Timing Question Again.......
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Freshman User
Joined: Nov 2003
Posts: 38
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From: Beaverton OR
Timing Question Again.......
I've seen lots of posts regarding timing questions, but so far they have been vague(to me anyway) .I may be in good shape but i'll ask anyway.
I have a 67 with a 352. At higher rpms, freeway speeds, I get a very noticeable ping or knocking. I'm going to recheck my timing and to start probably keep it at 6 deg btdc @ 550rpms which is what the chiltons book suggests. My motor is completely stock and runs pretty smooth normally, but if I can tweak it just a little bit more and get rid of the knock i will. I there some unwritten trick or tweak that can be done that i don't know about? or is this spec the best setting to shoot for. Would this require advancing a bit more or retarding. Or is it a gas issue.
Any ideas or tricks?
Thank in advance
Senior User
Joined: Sep 2003
Posts: 238
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From: Bridgeville,CA
Check not only the idle setting but the advance. It is possible that at high RPMs you are getting too much advance and that is causing the problem. It also is possible that you a carb problem. If the mixture is going way lean at high loads then you could get pinging.
Lead Driver
Joined: Jan 2003
Posts: 9,893
Likes: 12
From: Ohio
Rev the engine to around 2500 rpm and see where the timing mark is at. Your damper will probably not have marks that high. You will need to fudge it a bit and maybe make your own marks. It should only go to about 38 degrees total timing. Any more and it will knock/ping.
For instance, if the timing marks are 1/2" apart for 10 degrees, then keep marking 1/2" increments so you can see where 40 degrees is at. It will get you close enough at least.
A lot of the guys here have installed NEW adjustable vacuum advance canisters to be able to bring it down to something close to that. One test is to unplug the advance(plug the line then) and drive it. Does it NOT ping anymore. Then that is the problem.
I went through this also. I do not run ANY vacuum advance. My intial timing is at around 6 degrees and it runs about 35 total. It runs perfect.
Larry
For instance, if the timing marks are 1/2" apart for 10 degrees, then keep marking 1/2" increments so you can see where 40 degrees is at. It will get you close enough at least.
A lot of the guys here have installed NEW adjustable vacuum advance canisters to be able to bring it down to something close to that. One test is to unplug the advance(plug the line then) and drive it. Does it NOT ping anymore. Then that is the problem.
I went through this also. I do not run ANY vacuum advance. My intial timing is at around 6 degrees and it runs about 35 total. It runs perfect.
Larry
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