starter shimming

[black dawg]

Picked up a 95 k2500 that the flexplate ring gear was destroyed......never got to hear it run. put a flex plate in it and a new starter (newer style small gm gear reduction).
Starter sounds bad, so try another one that I know sounded good off of one I parted out....same sound. Sounds kinda scratchy like one sounds with loose bolts.

Talked to the previous owner, and he had problems with starters, and atleast one broken bolt, so I dont think this has anything to do with this flexplate.

Started playing with shims, adding to the outside bolt to get the starter closer to the ring gear. With about .200 worth of shim on the outside bolt only, the starter sounds pretty good, not quite normal, but maybe ok?

I really dont like having it shimmed that way, do I have any other options? My next thought is machining the starter. Engine is a few year old 5.7 gm crate, bolt holes look good and starter mounting pad on the block looks good.

 

[Blue85]

I remember something about a round feeler gauge you put between the flex and starter. I thought shims were only increase the clearance.

 

[black dawg]

I remember something about a round feeler gauge you put between the flex and starter. I thought shims were only increase the clearance.

I have not actually measured the clearance, the lower bellhousing cover wont come off of this thing with the exhaust there. I never knew of shimming the outside bolt only, to make it closer either.......I guess it wasnt that uncommon with the older gm stuff...according to the local old guys. I am just uncomfortable with the amount of shim in there......added another thick one last night and now it sounds almost perfect.

 

[TJ1978]

Flywheel and starter bendex clearance is measured with a paper clip for proper engagement

 

[TJ1978]

..

 

[Wes Harden]

Do you have the correct starter for the number of teeth on the flywheel? I know there are 2 different 168 and 153.

 

[rampage]

Flywheel and starter bendex clearance is measured with a paper clip for proper engagement

View attachment 385908

View attachment 385909

Paper clips are of different diameters depending on their size so this is an inaccurate way to measure.

 

[TJ1978]

Paper clips are of different diameters depending on their size so this is an inaccurate way to measure.

1/8 .035 inch paper clip is whats used or standard size.
It's one way...

 

[Wes Harden]

Not to be nasty but 1/8" is .125"
1/16" is .0625 1/32 is .031
So a 32nd of an inch is much closer to the .035.

 

[TJ1978]

All I know is I have done the paper clip option and it has worked. I don't and haven't claimed it is the end all be all. Just an option to get the bendix engagement to the flywheel correct.

 

[Wes Harden]

Yes paper clip works well, I have used one many times.

 

[500$k5]

Over the years, i have run into 2 or 3 sbc, that the starter was too far from the flywheel. Multiple different flex plates/starters didnt fix the problem. I have no good answers for you. The difference, between the 153, and 168 tooth flywheels is too much to shim it, so you must have the 168. This probably causes more questions than answers. Sorry

 

[black dawg]

Over the years, i have run into 2 or 3 sbc, that the starter was too far from the flywheel. Multiple different flex plates/starters didnt fix the problem. I have no good answers for you. The difference, between the 153, and 168 tooth flywheels is too much to shim it, so you must have the 168. This probably causes more questions than answers. Sorry

I have several of these starters laying around, so I think I am going to machine one down and see If I can make that work.

I could try another flywheel, but the one I removed looked to be the original 95, that survived the original engine and I am thinking the problem is with this block. The starter does sound good now, doesnt even catch my attention when I start it, but just dont like how it feels tightening down the starter with it shimmed that way, and concerned about maybe?? breaking bolts.

 

[Blue85]

Maybe if you have a nose machined down to fit, it can be swapped onto other starters in the future if a swap is needed.

 

[black dawg]

Maybe if you have a nose machined down to fit, it can be swapped onto other starters in the future if a swap is needed.

My thought is after I get the nose cone machined......and everything works correctly, I will have a second also machined down (so I have a spare) and when the first one has problems I will just take it to a rebuilder, and have a spare on in the mean time
I am going to pull that lower cover off and measure the engagement before I do anything else, When I had the starter off the last time I was shimming it, looking at the shiny spots to see engagement on the ring gear, it almost looked like the engagement front to back was also really poor....like less than 1/4 of the width of the gear tooth.

 

[imiceman44]

I have not actually measured the clearance, the lower bellhousing cover wont come off of this thing with the exhaust there. I never knew of shimming the outside bolt only, to make it closer either.......I guess it wasnt that uncommon with the older gm stuff...according to the local old guys. I am just uncomfortable with the amount of shim in there......added another thick one last night and now it sounds almost perfect.

That's how we always did it on our old mid 70's Chevy. We shimmed where we needed to get the smooth start.
I have not needed to do this in years though.