Snapped crankshaft

[cookman450]

We'll I have recently purchased a n/a td42 and I am going to fit my factory turbo off my 99gu ute.In the process of removing the old engine the td42t which I knew had a major problem:(:(while I was lowering it with the engine crane I noticed the fly wheel and clutch pack where moving.So i ripped the sump off and found the crank had snapped:(.It had snapped right at the rear of the sixth piston so I pulled off the main crank bearing expecting there to be nothing left only to find the bearing had not spun and was in pretty good shape considering the bloody noise it had made.So was just wondering have any of you guys heard of a crank snapping on one of these engines as I was under the impression there crank was slightly beefed up.What would cause a crank to snap??? I will take some photos and post them up in the next couple of days

[threedogs]

spraying belt grip could cause some issues.
I was led to believe these 4.2s were bulletproof, could it be lack of maintenance.
Got me stumped

[nissannewby]

Have only heard of cranks snapping when heavily modified (300hp, 800-900nm)

[Ben-e-boy]

Have only heard of cranks snapping when heavily modified (300hp, 800-900nm)

And using a viper clutch

I have seen a few cranks at gympie diesel that have hairline cracks around the 6th cylinder

[menace 2]

some serious misuse ?
maybe an original defect that got through
is it snapped clean or twisted ?

[Ben-e-boy]

From what I have heard aswell, big power big tyres, stock gearing and dumping the clutch play a big part in crank damage too

[cookman450]

The ute is very stock no mods at it was owned by a cocky before me one owner from new and when I owned it it only did some very mild beach driving there was a new clutch fitted just before I bought it that could be the problem or maybe the previous owner being a cocky might have towed some heavy loads??.but as to lack of maintenance it looks smick internally very very clean only a tiny bit of metal in the sump which is to be expected after the crank snapping the oil pick up,squirters,etc look like new

[slamnsam]

useualy caused by, abuse (excessive rpm, heavy launching, jumping and landing flat floored) out of balance flywheel or clutch. they are the most common problems

[LaurelTurboDiesel]

The bolt for the harmonic balancer can loosen up

[klompy]

Bet that cocky could tell you some stories,some cockys I know are rough on gear.