Cast iron/steel - welding/joining to steel crank?

[no_8wire]

Well, after taking apart my engine what is weird is both the flywheel and crank pulley (cast) is that small section of both have become stuck to the crank at each end.

Heres an example...




And once I managed to remove the crank pulley it the join between the crank and pulley almost looked like a spot weld...


Obviosly I am replacing the flywheel and pulley and repairing the crank, but any ideas on what could have caused this effect?
Crank key etc was still good, and FW bolts were tight.

[RunningRich]

Any signs of anyone doing any arc welding on the engine?

[no_8wire]

I put the engine together myself, and since I have had it in the car, no welding has been done...

[RunningRich]

Steel flywheel or aluminium?

[no_8wire]

steel...

[evil_si]

flywheel has been slightly loose, and been fretting

[fivebob]

I've only seen this happen before on motorcycle cranks that had the atlernator on the end of the crank. If the magnetic "flywheel" came loose on the crank it would arc weld itself to the end of the crank and you had to do a rebuild

In this case I have no real idea why it might happen. Poor earth maybe, and the engine is trying to earth through the clutch. Doesn't make a lot of sense though as there'd have to be easier routes for the earth to take, like the bellhousing.

[no_8wire]

Similar thing happened on between the crank pulley and the crank as well.