Thread: broken crank shalf

welcome

sorry to hear of your heartache...

strikes me as odd that not long after a timing belt is done you lose the crank..

where is the crank gone?

just in front of first piston

if its a auto it could be the drive plate my mate had one crack on a s2 disco made a hell of a knock

Originally posted by pt109
hi. new to this site.1997 300tdi 185000kms aquired 20mths ago . just had timing,a/c and fan belt replaced .covered 1000kms loud knocking noise back to rover specialist broken crankshalf .any clues as to why this would happen as the specialist doesnt and wants 3k to fix

3k to fix is probably about right. Broken crankshafts on any modern engine are very rare, and usually no explanation can be found - presumably a manufacturing fault ultimately, unless there is (rarely) an obvious problem such as a loose main bearing cap. Some things can help find the manufacturing fault - stalling at full throttle for example, or, (and this may be relevant) incorrect valve timing.
The thing is, in a modern engine design, the crankshaft is made much stronger than it needs to be, to be rigid enough to reduce vibration to a minimum, and the bearing between every crank helps reduce stress on it as well.

Too much boost tends to break things on newer turbo motors. However so does lack of oil. There was enough suitable oil in the motor wasn't there ?

ops: Just asking, as it's the only thing that comes to mind that would have the ability to cause that sort of failure in such a short (1000kms) period regardless of previous work.

all oil and water levels ok .repairs have started.any ideas on what to do with the old crankshalf (acts of violence not counted)

When you can inspect the break you may get an idea what may have caused it.
When do you pick it up?

hopefully friday.crank looked like it had been cracked in the center of the break for a long time the outer edges looked like fresh breaks. if i can get a photo i will post it .