Anyone here ever have their pistons machined?

txstang84 said

FD, maybe I missed the passages about your A/F ratio tuning, but 13.0 WOT is typical, but not necessarily ideal for every engine.

Did you ever dip it down to the 12.5 or so range during all your tuning?
Did you try fattening up the mixture when you slowed the timing?
Did you ever try running a colder plug?

I know I should probably re-read the original thread, but hey, you're here now

Click to expand...

With bigger jets, I had it as rich as 11.0 at WOT and it still knocked. I tried doing the changes one at a time in order to isolate the results. The only time that I was able to get it to run knock free at WOT on 91 fuel was when I backed the timing off so far it wouldn't idle without stalling. It was at 6 * initial and 20 total. This was only for testing purposes! I didn't drive it long like that.
Colder plug? I'm running a Champion RC9YC. I used to run the RC12YCs that Edelbrock calls for, but switched to the 9s to stop the run on-dieseling problem it once had.