If your exhaust was quieter, I might be able to tell. Get the part number off the distributor you bought. Should be 7 digits, right on the circumference of the distributor, just below where the cap goes on.
1969 Buick 350-2, See below, 30-34* of maximum mechanical advance at 4600 RPM. This distributor was supposed to be timed initially at 0* (TDC). If you are running more initial, that is why it is pinging.
Well, I fiddled with it quite a bit today. Can't seem to figure out why it's pinging. Adjusting timing from 10 to 0 where it's supposed to be at didn't seem to affect it at all. The only thing that does seem to affect it is messing with the dwell. It seems the lower I set the dwell, the less it pings. If I have it set at 30 it pings really bad.
Oh, yeah. I reset the timing after I messed with the dwell. Didn't seem to help. Before I hooked up my timing gun and dwell meter I was at roughly 20* dwell and 12* BTDC. That setup gave me less pinging than 30* dwell and 0* TDC. I also tried 30* dwell at 10* BTDC since that's what's on the sticker for stock timing. That didn't really make much a difference. Maybe slightly.
My guess is I'm not getting enough fuel. Might need a carb rebuild and tuning. I'm thinking a bigger power valve, jets, or nozzle on my carb might do the trick. Or maybe some combination of the 3. As far as I know everything on my carb is what it came with stock. It's a Holley 4412-3 500 CFM 2 barrel.
I think you need to look at the specs for the 1111938 distributor you are using. It has 30-34* of maximum mechanical advance. The reason for the range of 30-34 is that due to the manufacturing tolerances of the day, that particular distributor you have can have 30, 31, 32, 33, or 34*. If you run 12* initial advance, you will have 12* + 30-34. You will have 42-46* of advance when you nail it. No wonder it is pinging. That is why you must use some light springs to set the total advance to 32*. Your initial advance will then be WHAT IT HAS TO BE for that distributor. You HAVE NO CHOICE of initial advance unless you change the amount of mechanical advance.
Your timing sticker is completely irrelevant now. It only applies if you have the distributor that the stock engine left the factory with. With the 1111938 distributor you are using, your initial advance will end up being around 0*. Anything more will over advance the timing at higher RPM, and it will ping or detonate. Be careful, you will damage the engine eventually.
That definitely makes sense. What doesn't make sense to me is even when I've got it timed at 0* initial it pings pretty bad. 0* initial should put me close to where I need to be, so I was assuming it shouldn't be pinging like it is. I've got that curve kit ordered, though. I really hope it helps the pinging once I set total timing. I just can't wait to get this thing back on the road. I really do appreciate all the help, though. Thanks a ton, Larry.
What do you have the vacuum advance hooked to? 68-69 should be manifold vacuum. Not ported. Try running engine with vacuum advance plugged. See if it changes anything
I have it plugged at the moment, but normally I have it hooked to the port on the throttle plate of my carb. What would be the best way to hook it to manifold vacuum? Probably a dumb question, but I'm still learning how to work on this type of stuff.
Finally got that vacuum advance kit in the mail. I installed lighter springs so my mechanical advance is fully in by about 2800 RPM. With my mechanical advance set at roughly 32* I'm still getting pinging. It seems milder, but I'm not 100% sure. Could this distributor have too much mechanical advance for my engine? Maybe I need to do what Sean suggested and install a bushing kit.
I'm not sure of what you are hearing. I can't hear it over your exhaust. Once you have the maximum timing set to 32*, put the heavier springs back in and road test it again.
That video is pretty old. I'll try recording it again tomorrow with my newer phone. Might be able to hear it better.
Still haven't got around to re recording the sound I'm hearing, but the more I mess with it, the more I'm thinking it's a lean backfire through the carb. No matter what I do with the timing it doesn't make any difference to the sound. I'm thinking the carb isn't properly tuned, or it just needs a rebuild. I just don't know if I should put bigger jets or a bigger accelerator pump in it. Or maybe both. Edit: The heavier springs made no difference. Forgot to mention that.
