Hey guys! Last time I posted I was having issues with the engine. Lucky enough for me, when I fix one thing, something else gets broken. After I timed my distributor following engine assembly, everything was great then the starter started grinding and soon enough wouldn't catch the flywheel.

To be safe, I just bought a new starter that was the same model from autozone. The model was a P6449s. When I tried to put on the new starter I realized that one of the mounting bolts broke and had to extract it. Well I put on the new starter then later the grinding came back within days and the other bolt broke. Took it to a mechanic and we just started fresh with an all new starter of the same model and new grade 8 bolts and everything was fine for 3 cranks then it started grinding and wouldn't catch the flywheel at all.

I'm thinking that the starter is just not moving the pinyon gear over far enough to mesh with the flywheel. But if that was the case, then why would it work for 2 days then not start at all? Does it need to be shimmed? Or do I need a completely different model starter?

The flywheel has been examined and is fine. And the the engine is a 350 from a 96 gmc z71.

 

It sounds as if it needs to be shimmed.

 

I really hope so. It just doesn't make sense how on both brand new starters it would work flawlessly for two days then just decide to not mesh with the flywheel at all....

 

because after two days you wiped the teeth off the starter gear and they won't mesh anymore.

you want at least .035 of clearance between the starter gear and the flywheel when they engage.

If the clearance is too tight, it will grind right away (as soon as you crank it)
Shim both bolts to increase the clearance.


IF the clearance is too loose it may work for awhile, but then the starter gear will wear out and not engage the flywheel.
Shim the outboard bolt only. (furthest from the flywheel) to decrease the clearance.

You can use a standard paper clip as a gage.

You also want to make sure you have no more than 1/16 gap
between face of the flywheel and face the starter gear. if you have to much gap the starter gear will not engage the flywheel with enough material and the teeth will round off.

Make sure the flywheel is plumb, check this clearance at three locations on the flywheel. if the gap changes you have loose or warped flywheel.

You have to ask yourself why the original starter failed? bolts don't shear off without a reason.

Be sure to use the correct starter bolts, they are knurled to center & hold the starter base correctly to the starter pad in the block. if they are too long a few washers can be added under the head of the bolt. don't substitute the bolts.. grade 8 means nothing if the bolts are not knurled... You can buy the correct starter bolts from NAPA, Summit etc..

most case you don't need shims.. but not every engine block and starter mounting pad was machined the same...

 

Thank You so much! I'm taking it would probably be best to just get a new starter and give it another try with the shims. I do have some shims but the only ones that AutoZone had were full shims. How would I shim the outboard with a full shim? Cut it in half?

 

Sounds like a bad flywheel.

 

Correct, cut the shims in half and use it on the outboard bolt... if you need to decrease the gear to flywheel mesh clearance.

but also check the flywheel for run-out, as I described.