I have a starter issue with a 79. I replace the original L48 engine with a new GM SP383 crate engine about a year ago.
The engine came with a JEGS Hitachi style mini starter. Everything has been fine with the engine, but I began to have some issues with the starter a few weeks ago. Every 8 - 10 times I would try to start the car I would get a high pitched screeching sound and the engine wouldnt turn over. I would shut the ignition off and try to start again and it started right up. I took the starter out and had it tested and about every 8 -10 times it was powered the pinion gear would stick. So I assumed that the sticking pinion gear was the problem. I was warned that those starters are not high quality. So I bought a new PowerMaster 9100 starter. I installed it and when starting it up I could hear it spinning but the engine wasnt turning over. It appears to not be engaging the flywheel. I checked for power and I have adequate power where I'm supposed to and the installation appears correct. I took it out and jumped the ignition wire post to the battery post and verified that the pinion gear is extending and spinning. I also verified that all dimensions are exactly the same as the JEGS starter that I took out. I'm about to put the old starter back in so at least I can get the car on the road but I'm stumped as to what the issue is. Any thoughts are appreciated.

Thanks in advance.

 

You went over the instructions concerning pinion engagement and pinion depth?
https://static.summitracing.com/glob...s/pwm-9100.pdf

 

Thanks Mel.
I did review that information. But what baffles me is that certain measurements are supposed to be taken on the pinion gear relative to the flywheel while the starter is mounter to the engine block. For example: "Insert a wire gauge to check for proper backlash between the ring gear and starter pinion". Not sure how this is possible with the starter mounted. As far as I can see it's impossible to get a wire gauge in there. I spoke to PowerMaster tech support and they gave me a measurement from the center of the bolt holes to the face of the flywheel. This I can measure with the starter out and I plan to take this measurement in a little while. However if the distance is too large I'm not sure what options I have other than checking if there is a shim inside the starter body and removing it. But I'm skeptical that 6/100 of an inch will allow the pinion gear to engage properly.
Am I thinking about this correctly?

Thanks again for the response.

 

Chevy has two starters one for a 153 tooth flywheel and another for the 168 tooth. Do you know what flywheel you have and did you replace it with the correct Powermaster starter?

Edit: It appears the powermaster 9100 works for both and has two sets of bolt holes. Did you use the right ones when installing it? You may just need to use the other set of bolt holes to get the pinion to engage the flywheel.

 

Thanks for the response.
You're correct that the 9100 works for both 153 and 168 tooth flywheels.
I did check the alternate bolt holes and if I use them it will move the pinion gear further away from the flywheel.

 

Replace 79's starter with a PMGR starter like what has been OE on GM V8 / V6 for over 20 years. Under $70 delivered.
Powerful, light, small ... Reliable.

if yours has the smaller 153 T flywheel (and it sounds as though it is) then use this "straight" pattern
https://www.dbelectrical.com/product...t-sdr0059.html

if it's the larger 168 T flywheel then use this "staggered" pattern
https://www.dbelectrical.com/product...sdr0019-l.html

 

Update....I put the original starter back in and the same exact thing happened as with the new starter....it sounds like its spinning but not engaging the flywheel.heel
Previously the original starter turned the engine over most of the time, but occasionally I would get a high pitched screeching noise.
I spoke to a mechanic friend of mine and he believes its the flywheel (he didnt see the car as I cant move it right now). I'm skeptical of flywheel because all of the teeth that I can access seem fine, so that would tell me I should get at least partial engagement with the flywheel.

He told me to turn the engine with a socket on the crankshaft pulley and feels pretty strongly that it'll start up. If that works, at least I'll be able to drive it to his place to take a better look at it.
Thanks to all for your input and I'll post again with an update.