Decided to get a little more serious about my ignition timing so I bought a fancy new digital timing gun with built in tach ;) What RPM do you guys think I should go to before I check?
Ughhh... rpm wont matter if your setting base timing.
Uhhh....should I have used a bigger font for total?
lol, oops
2k-2.5k although 1500 should be just fine and on the mark
The 84 shop manual checks timing advance at 2500 RPM.
First they check it at 2500 RPM with the vacuum advance disconnected to check the centrifugal advance.
Then at 2500 RPM with the vacuum connected.
Unfortunatly they refer to the "Service Performance Manual" for what the advance should be for a specific engine calibration.
I do not have this manual.
32*-34* total advance at 3k rpm should be good.
Don’t know our cars well I just set base at about 14-16 but my stock SBC 350 in my enduro circle track car I set about just over 30 degrees at about 3000rpm that’s w/a carb and vacuum advance disconnected. Some guys at the track power tune w/the vacuum advance hooked up.
I know this isn’t helping but I am interested in what guys have to say on our 5.0s and EFI
Well shop manuals for our cars would be incorrect because of your HEI distributor. Do you have the paperwork on that distributor? What rpm do the weights fully open? I would pop the cap/rotor off and note the springs and try and find pictures of the various springs for the HEI. Might want to get a re-curve kit and play around.
If you feel a mid to low rpm bog or the engine rpm gain isn't smooth then you will need to change springs. The same if your engine pings for a second or so gaining rpm.
And rpm would matter if he was setting base timing on a vacuum advance distributor ;) If he sets the base timing at 3k rpm (silly) with a TFI setup it wouldn't, but with that distributor he would be in the mechanical advance mech.
Setting up a distributor advance curve is totally different for best performance vs getting best fuel economy at cursing speeds...Before going "Willy Nilly" you need to know how much mechanical advance is in the distributor...
Now assuming performance, disconnect the vac and forget it... Set the timing to Zero(or dial it back to zero with your fancy light), and record how much advance you have at what RPM... Generally you want total advance "all in" by 3200-3500 RPM... This may involve playing with the advance springs inside the dist, as usually a stock setup doesn't have it all in till past 4500...
Tom
I do have a recurve kit, in fact today I took it out and put the Procomp back to stock. I got that distributor off ebay and it didn't come with instructions and the Procomp site is a waste of webspace but I figured that since it was designed for a Ford smallblock it was probably set up better than the Moroso kit I had been screwing around with. Today being thanksgiving I don't have time to get more detailed with it but thanks for the info.
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