Technical starter motor bang

[sprie]

After the engine rebuild, i put the starter motor back on.
When i use my starter motor on occasion when the engine doesn't start, there is a bang / clank type noise when it finishes.
To investigate, i removed the starter motor and tested it on the floor, and there is no such noise. It spins fine and retracts fine.
I reinstalled it, being careful about alignment when bolting it back on. Made sure the bolts were nice and evenly tight.
But the noise is still there. Its a single bang at the end of the cycle.
I can't tell if the noise is there when the engine starts, as the noise from the engine would cover it.
I don't know the history, as i am new owner of the van.

So long as it works, I don't mind the noise - but i feel it isn't a good thing and might lead to failure of a component in the future when i least need it.

Any ideas what could be causing it or what to investigate?

 

[bugsymike]

Strange.
No damage to ring gear teeth?
Can you put your hand on starter safely when someone turns the ignition, to see if noise actually from starter?
Apart from that if injection still possibly over advanced it may be possible for it to kick back, throwing starter pinion back hard? Guessing really.

 

[rayc]

There was a problem with engine mounts on the X250 when it was first introduced in 2006/7. It was called ' bang on start up' and Fiat replaced engine mounts as an 'intervention' i.e. if te customer complained hard enough. It was sorted by about 2012 models. this may not be the problem with yours as it is a much earlier model and has only started after an engine rebuild but worth checking if you can see any problem with the mounts on starting.

 

[sprie]

Strange.
No damage to ring gear teeth?
Can you put your hand on starter safely when someone turns the ignition, to see if noise actually from starter?
Apart from that if injection still possibly over advanced it may be possible for it to kick back, throwing starter pinion back hard? Guessing really.

I took the starter off again, and slowly turned the crankshaft and had a good lock at the ring gear on the flywheel. There was no sign of damage that i could see - there was no bright metal, it all looked dull.
On the starter motor, i can see signs of wear on the end edge of the teeth - nothing dramatic though.
Will monitor when i get the engine ready to run again