[tholyoak]

I'll add my $0.02.

1) These types of crank failures were seen with the M64 (aircooled 964/993) when people pulled off the front (harmonic balancer) pulley and added a single mass pulley when ditching the AC, like the RS versions of these cars came with from the factory. Guess what, with track use, the cranks snapped.

2) The M97 3.8 engines come with a different front pulley that incorporates a harmonic balancer, might be worth looking into if you have a LWF.

3) I'm not sure of the cars Jake is referring to, but most people doing LWF swaps on the M96 platform are not doing them correctly. They simply swap the DMF for the SMF and use a stock unsprung clutch disk. Well Porsche and other manufactures have used SMF for sometime, and guess what, they use a sprung disk. Why? Because driveline vibration and shock has to be taken up somewhere. If there is no sprung component (either DMF or sprung disk) guess where all that shock is transmitted? Right to the crank. So using a single mass flywheel with an unsprung disk is going to make the harmonic vibration issues even more of a problem.

Even if you read the LUK site (the manufacturer of the DMF) they state this was simply done for noise and making cars easier to drive. And yes my car has an Aasco LWF with a sprung disk.

-Todd