Iv never replaced a starter before, so i don't know anything about using shims or anything like that. but i replaced a starter on my friends camaro. and now it grinds whenever we try to start it. I now know i need shims for it .. but how do i know how many or anything like that. Cause we HAVE to get this done today (school tomorrow) and i haven't a clue what to do, besides trial and error.. any help?

 

as a rule if it had shims originally you just put the old shim back in with the new starter. i've never saw more than one shim on a SBC so it'd be safe i think to just add one shim.

 

You'll be adding a shim(probably and old washer) between the starter and where it bolts to the car. You just want to chenge the angle slightly so it will engage the teeth correctly.

 

The shims are used on a sbc because mounting pad tolerances vary from block to block.The aluminium nose house dimensions vary also.All this can move the starter away from the flexplate by varying distances.Regardless of whether the old starter had shims or not you must inspect the clearance of the new unit as it may or may not need shimming.Look for the wear pattern on the flexplate.If the teeth are only just touching the flexplate you have too much clearance.If the teeth are are meshing too deep into the flexplate you don't have enough clearance.
To increase clearance you must use a shim across BOTH mounting holes (This will take starter away from the flexplate).A .015" shim will increase clearance by .0075",use no more than 4 shims.
To decrease clearance you must use 1/2 a shim on the outer mounting bolt,the one furthest away from the flexplate (this will move the the starter closer to the flexplate.A .015" shim will decrease clearance by .010".
To check clearance,centre a tooth of the starter with the flexplate (Insert a screwdriver in the small hole in the bottom of starter drive end hosing.Move starter drive assembly out towards flexplate so that teeth mesh).The correct clearance should be between .025" and .060".(check this at 3 locations at 120 degrees apart to ensure correct clearance).A convenient plug gauge is a common paper clip which is typically .035".
Hope this helps.

 

What kind of transmission is your friend running. When I put my engine in, I replaced my starter with a Powermaster mini-starter, and it was said that if running a manual transmission to shim the starter 1/8". I did this and have had no problems at all.

 

so.. using say.. 5 shims to get about 1/4" of more clearence is a bad thing???


With no shims all it did was grind.
With a .06" shim, it grinded alot and turned over.
and it wasn't until we had two .06" shims, two .04" shims, and a .02" shim that we felt good starting it, even though it was still grinding some..