79swtl82

Hi All,

I adjusted my timing per Lars's timing Info. Set it so total timing is 36. Put everything together and checked the initial timing and it is now at 20. Is this okay? The car seems to run smoother but I'm concerned that the initial timing is set to high. Why would it be so high?

427-390

You can, for the most part, not worry too much about the initial timing. Total timing is what you are after. You should be dialed in at 36* at around 2700 - 3000 RPM with that vacuum advance disconnected. What is your car idling at while in neutal or park? If the RPM's are too high, that could lead to higher then normal initial timing. Vacuum leaks are another source as well. Others with more knowledge then I can explain in detail regarding the initial timing aspects.

79swtl82

I took it out for a test drive and it was pinging a little so I set the timing back 2 degrees to 18. It sure drives a lot better then it did with the total timing set at 36. It has a much better response at the throttle.

7T1vette

I'm not sure what you mean by "total timing". Do you mean maximum mechanical timing? Or do you mean mechanical timing plus vacuum advance?

Lars recommends that you work with the distributor...advance can disconnected....playing with springs, etc. to get maximum mechanical timing of 36 degrees somewhere between 2500-2800 rpm. Once you get that established and hook up your advance can [assuming that you want and/or have one], "total timing" may be something else as rpm and intake vacuum vary. If you set the mechanical advance at 34-36 degrees, as Lars describes, your car should have about 10-14 degrees of advance at idle speed with the vacuum advance can reconnected. If you are showing 20 degrees at idle, I would think you have the wrong advance can for your engine or you've set the mechanical portion improperly. Just sounds like too much advance at idle to be correct.

...Roger...

Your right on the money if your dist. is stock.Your dist. has 16* mech advance at 2000rpm.36*total minus 16* mech = 20* initial.....Your vac. can has 10*@ 8"...for Maximum advance of 46* I'm a little suprised your pinging with that setup. Poor fuel,engine running hot,heat riser stuck,carbon buildup?If you backed it up 2* and it stopped go with it if it runs good.

79swtl82

The distributer is stock and this is the best it has every ran so I'm going to leave it where it is. I do have a bad catalytic converter that has been overheating but I don't know if that would cause the pinging.

lars

Your timing and setup method is correct - good job! The initial timing you end up with depends on the length of your advance curve and on whether or not you're getting a little bit of centrifugal advance coming in at your idle speed. It's not uncommon to have a 16-degree advance curve, although most are in the 20-24 degree range. Initial timing anywhere from 12 to 24 degrees will run fine as long at total is limited to 36 (or less, depending on the engine's needs). Good job with the setup - it should run well like that.

nw2571

Lars, I don't want to hijack the thread by any means, but what is your recommendation for setting timing on a non-vacuum advance distributor? I bought my car recently and it's got a non-vac Mallory Unilite. I plan on changing to a vac advance some time in the near future, as I understand that the vacuum advance will help with fuel economy.

I think I want my timing to be all-in around 3000 rpm (street car), but where do you recommend setting total timing?

Thanks!

lars

Vacuum advance has no effect on Total Timing setting - there is no vacuum at WOT, so a vacuum advance distributor acts as a non-vacuum unit at WOT. Your total timing on your non-vac distributor is, therefore, the same as for any other distributor: 36 degrees.

On your non-vac unit, run a short curve so you can get a fairly high initial timing setting with the 36 total. This will help idle quality and will make the engine run cooler around town. I like to shoot for 18 to 24 degrees of initial timing on the non-vac units while limiting to 36 total, as on all distributors.

427-390

Total mechanical timing with the vac can disconnected is what I meant, as noted in my earlier response.

nw2571

Thanks Lars. I guess it's off to Jegs for a set of springs for my Mallory!

lars

Springs won't change the length of the curve. You have to change bushings to change the curve length.

lr172

Lars,

I have heard about bushings before, but I am not sure where these are. I rebuilt my dsitributor and got some new springs and weights. I decided to try first with the old weights and new springs. The pins had worn, wo I pressed them out, rotated them 180* and put them back. I only get 16* of advance from this set up. There didn't seem to be room for a bushing inside the hole on the weights. The fit over the pin was fairly snug.

Can you give a little more detail on the bushings that will help get 20-22* of advance out of this set up? It is an HEI distributor.

I have the Mr. Gasket advance kit. If I install these weights, will I get closer to 20*?