Hello,

Anyone experienced preignition at an idle.

On this one I've bumped the compression, intake & head ported, 500lift cam, dual springs, larger valves, webber carb, & header, I think that's about it.

I've tried richening the idle circuit, raising the octane, the timing has been set everywhere from +4 to + 24 with not much improvement. Can too much advance in an cam gear cause this?

This is the first one I've built with quiet exhaust, maybe they have all been doing it??

Any ideas would be greatly appreciated, I really don't want to knock the rod bearings out of it.

Thanks,

McQ