Starter problem

I have a 80-85 chevy 350 motor in a custom car I built. Everytime I start the motor about the 4th time or less the starter pinion will fall out and then just grind against the flywheel. Basically the pinion eventually comes of its alignment and won't mate with the flywheel. What do I do to correct this problem?

I have a 80-85 chevy 350 motor in a custom car I built. Everytime I start the motor about the 4th time or less the starter pinion will fall out and then just grind against the flywheel. Basically the pinion eventually comes of its alignment and won't mate with the flywheel. What do I do to correct this problem?

Check flywheel for bad teeth.
If good rebuild or replace starter and check starter pinion spacing.

Thanks for the reply MT-2500. My flywheel and starter are both new and the teeth have never been worn. I think its the starter spacing...how do I check the starter pinion spacing? I notice when I pull the pinion out so it fits between the flywheel teeth. It fits between the teeth of the flywheel but it stays stuck in-between the teeth of the flywheel, the pinion dosent slip back out and no matter how much I adjust my starter motor braket I still get the same problem. What is that about?

Thanks for the reply MT-2500. My flywheel and starter are both new and the teeth have never been worn. I think its the starter spacing...how do I check the starter pinion spacing? I notice when I pull the pinion out so it fits between the flywheel teeth. It fits between the teeth of the flywheel but it stays stuck in-between the teeth of the flywheel, the pinion dosent slip back out and no matter how much I adjust my starter motor braket I still get the same problem. What is that about?

Have you tryed adding shims?

I dimly recall that the spacing between the 'peak' of a tooth on the starter Bendix and the bottom of the inter-tooth 'valley' on the starter ring of the flywheel should be about .040". That is, if you added a pair of .020" shims, it might be just right. Still plenty of 'engagement', but no binding will happen. And I would hope any auto parts place would know what you meant when you asked for 'Chevy starter shims'. They may come in a bubble pack in that 'HELP" line of goodies.
I would advise using a torque wrench to tighten the two bolts supporting the starter too.