Anyone know the ideal clearance between the dist gear and the shaft is? I think Redraif's has too much play in it, and I'm shimming it tonight or tomorrow.

 

Never thought to check it out. How will you shim it?

 

Barnett Racing sells shims for just that. Turns out the car had 2x what it should have had...Go figure. So we are hoping that finally the car will run at 10 degrees. Though we will probably bump it up a bit.

 

Rbob replied to my question about it on the Tech?General Engine board...an aluminum body distributor should be shimmed to 0.012" to 0.015" of end play. Cast iron body distributors can be shimmed to 0.005" to 0.008" of end play. Our 2.8 distributors, and most GM distributors made since the early 60s, are aluminum.

To measure endplay, you stick a feeler gauge between the upper part of the dist gear and the factory shims (they have interlocking teeth); Shannon's was about .030! You could pull back and forth on the dist gear and watch the rotor move up and down. This can cause spark scatter, which often shows up as timing that jumps around a lot. Moroso makes a shim kit for all Gm/Delco type distributors to tighten the endplay (ours was less than $5 with tax); Shannon's is now set at .012. This is an easy fix, esp if you're doing a distributor rebuild anyway.


Timing has always been an issue with this car (barely runs at the stock spec, 10 deg, but has no sign of pinging even at 15-16 deg), and all the other variables have been gradually eliminated (new timing set, harmonic balancer, different timing light). We're hoping that this will finally fix some of the lack of power this car has had.

 

We could not believe it when the old balancer was dead on with the new one. Granted the rubber ring was cracking, but sheesh! My car is never the obvious...