Originally Posted by
ALi-B
The diesel, due to its high compression was notorious for crank flex, which in turn hammered the main bearings. The Petrol version had very low compression (so it can run on crap fuel) and inturn the crank and main bearings were less stressed and therefore the petrol engine tended to last longer.
Presumably the flex is nothing to do with the compression ratio - it's the torque output that would cause it.
After all, any piston is pushed downwards with a lot more force than it took to push it upwards... that's where the power comes from!