td4 m47 snapped crankshaft pics

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john t

Active Member
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basingstoke
a few months ago the crankshaft snapped on my freelander , here are a few pics
the engine a td4, m47, 2001, 110,000 miles , had been running without any problems , serviced and oil changed at the recommended intervals, using fully synthetic oil,i have owned the car from 32k miles , engine stripped down , no sign of any wear,
 

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bet that was making a little rumble on idle!! perhaps even a clunking......must have been a flawed casting. Still at least you got to the bottom of it!!!!
 
Wasn't there an issue with casting flaws on these cranks?

But looking at your picture one would say these cranks are still very flexible, a little help seems to be needed though but all by all very good .... (I wonder who enjoys it the most ???).
 
Given the service history and the fact that the crankshaft is adequately supported by the adjacent main bearings I would suspect partial failure of the crankshaft pulley vibration damper or failure of the journal casting at this point although it seems unlikely that a flawed casting would survive in excess of 100K miles? I'm sure an experienced metallurgist would be interested.
 
But looking at your picture one would say these cranks are still very flexible, a little help seems to be needed though but all by all very good .... (I wonder who enjoys it the most ???).

thought that myself ;)

As for the flaw issue, it would depend entirely how flawed the casting was( i suppose ) :p
 
guys this happened a few months back, i bought a replacement engine from ebay £500 all now working as good as before, ,
have a look under the thread , engine sounds like a hedge cutter
here is the story:- i was driving along about 50mph, and all of a sudden there was this ticking noise, and lost all power ,the engine stopped,
i had to be recovered home by the AA, there appeared to be no compression ,
on investigation , i eventually found the exhaust cam sprocket had come loose, so set about retiming the engine, there was no valve damage as these engines seem to be valve safe,
after a lot of messing about i eventually get the engine to run, although it sounded really bad ,it sounded like the worst case of diesel clatter i had ever heard,all injectors were then removed for testing all working ok , after running it for a short while the crank pully then decides to fall into two pieces ,this was replaced with a new one, the engine started again but still clattering , i gave it a few revs thinking do or die , and bang that was the end of that,,, a snapped crank,
i actually think the engine had been running for this short time with the crank in two pieces or cracked and the big end had been keeping it in place, causing the sprocket to become loosen , when the engine was removed and stripped , there was no damage apart from the crank, the valves pistons and everything else seemed perfect condition, , so i guess its just one of those things
 
I've seen this kind of failure lots of times in highly stressed racing engines. To me it looks like a fatigue failure caused by a slight defect in the rolled fillet radius. It doesn't take much to cause a defect ether, something like knocking the crank pin with a rod bolt or even a bit of swauf in the rolling machine is enough to start a stress crack with the eventual failure of the crank.
 
' after running it for a short while the crank pully then decides to fall into two pieces ,this was replaced with a new one, the engine started again but still clattering , i gave it a few revs thinking do or die , and bang that was the end of that,,, a snapped crank, '

I can't help thinking that the crank pulley failure is the key to this problem?
 
' after running it for a short while the crank pully then decides to fall into two pieces ,this was replaced with a new one, the engine started again but still clattering , i gave it a few revs thinking do or die , and bang that was the end of that,,, a snapped crank, '

I can't help thinking that the crank pulley failure is the key to this problem?

If the crank damper was ineffective then that would shorten the cranks life due to torshional vibration causing stress but the crack in the crank would have propagated from some minor surface imperfection.
 
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