointed out, oil does reduce the octane rating of gasoline so it can "ping" at lower temps/pressures than normal. Add to that the oil residue / carbon that starts to coat the piston/valves, etc. It can create hot spots that also lead to pinging. From what I have seen, and a couple of old engines that I have trashed...it's a downward spiral just doesn't get any better. The pinging will probably take out a head gasket if it gets too bad or goes on for too long.

You can try to set your timing back to normal, run higher octane grade gas and a cooler t-stat. These are kind of bandaid fixes that work a little. I have not tried the "motor vac" system which is supposed to help clean out carbon. I think I read of someone letting the engine suck up walnut shells, too? Others sware by a good soak in ATF through the spark plug holes. I did soak an old piston in ATF just to see what would happen...it did remove some of the carbon but a lot stayed too.

The ideal solution is at least a budget rebuild with boring/honing and new rings to stop the problem.

Good Luck

Is it pinging on part throttle or on full throttle? If part throttle, you may have too much vacuum advance. Just a thought...

GM makes a top end cleaner that works well. I have seen it reduce pinging dramatically. The stuff is pretty mean. Definately want to change the oil after use.