Flywheel/Starter noise

[renegade_jlp]

Okay, so I was starting to get a really loud, high-pitched, noise from my engine. I sent the car to my mechanic and he replaced the starter saying it was hitting the flywheel. It's been about a week and the sound has started up again, but it's not as loud and not all the time. The noise only starts up when it's in gear (1st, 2nd, 3rd or Reverse) and even then only sometimes. When I put it in neutral, no sound, everything runs fine. BTW, I have a stock auto tranny. Could someone please help, I've no idea how to approach this myself.

 

[cruzer99]

So what engine, tranny, what year, etc..........

 

[renegade_jlp]

Yeah, I forgot about all that... it's a 76 with the stock 350, aftermarket pipes, and like I said before it's got the 3 speed auto from that year

 

[hotrodd]

Just a thought.How is your oil pressure when it make's the noise?I had a 350 with a bad crank thrust bearing that did that but it was a manual trans.The pressure would drop to almost zero at idle.

 

[vette-dude]

Renegade
Does the noise only happen when you take off from a stop or is it all the time while you are driving? Have you been hot rodding the car from standing starts recently? (hey I'm not a cop so tell the truth!!) I suspect that you may have a cracked flexplate or if the sound is more of a whirring screeching noise you may have busted a sprag bushing in trans. I hope I am wrong on both these but it is hard to diagnosis without hearing the noise. The other thing it might be is the starter (rebuilt right?) bendix is not retracting or it is not shimmed correctly.

Now about that oil pressure thing on hotrod's vette, was it the thrust bearing on the crankshaft that went south. Manual trans cars have a tendency to shuck this out because of the hammer effect of dropping the clutch to do a burn out. It drives the crank forward and wears out this thrust bearing. Auto cars have the convertor to take up the hit and are much easier on the rear main thrust bearing. Just curious about the brg thing. Shuck a few in the old days, have an automatic now.

 

[vette-dude]

Hotrod,
just noticed you are from Belle Plaine, KS. I used to live in Lyons, went to college in Wichita and from Emporia originally. Next time we are back that way we'll holler at ya.

 

[renegade_jlp]

Well it's gone, I started the car up today and no noise whatsoever. Just to let you know, it was only when I was stopped and in gear (like at a light). It would also sometimes start up when going very slow (under 15 mph, like that ever happened!). It's a rebuilt starter so I think that might be the problem. It'd be nice to know what happened though, I know the problem's going to start up again as soon as I forget about it.

 

[cruzer99]

It could have been a weak or bad bendix spring that allowed the starter gear to slide into and bounce off of the flywheel.

 

[JohnZ]

Do you still have the brace from the forward end of the starter motor case to the block? Many "mechanics" don't bother to put the brace back on when they change a starter, and without the brace in place, there's a terrific overhung load on the Bendix and the pinion that closes up their clearance to the ring gear. Starters last a LOT longer and work quieter with the brace installed.