I have an 89 sbc350. I replaced the stater and shimmed it with the provided shim...umm...stick, rod...thing.
I gave it a test bump and it sounded great. A little wile later I decided it was time for a burger from down the street. I hop in, start her up, let it get to temp and take off. After I eat, I step out to start her up and all you can her it the teeth on the fly-wheel screaming in pain. Just ''Chunk, Chunk, Ching''....
It seemed like it was not turning fast at all. I get a buddy to give me a tow home with his tow strap.
I check the shim and its right on. The fly wheel has no missing or deformed teeth..... please help...

 

did you try it without any shims to start with? on any third gen engine v8 ive personally ever done a starter on i never needed a single shim. thats not to say it doesnt happen of course, but if you havent tried, take the shim out and before you go out to get your burger test it a few times to be sure its all good. remember we as chevy owners have a responsibility here to never be the towed, but be the one towing. in fact whenever i towed my friends imports or non gm's with my truck, i always snap a photo with my phone and post it on facebook. haha. that way when they bring up how their import never breaks down or their jeep is the best blah blah..well you get the picture.

 

Very good point sir. Thank you. I'll give it a try with out the shim after it get a little more light out. I've got a diy paint booth setup in both bays of my garage right now.
If you makes you feel any better, it was a 81 chevy step side that towed me.

 

Are you sure you were hearing a gear mesh noise, and not the starter solenoid trying to engage the bendix gear? Our cars tend to overheat the starters if you don't have a heat shield in place (just like they came from the factory), especially if you have headers. Besides, I don't see how being warmed up is going to change the gear mesh, unless the starter is loose. Since the mesh still checks out, does the starter work ok now? That would be another tell-tale sign that you're having heat soak issues.

 

I was thinking heat soak myself because the theeth aren't going to grow more than a few thou when the heat up. The rod they give you is like .80" or something. i've never used one BTW, its too hard. I listen for screeches.

 

I use a 1/8" allen wrench, as the bent end makes it easy to get between the teeth on flywheel and starter. I also pull the solenoid while checking, and once I get the clearance right I pull the starter and reassemble it.
But I've rarely shimmed a starter on any of my own cars, it's always been for a friend's car.

 

I did not have much time to mess with it today. I have a few rolls of heat wrap from some headers on a harley I just sold. Would that work?

 

But you didn't say if the engine started like normal after it cooled off. If so, you could do a scientific test. Go for another burger run, but take one of those flexible ice packs with you (frozen of course). When you get there, lay the pack on the starter solenoid. Then if it starts with no problem when you get back out, it's a heat problem. Instead of taking a chance of getting stranded (in the off chance that it isn't a heat issue), you could drive around the block for a while to heat it up, and pretend your house is a burger joint. Oh yeah, and what time should we be over? I like mine cooked medium.

 

Medium here too!

 

I wouldn't use header wrap on a starter. If it gets dmp it holds moisture, and that's not good around a starter. I'd either buy a heat shield, or build one from some lightweight aluminum. They're cheap either way.
$16- http://www.summitracing.com/parts/OER-361443/