Starter Shimming

[Bandit130]

Want to know information about shimming a starter. How I know I need to and how much shims to use.

72 C10 350/350 auto.

Thanks.

[Molberg]

I would start with no shims. Bolt starter in place. Remove flexplate cover. Use a small screwdriver and mesh starter drive into ring gear. Should be able to just fit a paper clip in between the tooth of the starter drive, and the valley of the ring gear when meshed. If not, add a shim and try again.

[67swb72klb]

here is a video that might help

https://www.youtube.com/watch?v=IVHXmWMKzq4

[Fitz]

Originally Posted by Bandit130

Want to know information about shimming a starter. How I know I need to and how much shims to use.

72 C10 350/350 auto.

Thanks.

There's a lot of folklore and BS out there about starters and how to shim them. Remove the dust shield and starter wiring, then remove the starter. Once that is done, the easiest way to determine IF your starter needs any shims and most don't, is remove the solenoid so the starter pinion will stay forward in the start position, bolt in the starter without torqueing the bolts and measure the pinion to ring gear clearance with an ordinary wire paperclip.

Since the solenoid is not holding the pinion retracted into the nosepiece, this is easy. Move the pinion in and out to be sure it's free. If not, add a 0.020 shim and measure again. When the clearance is correct, then remove the starter, re-install the solenoid and permanently install the starter. You may run into a situation where the solenoid just 'clicks' and the starter does not turn over. If that happens you have a bit more work to do. The pinion on most new gear reduction starters does not have a sufficient chamfer on the engagement side of the teeth to force the starter pinion to turn slightly to allow the pinion to engage with a straight cut ring gear. The pinion just bounces off the ring gear making that all too common disheartening loud click that lets you know your truck isn't going to start. Get a Dremel tool and increase the size of the chamfer on the front of the pinion teeth to about 2/3 of the way across the face of the teeth using a 45 degree elevation and a 45 degree rotation of the tool. Stay off the length of the teeth, just work on the face of the gear but be careful not to scar the pinion shaft. Re-install the starter and I bet it cranks!