What is the proper method of checking/setting the total timing advance on an hei distributor? What range works best? I've heard 32-36 degrees total

 

There is no set rule for what total works best since there are so many variations from engine to engine. Normally anywhere from 32-40 can be used. Once the best total timing is located, anything else you do to the engine will not affect where the engine likes it's total timing. I currently have my engine at 37* but I don't know if it makes it's best power there. My timing is locked at full advance so I have no ignition curve. If you move your base timing, you also move your total timing unless the distributor is recurved.

Timing should be at full advance by 3000 rpm. You'll need either an advance timing light or a degreed balancer to check it. Bring the rpm up to 3000 and check the timing. If you bring it up to 3500 and still get more timing then your total is coming in too slow.

How fast the timing advances is controlled by the springs. A lighter springs will allow the weights to open up sooner. How much total timing is controlled by the weights and cams inside the distributor. You can mix and match parts to get exactly what you want.

The best way to do it is by pulling the distributor and taking it to a shop that will recurve the distributor on a machine.

 

I have an advance timing light. I guess what i should have asked is how you check it. Do you dial the light in and throttle the engine? To what rpm or just until it quits advancing? I don't know of any shops locally that would have that kind of equipment to recurve the distributor so I was going to attempt to do it myself.

 

You can graph your own curve.

Start at an idle and check the timing. Go up 500 rpm and check the timing. Keep doing this 500 rpm at a time until the timing stops advancing. A totally stock distributor may stop advancing the timing at 5000 rpm. That's why for performance use, you chould always recurve it. Use the advance feature in the light to aim the timing mark on the TDC mark every time.

This will tell you the ignition curve of the weights and springs. The vacuum advance isn't a part of this. Vacuum advance is used for part throttle operation under load. You should always disconnect it while checking timing. Buy one of the cheap recurve kits or go to your local junkyard and rob different weights and springs. Like I already said, you can mix and match parts. One light spring and one heavy spring to change how fast the curve advances. 2 different weights to get the total you want. Different cams etc.

Keep changing things around until your graph peaks out around 3000 rpm and your total advance is where you want it. Remember, if you change your base timing, your total will change so find out what base timing you want to start with.

By experimenting with different weights, you can determine how much total you'll get from different weights. At the track you can then quickly change the weights to change your total timing. Once your base timing is set, changing the timing by turning the distributor to change the total is the wrong way to do it although everyone does it.

Since my timing is locked at full advance, my base timing is also my total timing. My ignition has a start retard so the timing can be retarded up to 20* to start the engine. When I adjust my total timing, I can do it at an idle. This is only something you want to do on a full race car. Street cars need a timing curve.

 

Thanks! That's what I was looking for.