Starter spins, won't engage flywheel

Jon B

I presented this problem late last year, and several of you had some helpful suggestions http://openforum.hetclub.org/discussion/167909/technical-advice-needed-malfunctioning-starter-drive/p1

However, I still have the problem and wondered if anyone had any new insights!

Basically: the starter on my Terraplane usually engages when I push the button, but one time in three, it does not.  Then it will just spin and no matter how many times I hit the button it just spins. When it spins I hear it vibrating like something's out of round.

So, I get out of the car and rotate the Bendix a couple of clicks.  Then when I hit the starter again, it will engage okay. Then next time around, it may or may not free-spin again.

And so it goes.

The Bendix was newly rebuilt last year, and installed by an auto electric shop.  (This happened because -- prior to that -- the starter WOULD engage, then jammed the flywheel.  I had to unbolt and remove the starter to un-jamb it.  So that's why I had the Bendix replaced.  I also dressed down two or three teeth on the flywheel which were slightly damaged.  After all of this, the starter stopped jamming, but it started free-spinning!

I took it to another specialist who carefully inspected the starter and said nothing was wrong with it.  But I still have the free-spinning problem.

Is it possible that the shaft is bent, and that this makes it hard for the Bendix to slide forward into the flywheel? 

I have cleaned all the grease off the shaft, I have greased the shaft, I have tried this and that....to no avail.

I'm going to keep my eyes peeled for another starter, even a used one, just to see if that might help the problem!

SuperDave

Try cleaning the drive with BrakeKleen, then oil with a very light oil..maybe kerosene or diesel fuel. Grease will slow down the mechanism especially in cold weather. It does get cold in Virginia?

Frankvintagefullflowcom

If I follow the chronology of events correctly, the starter drive would always engage before the jamming event and now it occasionally fails to slide ahead on the shaft. These, with the accompanying vibration while running "non-load' implies that the shaft is, indeed, bent. If bent that far, it should be fairly obvious but you may need to take it out (you do know how to do that by now, right?) and throw a dial indicator at it and turn by hand to see for sure.

My two bits worth.

Frank

Jon B

Thanks for your thoughts. 

Essentially, I've only started the car in warm (60's to 80's) degree weather so I would rule out "heavy grease".  I had been told that there should be NO oil or grease on the shaft itself, so had cleaned that off.  Later, I heard that one SHOULD have lubricant on the shaft so I first tried graphite, then, later, WD-40.  Nothing I did, helped the situation.

Frank, even if I put a dial indicator on the shaft I'm not sure what the "acceptable" out-of round would be. It does seem strange that I get this significant vibration when it free-spins, though.   I'm going to try to find a used starter just to see if it improves the situation even slightly (if not, maybe the problem lies elsewhere, like with chipped teeth on the flywheel maybe).

SuperDave

I think Frank is on to something with the vibration. Slightly bent shaft and could also be a bad drive end bushing. The fact that it has jammed in the past could be when it got bent.

Geoff

The vibration is due to the   bendix studs, the whole assembly is inherently unbalanced, and when free spinning will vibrate.  The worm should be absolutely dry.

Frankvintagefullflowcom

True, they aren't  very precise when it comes to balance. It's a bit too crude of a device to get picky and it only runs no-load if it fails to engage so you wouldn't notice it when operating normally.

Re: runout. I'd guess <.005 and even that much would suggest that something bent it. The drive-end bushing should be no more than .005 clearance either (and that's too much for me to accept). If you can move the shaft radially any noticeable amount, it's suspect. I failed to mention that because you had mentioned that it had been inspected by an "expert" and didn't want to insult him/her by suggesting that they'd missed something as obvious as shaft bend. Now I don't care. Heck, send it to me. I'll check it, straighten if necessary and keep it......err, I mean, send it back.

I just installed a "rebuilt" starter on a member's 212 that had a worn out D/E bushing. I never trust anything that comes billed as rebuilt so I caught it before it went in.

F

Geoff

"Rebuilt" = looked at  and appears O.K.!  Sprayed with silver paint. 

Uncle Josh

Maybe it doesn't believe in getting engaged Jon