starter engages about 20% of the time

[redstone65]

20% may be generous. I had it worked worked on because about 80% of the time it won't engage. They said they couldn't find anything wrong with it, but they did adjust the washers to see if that would help. After putting it back in, it worked the first 4 or 5 cranks no problem. Then it stopped engaging again.

When I say that it "doesn't engage" what I mean is that you can hear it clang off of the flex plate like the alignment between the two isn't right. But, if that's the case, I don't know why it would ever engage at all. If I crank it 10 times it may work 2 out of those 10. The rest of the time you just hear it hit.

Sometimes it just won't work no matter what, and I have to get out and rotate the crank by hand with a breaker bar. After that it'll work about 50% of the time.

What's odd is that when it does actually engage, it sounds perfect. No grinding or evil noises. Sounds just like it's supposed to.

My only guess is that the starter nose isn't penetrating deep enough into the bellhousing, so that, when it does engage, it's barely catching on the teeth of the flex plate. The rest of the time it's just grazing the edge of the flex plate. Does that sound like a reasonable hypothesis?

[sargentrs]

Have you inspected the teeth on the flywheel? I had one on a '79 Mustang that a few teeth were chipped on the starter side. When that spot came around it would not engage. I could roll the car forward a little and pop the clutch and the engine would rotate enough to skip past those few bad teeth. Then she'd fire right up.

[cep62]

On a 90 degree V8 the engine usually will stop in 4 places .
if you look at a used ring gear you'll see the wear pattern.
so you'll have a 25% chance of it stopping on the bad teeth, if you crank the engine a little you get fresh teeth.
The odds increase in bad weather and when you're running late.

[redstone65]

I took pics up in the inspection area today but it’s hard to see. I’m going to have my son rotate the engine by hand and watch as all the teeth come around. Hope it’s not flex plate damage. Don’t want to drop that tranny again.

[redstone65]

Ok I inspected the flex plate and there are some ratty looking sections in it. It’s a ‘74 360 engine. I have a spare flex plate in great condition from what I believe is a ‘70-‘72 era 360. Did the ring gear tooth count change from 70-74?

I’ve seen mention of a 184 tooth and a 140 tooth.

[sargentrs]

Rockauto has it listed as 184 tooth from 68-76.

[Gray035]

I have gone through so many starters on my truck. What I've found is that many starters are cheap rebuilds that are not strong enough to engage the flywheel because they have worn internals. I suggest you go buy a new (non-rebuilt) starter. You will marvel at the difference.