MSD Distributor / Timing Problem

[pusherfans]

I have been working on getting my timing set for a couple hours now and I think I am either going crazy or there is a problem or something I am not aware of.

I get the enigne warmed up
I set the idle mixture to around 14:1 (I am using an O2 sensor)
I get the idle to be around 1000 RPM (big cam)
I looked at the timing and it is 20 degrees (engine builder recommends this)
5 minutes later, the idle drops about 50-150 rpm
I check the timing and it is now 10 degrees
I increase the idle back to 1000
still 10 degrees
I set it to 20 degrees and lock it in again
I rev to 3200 and get onlt 28 degrees
Back to idle, but now it's around 1100
timing is at 24 degrees

no matter what I tried or what springs I use, it never comes back down to the set timing. and it takes about 5 minutes for it to come down any degrees

I called MSD and they had me check the bushings under the weights and that it all moves freely, and it all moves just fine and I even dapped a little oil on the pivit areas and no difference.

Do I just have a bad distributor (only 800 miles on it)? Anything I'm missing?

[DAVID GAGNARD]

Originally Posted by pusherfans

I have been working on getting my timing set for a couple hours now and I think I am either going crazy or there is a problem or something I am not aware of.

I get the enigne warmed up
I set the idle mixture to around 14:1 (I am using an O2 sensor)
I get the idle to be around 1000 RPM (big cam)
I looked at the timing and it is 20 degrees (engine builder recommends this)
5 minutes later, the idle drops about 50-150 rpm
I check the timing and it is now 10 degrees
I increase the idle back to 1000
still 10 degrees
I set it to 20 degrees and lock it in again
I rev to 3200 and get onlt 28 degrees
Back to idle, but now it's around 1100
timing is at 24 degrees

no matter what I tried or what springs I use, it never comes back down to the set timing. and it takes about 5 minutes for it to come down any degrees

I called MSD and they had me check the bushings under the weights and that it all moves freely, and it all moves just fine and I even dapped a little oil on the pivit areas and no difference.

Do I just have a bad distributor (only 800 miles on it)? Anything I'm missing?

I've pretty much had the same thing with mine, car doesn't get used much and I find the MSD distributor is prone to moisture build-up and rust inside.... I generally take mine apart once a year and clean it out real good and put a dab of oil on all the moving parts/springs, not much,just a dab, seems to help......

You might also change your springs, sometimes when a spring loses tension, it takes forever for the timing to return to the base timing as you stated yours does.

Your not alone...........

My MSD unit has 22 degrees built in, so I only worry about total timing, my engine runs best at 32 degrees total, so that's where I set it at 3,000rpms, and let the idle timing fall where it may, in my case 10 degrees........

Your engine builder recommended 20 at idle, what was his recommendation for total timing?????

What are the specs on your engine.....?????

David

[pusherfans]

The builder wants to see 40 degrees at 2500.
It's an FE 527 with a 633 lift cam and around 250 duration

I did dab oil and all is working freely in the distributor

[DAVID GAGNARD]

Originally Posted by pusherfans

The builder wants to see 40 degrees at 2500.
It's an FE 527 with a 633 lift cam and around 250 duration

I did dab oil and all is working freely in the distributor

Mechanical advance or vacum????????????

never had that problem with vacum advance,only mechanical ones.....

check everything closely, I found that by moving the "arms/levers" that the springs attach to, I had small spots of rust under them, took it all apart and cleaned the rust of with a small brass brush and put a drop of oil and put it all back together, things worked a lot better......

also check your "stop" bushing and all other parts for binding....

definetly go with the builder recommendations on timing.....check your paperwork, you can change the springs for the timing to come in faster or slower and change the stop bushing for more or less total timing..............

They usually come with the heaviest springs installed,I usually end up with the middle tension springs to make it work like I want it to....

David

[pusherfans]

Okay, I took your advice and went back out there, set the timing at full advance (3000 RPM just to be safe) and at 38 degrees. (builder wanted 40, again I put it lower just to be safe). And set the idle again at 1000 RPM (975-1050 really) F/A ratio at 14.0-14.5 at idle and cruised for 20-30 minutes. It runs awesome! instant throttle response, idles fine and no run-on. But it's a cool day, let's see what happens at 80-90 degrees out. . . but it looks like I am down to fine tuning now.

I have mechanical advance only, a Holley HP4150 Ultra with 73 main jets, all else is stock, the way it came out of the box.

Thank you for the idea and it's good to know it's not a bad distributor, but a "characteristic". Perhaps because it was built for drag racing and not cruising around town?

[Rick Parker]

If you have the very weakest springs in the distributor, it will not return the flywheights when the RPM's drop, causing the timing to stay somewhat advanced and your idle to be higher than you set it a few minutes before, and the idle will "Hunt". Put a dab of dielectric grease on the flywheight pivots and on the pads underneath the weights, if the weights have corrosion or light rust, use a wire brush and WD-40 to remove the rust. The weights must return to their "Home" position or the timing will remain advanced.