Starter problem 1981 Chevy 1/2 ton?

Question

Vehicle: 1981 Chevy 1/2 ton (Scottsdale)
Specs: 305ci (according to VIN);

At about the end of my wits on this one...

Problem: Starter sounds like it's trying to tear teeth off the flywheel.

Attempts to resolve:
Changed starter. worked for about a week, then started happening again.
Shimmed starter. worked about a week, problem again.
Got new bolts. good for a week, problem again.
Was able to realign and each time it happened and then problem again.
Got bigger bolts, this time size and installation by my mechanic.
Worked for about a week and today same thing.

Possible pattern: I've noticed that the problem doesn't happen unless the truck has been stopped for only 5 minutes and then started again. The problem has never begun again if the truck is left overnight without starting or at least a few hours.

The flywheel has all of its teeth and is in great shape (though not for long if this keeps happeneing.)

Any help or insight will be greatly appreciated.

Answer 1

Strange problem indeed!
The weird part is the pattern of the problem.
Is the starter dragging,or is there an actual starter drive to flywheel meshing problem.
It is heat related. That's why it does it only on a restart after not sitting very long.
Is the engine running hot?
Is the timing set correctly?
Any modifications to the engine that have raised the compression?
I know that I'm answering a question with more questions,but I am trying to offer some things to look at.
Also check to make sure that the battery is good.
Make sure all of the cables,positive and negative are clean and tight.
Check the negative cable at the engine block. Grounds are very important and can cause unusual problems.
Hope this helps.

Answer 2

One of the first things you should check is the timing, if it is set too far advanced the engine will fight itself trying to start when hot, it won't do this cold . Also GM put a little brace between the starter and the block at the end of the starter if this is missing the starter could mis-align causing the gear gnashing. Third make sure you are putting in the right starter, a 305 has a smaller flexplate than a 350 so you should be sure you do indeed have a 305 as opposed to a 350.

Answer 3

Replace starter with ONLY NEW AC/DELCO!! I can't begin to tell you how many junk autozone, o'reilly's, pep boys, etc "reman" starters I have seen bad out of the box. Double check ring gear on flex plate and make sure that the starter mounting area on the block is not cracked. Also, for what its worth, make sure you don't have a bad head gasket. Coolant can leak into cylinder and cause a hydraulic lock effect. I have seen this happen and literally break the starter off of the block. Good luck.

Answer 4

Bad cables can do that. A bad connector will heat up and reduce the current to the starter. It kicks in when you turn the key, but the voltage drops right away and you don't get good engagement. It works better when it's cold because the bad connector has a chance to cool down. It would be the battery/solenoid, solenoid/starter or ground cable.

Answer 5

Check the teeth on the bendix drive in the starter and if it shows any signs of wear replace it.

I would have bet on your flywheel/flex plate being messed up on the teeth. the mechanic said it was OK????

Then put in a new starter bendix drive, they are crap and can be bad out of the box.

A qualified rebuilding shop can check if the arm from the solenoid is cracked/bent when changing the drive bendix. hey it happens and kicks local tech butts when it does!

Man I still would want to see the teeth on the flywheel/flexplate, you have had the problem so long that something has got to have happened to it.

Good Luck, It ain't a real mystery, I swear.

ASE Auto tech 30 years

Answer 6

sounds like maybe it is getting to hot and breaking down. maybe the exhaust is running to close to the starter and the heat is affecting the starter. not sure just a guess. but be sure to let us know. never heard of this problem before.