Mechanical advance

[Anonymous]

At what RPM should the mech advance start? I have a 67 distributer in my 66 and it seems the advance starts at about 600 rpm. I have a hard time setting the timing/idle since the advance is starting at basically idle speed. I also have a problem with the engine running on when I turn off the key. I have to set the idle below 500 to keep this from happening. Is my mech advance starting to early? :

 

[cfmustang]

Sounds early to me, but I'm sure that there are people with far more experence than I that can say with certainty.

I also believe that you can control how early the mechanical advance starts and finishes by changing the springs inside the dizzy. It is based on the stiffness of the spring.

Is this an old distributor? Perhaps the springs are old and lost their, well, spring.

 

[Anonymous]

It is an old distributer...From a friends 67 Mustang that he replaced the 200 with a V-8. It already had a Pertronix so I thought I would use it in place of the Load-a-matic that the 66 had. I have a duraspark that I think I will try...Just delayed using it because I will have to buy a new set of plug wires.

 

[Anonymous]

I recently re-read the section on distributors in the Shop Manual. You can easily change the tension on the spring controlling when the advance begins. However, I have yet to do it on my distributor. There is a hole in the base plate of the distributor. Apparently you can stick a screwdriver through the hole and bend a post or tab residing under the plate that the spring connects to. Bending it toward the center of the distributor decreses spring tension and decreases the rpm where the weights begin to kick out & affect timing. Bending the tab outward increases the tension and the rpm at which the ccentrifugal advance kicks in.

 

[Anonymous]

I looked in my 68 Ford manual and found the info you mention about adjusting the advance spring. I think I'll give that a try before switching to the Duraspark. Thanks