Mopar Proformance Distributor

NiceFishEh said
Dave:

I tried timing my stock 340 using a vacuum guage and ended up with around 26* initial. It took it all, idle smooth and sounded real strong. Brought the idle down to 825 rpm. Took it out and tried it...as suspected...it pinged quite a bit.

I kept backing it off until the ping went away. It's around 23* initial now. No starting issues and no ping.

I find more and more articles about not to trust 38 year old balancers, and how marks can be way off.

340's are internally balanced. Do they have a rubber ring? I don't remember seeing any rubber...thought it was solid steel. If it is steel, it could not slip.

My dist was set up on a machine. It has 19* mechanical with 34* total at 3500 rpm.

These are just numbers, are they not?

Regardless of what the initial is, the 19* in the mechical portion does not change...it's all relative, right? This give me a total of 42*.

What I do like about using a vacuum guage, and since no two engines are the same, is it take a lot of things into consideration like engine wear, cam duration, carb setting etc....

Comments...

If you have 19 degrees in the distributor and the intial set at 23 then your total is 42 as you stated. Yes the factory balancer has a small layer of rubber between the inner hub and the outer ring, that is how it takes out harmonics. The external balanced engines will have a weight attached to the back side of the outer ring.

Yes they can slip, the only way to check if it has accurately is; Buy, borrow or steal a degree wheel and piston stop. Mount the degree wheel to the end of the crank, put the piston stop in #1 and mount a piece of wire to the block to use as a pointer on the degree wheel. Turn the engine over by hand until the piston contacts the stop and record the number of the degree wheel. Reverse the rotation by hand until the piston contacts the stop from the other direction. The mid point between the two numbers is TDC and the timing mark on the balancer should be lined up with that point on the degree wheel.

If your marks are accurate and are truely at 42 degrees total then you need to take some timing out of the distributor. If it's an MP use a 12 degree spacer (or if you don't have the kit use a protractor glued to an old rotor and a wire as a pointer on the housing, you will want 6 on the protractor, distributor runs at 1/2 the speed of the crank so the degrees in the distributor are measured at 1/2).

Also, you will need stiffer springs when you reduce the advance in the distributor if you want it to stay at 3500 rpm for being all in.