Distributor Timing

[Duke W.]

Re: Distributor Timing

This is the case with ALL C2 small blocks and many other Corvette engines of the era.

Duke

[Joe C.]

Re: Distributor Timing

I did not disconnect the vacuum hose and plug with success. . With vacuum on the engine ran smooth at idle. Just no power when driving. At first I tried to disconnect vacuum line and block.... engine hardly idles at low speed.
Reading between the lines the vacuum line must be off and blocked to set timing. Since the engine hardly runs doing that .... then do I need to find TDC and start over?

Your engine should be timed with at least 8 degrees spark advance at a 500 RPM idle, and you should temporarily increase the curb idle speed screw to keep it running when you disconnect and plug the manifold vacuum source to the advance can.

If you don't want to do any of that, then since the vacuum advance should be pulling an additional 17 degrees at 500 RPM idle, then adding 8 degrees initial to this gives you a minimum of 25 degrees, at 500 RPM, with the vac advance connected. If you don't have your harmonic balancer degreed, and you don't have a dial-back timing light, then you're flying blind checking it this way..................unless you somehow marked the balancer at the 25 degree point before you started this project.

[Tom I.]

Re: Distributor Timing

After re-assembling the distributor on my 62, I could not get the proper timing position. I removed the distributor and counted the teeth in the gear. Turns out the gear has 21 teeth and if the gear is put on 180 degrees out the timing is off enough that the vacuum advance can will not allow proper timing regardless of tooth selected when inserting the distributor. When I rotated the gear 180, proper timing was possible. I believe the reference to the dimple on the gear was for proper indexing.
Tom I.

[John H.]

Re: Distributor Timing

I removed the distributor and counted the teeth in the gear. Turns out the gear has 21 teeth

Tom -

I think you'll find that the distributor drive gear (and the camshaft gear) have 13 teeth.