What does detonation/ping sound like exactly.
I've had my 65 for almost five years now and never had to mess with the timing. It's always ran great so I left it alone. Over the summer though my dizzy hold down bolt worked loose and the timing slipped. I borrowed a friends timing light and set it at 12* at idle with vacuum advance plugged. I noticed a rattling noise the other day when driving slowly through a parking lot. It occurred only at off idle when driving slowly. Now that my ears are tuned for it and it's windows up season I'm hearing it pretty regularly, again in parking lots and slow low speed traffic. It doesn't seem to do it when your giving it a lot of gas only when the throttle is cracked. I tried retarding my timing back to 6* and went to 91 octane fuel with no change. The car seems to run better at 12* so I went back to that for now.
I searched this forum and Google and most people say detonation sounds like a spray paint can rattling. This noise is more like a catalytic converter heat shield rattling, of coarse my 65 has no cats. It's also very hard to hear. While cruising the other night I asked my wife if she could hear it and she couldn't. How loud is engine ping? Too use the spray can analogy, does it sound like the can is being shaken slowly or very rapidly? Is obvious when you hear it?
The worst part is I'm not 100% sure it has anything to do with timing, it could just be a normal rattle this old girl makes and I just never noticed until I was really listening. The windows are down more than half the year too, many of the rattles are drowned out by wind noise. I'm just nervous about ignoring it and having major problems down the road. Sorry about the long post and thanks for your help.
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