I have the MSD 85551 adjustable mechanical advance distributor, and I was wondering how to determine at what RPM I should have full timing come in. Is there any theory behind this stuff, or is it all guess and check?? Also, what should I do to determine what total timing amount I should use, and what my base idle advance should be?? ANY help would be great. This stuff is Greek to me, lol. Thanks in advance.

 

Go to your local parts store and pick up the Moroso spring kit. I contains three different tension springs that you can use to alter the timing curve.

The only sure fire way to get a kit like that to work properly is trial and error.

Start with the middle springs and go from there.

If you don't get knock, go lighter (less tension) and drive it again. If you do get knock, go heavier.

Just remember the springs only change the rate of the curve (i.e. how soon total advance comes in). It doesn't add or remove anything from your total timing. Get that set first. You can also alter that in order to achieve the best curve with the least amoung (i.e. NONE) of knock.

As far as mixing the springs...... if you get some knock, try using one heavier spring on just one of the weights while leaving the medium spring on the other. See what it does and go from there.

 

Thanks for the reply. The distributor actually came with a set of springs and stop bushings. What about base timing, how do you know if you have that right on or not? Thanks again.