I thought i had a pinging problem, but i am not sure. I get this "pinging" from about 4300-4500rpm, but it occurs irrespective of the load on the engine. I think it may be some kind of harmonic vibration or maybe a lifer(?) I have tried changing my timing and centrifugal advance springs whcih seems to have no effect. I am going to re-check the valve lash this weekend. I looked at a couple of plugs with an otoscope and didnt see any "debris." Is there any thing else that could be causing this???

 

Merf,

Even at that RPM, you shouldn't experience detonation at no load or closed throttle. Vacuum created in the cylinders would just about completely eliminate the conditions for detonation, unless your timing is wicked advanced. It sounds as if you've already addressed that possibility, so I'd lean toward something mechanical, like a valve train item or flywheel/flexplate/converter. The pistons, rods, bearings, and crankshaft would create noise more related to load than RPM, while the valve train and other items mentioned typically make noises related to RPM regardless of load.

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Later,
Vader
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"Make Me Bad"
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