New theory on heavy thunk

[BlueStag]

So I took the car to the shop for an oil change.

 

I had been dreading bearing failure, and was expecting a thrust washer or a mess of shavings to come out with the old oil.

 

The shop owner has a better theory: a cracked flex plate or a bad bendix drive.

 

Which he thinks makes sense for a heavy thunk sound for a few seconds of running that then goes away.

 

And does not happen each time the car starts.

 

Thoughts?

 

Who's got a spare flex plate in Los Angeles and would like to look over a Triumph Stag with an L6 in it?

[NewZed]

He's saying that the starter gear is getting bound on the flex plate?  Seems like a stretch.  Cheaper to try a new starter first.  You could probably examine the flex plate through the starter hole too.

[BlueStag]

He's saying that the starter gear is getting bound on the flex plate?  Seems like a stretch.  Cheaper to try a new starter first.  You could probably examine the flex plate through the starter hole too.

No, he thinks it is one of two things:

 

The flexplate could be CRACKED.    They have seen it before.

 

Or they think the bendix drive on the starter could be going south.

 

Which is possible.

 

The car has for a long time had an occasional failure of the starter to engage the ring gear cleanly.     A loud crashing sound as the starter gear jumps out at the ring gear but does not engage.    Sounds like hell.

 

All I need to do is wait for the starter to stop spinning then engage again.   Never fails the second time.

 

But it could be at the end of its cycle.

 

Lord knows I favor it being the starter.    What could be easier or cheaper to install?