Mechanical Advance

[Bort62]

I've got a problem with my mechanical advance.

It's a DSII, and i've welded the advance slot down to limit to 10*.

This all worked great a few days ago. At that time, I had the whole setup running with the pink resistor wire. Because of this, I had to set the idle above 1000 RPM or the voltage to the module would drop below 9v and it would not work (and the car would die). I went in and removed it to get a full 12v+ at the module/coil. At that point, I was able to lower the idle to about 500 rpm (screw on my YF all the way out).

At anyrate, that seemed great, but the advance stopped working properly. In fact, I was getting about 10* of retard w/ rpm. It was suggested on here to reverse the polarity of the reluctor to the module. I did some double-checking and discovered that I did have it backwards, so I reversed it. That stopped it from retarding w/ rpm - but it still doesnt work right.

Now, i've got it so that it is set at 10* initial. When I rev it up, I get about 4* of mech advance. Then - if I keep revving it up - it falls back to 10* (initial) - the mech advance goes away.

I don't know precisely what RPM because I can't see the tach and check the timing at the same time, but it jumps up right off idle and falls back around 3k rpm or so.

So, the base question is - why is my mech advance not working ? I have taken the distributor apart a few times and everything seems fine. I also locked out the vac advance, so that isnt a factor.

 

[wsa111]

Ian, what are you using as a trigger, the ds2 to a msd or a gm module???

If your deal worked for a while, then it must be a module problem or is it a duraspark signal condition.

Try a different timing light, i know msd does not recommend a timing light with the advance checker. However i have seen timing lights with the advance checker work fine with the msd box.

What system are you using???? Bill

 

[Bort62]

Originally, I was using a GM 4 pin. I switched to MSD 6 AL and have observed no change.

I also tried a different timing light, and it shows the same information.

 

[wsa111]

Ian, i had a problem when i first installed the MSD-6AL.

The harness i purchased from msd had the wires crossed fom the DS-2 to the MSD. I swapped polarity & that solved all my problems.

But you said you have already done that.

Heck all i can say is swap some componets from a working setup & you will find the problem.

The reversed polarity really caused many problems, stalling,timing mark jumping all around, rough idle to backfiring.

I assume you have the MSD hooked up to the DS-2 using the MSD harness??? Bill

 

[Bort62]

No, I cut and spliced it myself.

I have had the same problem with both the MSD and the GM module.

I did have the problems you describe before with the GM module before I swapped the polarity.

If I was only getting the 4* I would go grind off a little of what I welded, but the fact that is advancing, and then going BACK really confuses me.

 

[addo]

I believe the problem lies in the breaker plate. After a certain speed, the camweight is no longer pushing the upper shaft around, and it begins to retract. Careful examination of the plate - by manually operating the cam weights - should reveal the cause.

 

[LEROY POLL]

BORT62


.....SOUNDS LIKE THE FLYWEIGHTS ARE NOT WORKING. DID YOU TAKE THEM OFF WHEN YOU WELDED THE STOPS ? YOUR ADV. IS ONLY BY THE WEIGHTS. SO THERE MUST BE A PROBLEM THERE.

.....CHECK THE WEIGHTS BY MANUALLY SPREADING THEM OUT. SEE IF THEY ARE ADVANCING THE CORRECT WAY.

.....YOUR LAST POST TIME SAID 10:55. IT'S ONLY 8:00 HERE. THIS MUST BE ON A DIFFERENT TIME ZONE.

LIVE IN GRACE

 

[Bort62]

Leroy, I am in San Francisco right now... the board is on Eastern Time.

Everything in the dist seems to be working fine, but I guess I will take it apart again...