Advance Wrong--What to look for?

Paulporsche · 10-31-2008, 01:14 PM

A mechanic who was recently working on my car said I am getting full advance @ 2000 rpm. I understand this should not happen until about 3500 to 4000.

If I open up the diz what should I be looking for? Broken springs? Dislocated weights?

I should be able to see a broken spring or a weight that has come loose. What else could cause this? Can I tell by look or feel if something is worn or fatigued?

Steve@Rennsport · 10-31-2008, 01:44 PM

Paul,

You should look for a broken or missing spring on one of the weights.

Remember, there are two springs in these things: one is a light spring and the other is stiffer. Both are required for proper operation.

Paulporsche · 10-31-2008, 07:11 PM

Thanks, Steve.

If springs are intact, is there anything else that could cause this?

Is there any reason why someone would deliberately ramp up the advance this quickly?

moneymanager · 10-31-2008, 07:48 PM

Not if his brain was intact!

Steve@Rennsport · 10-31-2008, 10:19 PM

Quote:

Originally Posted by Paulporsche

Thanks, Steve.

If springs are intact, is there anything else that could cause this?

Is there any reason why someone would deliberately ramp up the advance this quickly?

Either someone put in a very aggressive advance curve, or the weights may be stuck,........

Sounds time to remove the distributor and disassemble it to clean it up and make certain that its working properly. The latter aspect should be done on a distributor machine.

mb911 · mb911's Garage

polarity backwards on MSD? done that once or twice with the same results

Paulporsche · 11-01-2008, 04:35 AM

moneymanager,

LOL! Can never rule that out.

Steve,

Thanks again.

Ben,

Interesting. I thought I read somewhere that there can sometimes be issues between MSDs
and the dizzies, but I couldn't remember what they were. I'll have to check out the polarity. Thanks.

stlrj · 11-01-2008, 05:37 AM

[QUOTE=Paulporsche;4273744]A mechanic who was recently working on my car said I am getting full advance @ 2000 rpm. QUOTE]

As long as it does not ping, consider yourself lucky. All in at 2k will enhance low end torque and throttle response.

Paulporsche · 07:05 AM

stlrj,

You might be on to something. This setup was prepared by Rudy Bartling (Google him if you don't know who he is; kind of an older Grady Clay w/ a German accent!) who's been working on these cars since the late 50s. I've been using it for something like 17 years w/o problems. The MSD has been on for 3 years. My mech said he found no broken springs.

Ben,

When you say you had the same results, you mean that polarity made no difference to the advance curve?

Steve@Rennsport · 11-01-2008, 08:15 AM

Paul,

If the polarity of the wires that trigger the MSD unit is reversed, the advance curve is about 15degrees off.

This is a common occurance so its something to check.

The green coaxial distributor trigger wire should be connected as follows: center conductor to green MSD wire & violet MSD wire to the shield.

stlrj · 11-01-2008, 10:51 AM

Quote:

Originally Posted by Steve@Rennsport

If the polarity of the wires that trigger the MSD unit is reversed, the advance curve is about 15degrees off.

.

That far retarded would have been noticed by your mechanic since your engine would barely idle if it started at all.

mb911 · mb911's Garage

Quote:

Originally Posted by Paulporsche

stlrj,

You might be on to something. This setup was prepared by Rudy Bartling (Google him if you don't know who he is; kind of an older Grady Clay w/ a German accent!) who's been working on these cars since the late 50s. I've been using it for something like 17 years w/o problems. The MSD has been on for 3 years. My mech said he found no broken springs.

Ben,

When you say you had the same results, you mean that polarity made no difference to the advance curve?

no I had way to much advance at low rpm all do to polarity