Total Timing Question
Thread Starter
Intermediate
Joined: Jun 2007
Posts: 49
Likes: 0
From: Cameron Park CA
Total Timing Question
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?
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?
Drifting
Joined: May 2006
Posts: 1,425
Likes: 0
From: Seattle Wash.
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.
Last edited by 427-390; Sep 6, 2007 at 07:29 PM.
Thread Starter
Intermediate
Joined: Jun 2007
Posts: 49
Likes: 0
From: Cameron Park CA
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.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,117
From: Crossville TN
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.
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.
Race Director
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
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?
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?
Thread Starter
Intermediate
Joined: Jun 2007
Posts: 49
Likes: 0
From: Cameron Park CA
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.
Tech Contributor
Joined: Aug 1999
Posts: 14,377
Likes: 6,377
From: At my Bar drinking and wrenching in Lafayette Colorado
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.
Instructor
Joined: Jul 2007
Posts: 245
Likes: 2
From: Hope Indiana
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!
I think I want my timing to be all-in around 3000 rpm (street car), but where do you recommend setting total timing?
Thanks!
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Tech Contributor
Joined: Aug 1999
Posts: 14,377
Likes: 6,377
From: At my Bar drinking and wrenching in Lafayette Colorado
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.
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.
Drifting
Joined: May 2006
Posts: 1,425
Likes: 0
From: Seattle Wash.
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.
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.
Racer
Joined: Jul 2007
Posts: 444
Likes: 0
From: Roselle IL
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*?
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*?