HELP!! Starter problems

[emanuelK]

I realized short after the purchase of my car that the starter sometimes failed to grip into the flywheel starter ring gear. A terrible sound let everybody, up to a 1/2 mile distance from the car, know that I had a problem.

After a week or two the number of fails increase until it became static. I bought a new kit with a starter gear and also checked the flywheel. It was not perfect but I could not observe any major problems. I was recommended to shim the starter and when I installed the remanufactured starter I shimmed it on the outer bolt with approx 0,8mm ("0,03")??. The first start was extremly smooth and I thought the problem was gone. But....

Today I 'm facing the same dilemma again. What is my problem? Shall I shim even more? Can I measure how much I need to shim? Do I have wrong starter?

I dont want to replace the flywheel now at this time a year. I'm going to remanufacture my TH350 transmission during the winter and intend to replace the flywheel at that time.
Please advice. Thanks /Emanuel

[camaromikey]

does it do it all the time or just every once and a while

[hotrod68]

I've been through this....doggone it, and it ain't pretty. It sounds like you have worn and rounded teeth on your flexplate somewhere in the rotation, and the only way to really fix it is to replace the flexplate and starter Bendix. Period. Chuckle...the damn thing will ALWAYS come to rest at the worn teeth when you shut the engine off! Shimming doesn't work because it moves the starter Bendix AWAY from the flexplate and just makes it worse. Continued cranking will only chew the flexplate and Bendix up that much more until it strands you or makes you turn the engine by hand until the Bendix can get a grip and turn the engine. If you do replace the flexplate and starter, take the solenoid off the starter so you can manually move the Bendix into the flywheel teeth and measure the clearance. Ideal Bendix-to-teeth clearance is about the thickness of a paper clip between the Bendix tooth high and the low between the flexplate teeth. Good luck!

[emanuelK]

This is a correct description of the problem. I'm more or less aware of it because when everything i OK and the starter runs on the flexplate I can hear the sound slightly change once per revolution. There seem to be a couple of cogs that are more worn than the others.

I'm just not in the mood right now to do the job and separate the transmission from the engine. But it now seems it's not up to me if I want the car up and running this summer. I will buy a new flexplate. Any good supplyer on this??

Question: If I place the shim on the outer bolt the closer the gears will be?? See my attachment.

[Wallace]

I had a similar problem on the flexplate behind my 396.  I had several gear teeth that were dinged up a little bit, and the bendix would find them often with embarrassing grinding.  I removed the dust shield underneath and rotated the flexplate (engine) and when I found a chewed up tooth I dressed it up with a flat file.  If your damage is not too severe this might work.  My bendix had no damage to the gear.

Wallace

[JohnZ]

Do you have the brace installed at the forward end of the starter housing that bolts to the block? This part is frequently left off when starters are replaced, and without it, the starter nose deflects or breaks, and/or the starter pinion teeth no longer have clearance to the flywheel teeth, making a LOT of noise and tearing up the starter pinion shaft bushing in the nose casting.

[emanuelK]

Yes, the brace is there. I replaced the previous gear with a new one a month ago and I was careful bring that on. Today I removed the transmission case and checked the whole flexplate starter ring gear. It has more or less damage on every theet. So the decission is taken now to replace it. I ordered a new one today and together with a new gear on the starter I have something that probably will last for a long time.

Thanks /Emanuel

[emanuelK]

I did some research and made a dummy where I installed the starter gear. I bolted it on the engine an checked the gear clearance. I now have to agree to the statement that any shim inserted between the starter and engine increases the distance between the gears and don't result in any improvement.

[emanuelK]

I replaced the flex plate this weekend and now the starter works just great. I'm not sure why this problem occured but I have a theory, the flexplate was probably installed the opposite way. The position of the gear on the flex plate is not symetrical and the overlap between the starter and the flexplate seemed to be only approx. 60%. If the flexplate was installed the opposite way (I think the right way) then the overlap would be total. Theoretical is this a possible reason but I don't know if it's possible in reality. What do you say guys??

[rich69rs]

If the flexplate were on backward, I don't see how you would ever be able to bolt it up to the torque converter.  At the flexplate to torque converter bolt locations, the side of the flexplate that goes toward the torque converter is diferent then the side of the flexplate that faces the engine.  Attached pic shows this but not very well.

[rich69rs]

I now have to agree to the statement that any shim inserted between the starter and engine increases the distance between the gears and don't result in any improvement.

Generally shimming a starter is only required if there has been any decking on either the starter mount on the block or on the mounting flange on the starter itself. 

Any decking on either of these two surfaces will cause the bendix gear to engage more deeply in the flywheel gear teeth with reduced clearance and backlash, or worst case not engage due to physical interference.  Installing the correct thickness of shims re-establishes the proper clearances and depth of tooth engagement that was lost during the decking operation.

As an example, the starter currently installed on my '69 RS has had its mounting flange decked in order to square it back up.  When the auto electric shop performed the work, they made note of how much the mount was decked in order to bring it back to square.  When they returned the starter, they included an equal thickness of shims to the amount of metal removed during the decking operation.  When I installed this starter during my engine rebuild a couple of years ago, the shims were alsso installed - thus maintaining the origiinal clearances and depth of tooth engagement.

[emanuelK]

HELP again...
I'm close to give up this problem. I thought it should be a piece of cake to solve but NO....
I replaced the flexplate (new one) and the starter gear (also new). The new installation sound good for a month but now it seems that the problem's back. Today I heard the hated sound again and now I'm really out of ideas what to do.

Shall I replace the whole starter instead? It looks new (I think the previous owner changed it to solve same problem - but not sure). Are there any measures to check to be sure I have the correct parts? I assume if the starter is possible to bolt on the engine it should be the correct one.

Any help is very much appriciated. Thanks /Emanuel

[emanuelK]

In order to save new information for future use I add this post.

With no ideas of the reason to my problem I decided to buy a new starter. In the box was a shimming instruction attached stated that a Chevy starter must be shimmed to avoid this kind of trouble. Never heard of this as a demand before but it seems logical and may explain my problems. On page 2 last image showing the wear pattern compared to my gear it seems that I had to little clearance.

Hopefully this may be useful to someone.
Thanks

[bc69]

Have somewhat similar problem that started after a starter bendix change. At times, numerous times the bendix will not go into the flywheel or mesh when attempting to start. You have to turn the key to start a few times, during which you hear the bendix slap the flexplate but not engage because it didn't mesh.
I have shimmed, shimmed, shimmed until..... I have had the bendix changed again, used all parts of another starter, but bendix.
Checked the flywheel with all seeming to be OK?? Missing something. Any thoughts?
Note: I attempted to knive the edge of the bendix to remove any flat spots on the outer edge and it seemed to help some. But still not solving problem.

[Stingr69]

Are your 2 starter bolts original GM?  They need to be.  Is the brace in place?

How much gear clearance do you have?