Stripped Distributor Gear - Need a Machine Shop

[Lowell W]

I set up an extra MSD distributor with a steel gear for my car as a backup. Before I removed the original distributor, I set up a dial indicator and measured the distributor shaft play in and out. Can't remember the numbers now, but it was about half the amount I measured with the distributor out of the car. So far, so good. I pressed the new gear to the dimension indicated by MSD, then measured the play in the new distributor, installed it and measured again. Again, I had roughly half the play in the installed distributor.

As has been noted elsewhere, the forces on the gears act to draw the distributor shaft down into the block. The bottom of the cam gear acts as a thrust face for this "pulling down" force.

Can't recall...maybe I posted this somewhere else already... Well...hope it helps...

Lowell

[jetenginedoctor]

The cam does pull the distributor gear down toward the oil pump, but the thrust load created by the interaction with the cam is not enough to cause the damage done to the gear I saw from Steve's car. What had to cause that was the distributor shaft having signifigant axial load stress grinding the distributor gear against the landing inside the block, or otherwise clearances itself. Unfortunately for Steve, it appears that the heat generated between the bottom of the distributor gear and the gear landing surface within the block was enough to at least momentarily seize the gear and shred teeth off of the softer distributor gear. The only way this can happen is if the distributor drive gear was installed too "low" on the distributor drive shaft. Don't make the mistake of assuming that just because it comes from MSD that way, that it's correct.

YMMV

BK