eclou

A stock Gt3 with no mods lost a crank pulley bolt this past weekend at TWS. Only sign was sudden high coolant temps on track. Driver came in immediately and saved the car.

wbrownie

What would be a good preventative maintenance task on this? Does the part break off or does it just come loose so that checking torque is sufficient?

Thanks.

340Elise

I'm guessing it comes loose.

All I know is that I am glad that I swaped mine out for the RS one along with the RS bolt and washer. I may not have needed these parts, but it made my mechanic have to torque it to the correct spec, and he also used loctite.

So we still don't know the reason why this is happening because we have had several different scenarios now. Some on a stock RS, some on a GT3 with the new RS lwfw and clutch parts but without a change or check of the crank pulley, and now on a regular GT3 with the stock clutch and dual mass fly wheel.

Have we had one happen on a GT3 that had the RS clutch and lwfw installed, and also at a minimum check the torque of the crank pulley? If so, then how about the same scenario, except that the RS crank pulley/bolt/washer was installed with loctite and the proper torque spec?

Either way, it seems to me that if you track your car, you should add to your list of parts to check (safety check and extra maintenance for track driven cars) the crank pulley torque; even if you did not change to a LWFW and even if you have an RS. At least check it once to see if it is correct. Who knows, it could be on its way out and you just caught it in time before your next event.

Stephen

todinlaw

Does anyone have the specks on that so we can do a little follow up??

coryf

I have seen this happen on street 996 gt3's when the driver misses a shift and over revs the engine. The street pulley is too heavy and an over rev zings the bolt loose.

sharkster

Hey folks this is what I've been saying... We really can't say for "sure" that it's because of the LWF. This is the second car I've heard of that was _bone stock_ with the pulley failure. Again, they don't use loc-tite, some person by the name of Helga (or a summer student?) might not have torqued it down enough? Who knows...

normank

This is from my previous post:
Cleaned slightly damaged threads of crank and installed new pulley/pin/bolt/shim and belt. Torqued pulley bolt to 186 Ft. Lbs. and ran vehicle with RPM changes on lift and rechecked torqued bolt. Road tested and rechecked torqued bolt. Cleared all fault memory. Vehicle running to manufacturer's spec.
On the drive home all seemed fine. The real test will be this weekend at Homestead.
I did drive the car at Homestead the following weekend without incident. Porsche N.A. does not specify locktite. Torque seems to be critical and probably should be checked occasionally, but it's a real pain because there is no way to reach it without removing the rear bumper.

Jack

I made an earlier post about this situation -- we've seen this happen at 4 different track days to GT3's with the LWF mod. All have denied any over-rev/missed downshift events.

mooty

great, we have a POS car.
better get my checked.....