When to replace a pressure plate...
 

(I'm doing a 3.2 conversion for my '72.) Is there any reasonable way to determine if your pressure plate is getting tired? My clutch was working fine, but the pressure plate has to be at least 15 yrs old. It is an aluminum one (which our host sells for $969), so if it's still servicable, I'd like to reuse it (with a new disc).

Thanks.
Roger

If you're in the midst of such an ambitious project, it's apparent that your level of automotive expertise is high enough to where you pretty much already intrinsically know the answer. I presume that you're desiring a 911 3.2 specific answer. Unfortunately I have none.

However on a general level, I'll offer up an opinion based upon my experiences with Detroit steel dating back some 45 years. R & R'ing a transmission and clutch was a relatively straightforward, half-hour duration task, as removal of the pressure plate could generally be accomplished via removing a tin inspection cover. For performance purposes, it was desirable to also remove the flywheel so as it could be resurfaced and balanced along with the new disk and the pressure plate you were either reconditioning or replacing if the springs were broken or severely fatigued. This might add another half-hour to the job, if that, not counting machine shop time. So, the question becomes centered around how much time and effort is spent on R & R'ing the transmission to access the respective parts coupled to your 3.2 once it's assembled and installed. Are you going to wish that you had gone w/new "while you were in there" ? That's your call.

i would reuse it in a heartbeat if there are no burn marks on it DEPENDING on how the clutch was used over the last 15 years.

I believe the Sachs Power Clutch has some add'l clamping force. So, not discounting what donagain1 says one bit about rolling the dice, I would go for it once some data is collected from the driver of the aluminum clutch. If was tracked or wailed upon then your risk increases.

Here is some add'l data:

http://forums.pelicanparts.com/porsche-911-technical-forum/571622-how-check-pressure-plate-see-if-its-still-okay.html

I have owned the car since '98, and I believe the clutch/pressure plate was installed just prior to my aquisition. As I mentioned, it is an aluminum one (Sachs). I don't know if it is a Power Clutch or not (are all Sachs aluminum plates Power Clutches?). I guess my concern is really driven by age more than anything else. I had the engine out in 2003, and replaced the clutch disc and bearings at that time, reusing the pressure plate. It has always worked fine. I am easy on clutches. I do use the car for 2-3 DEs a year, but I would argue that use is actually less damaging than stop and go street driving.

It looks great. I'll probably re-use it.

Thanks.
Roger

Good point - once you are rolling the stress is reduced. Burn marks/blue hickies would be the indicator for me.

All the best.