chrisc

924 S set up and used for track/DE's - how long should the CV joints last? 5 events, 10 events? Put new axles & joints on car 6 events ago and they are toast. Boots are fine, but lube has thinned.

86 951 Driver

I just know that I have the same CV's in my car for over 5 years. I have drag raced and what not with no problem. Blew a tranny and they are still holding up. Maybe grease them up ever other race. I have never had a problem not even clicking. Knock on wood.

yellowline

How are they "toast?" If you're seeing a lot of shifter vibration (especially in 3rd, when mine really started to show wear) under load, or have inspected the races and found pitting/wear, then they're done. The grease does thin with time.

There are differing opinions on whether or not clicking is a sign of a failing joint (that needs replacement as opposed to regreasing). Some people claim they can get 50 miles from a regreased CV. Some people claim thousands of miles.

J Silverman

What kind of grease are using? I packed mine with redline IIRC, and they are fine 2.5 years maybe 40 or so track days later...

chrisc

Thanks guys, I think you helped me confirm the problem. The races as shot, metal is missing from the outboard left race. There's a perceptible thunk when starting out and a similar sound when crossing the driveway edging into my drive. My guess is when the car was lowered it was lowered too much putting excessive angle on the shaft/joint. I bought brand new, in the box Porsche complete shafts. They have <3000 miles and 6 DE's on them.

speedtek

I have been racing cars with CV's longer than I can remember. I have blown up a few with high torque motors on drag racing. but on cars we road race we have never had a problem as long as they are well greased and dont have excessive play. If you take them apart try to put everything back the way they were. ***** in the same groove. when you try to mix and match the outer and races you might get clicking noises. the only other problem we encounter when racing is improper angle of the joints when cars are too low or high.

chrisc

Bingo! "the only other problem we encounter when racing is improper angle of the joints when cars are too low or high."
Confirms what I think caused the premature failure.

Thanks

Lemming

I've not had a CV failure that wasn't my fault (bolts come loose, exhaust too close to boot, etc) and my car has been dropped substantially. I do take them out and pack them with grease at least once or twice per season (in fact I'll likely do it this weekend).

AlpharettaRK

I've not had a CV failure, ever (I guess I will this weekend now that I've said it) and I've put 60 track days (at least) on them and they were well used when I got the car. I re-packed them when I did the clutch this summer, that's the first I've touched them. If good, synthetic grease was used and you don't have any cracks there's nowhere for the grease to go. There's sure nothing wrong with re-packing like Tim says but I have never felt compelled to do so. They last 100,000 miles in street cars without service, and I'm not sure track cars are really that much harder on them. You have another issue but I have no idea what it is...
Good Luck
Randy

M758

I put a set of 46k mile ones on my 944 spec car in Jan 2003.

77 races later they are still on the car. I have never performed any work on them although I have make sure they are packed with grease over the years as the tranny has been taken out a couple times over that time.

Also my car sits really low so the angles not ideal. Still never an issue. Even with all other 944 spec cars I have never seen or hear of enough problems to cause any concern. I did replace CV joint on my 100k 944 Turbo S street car few years back. It had torn boot. So I replaced the boot and when I did I did not like the looks of the CV joint. So I replaced it too while I was in there. There was not noticealble issue with the car other then torn boot throwing grease around. I did not drive it like that for long. I choose not to look at the other end of that joint as I figured if I did I might want to replace it.

The only issue I have had with CV joints is bolts backing out due to not cleaning the threads enough. So now I check the bolts routinely. Other than that no issues. Some other 944 spec guys may have had a failure or two, but it is not commong. I don't worry about occasional failues on some parts as 90% of the 944 spec cars were junkers before they got converted and sometimes old parts just fail.

SolReaver

If you really drive that hard. Repack the CV's with the good stuff and clean and repack as needed every 6 mo or so. The CV grease does thin with time and temperature. I don't think the angle is the problem. CV's should last you quite a while, check for contamination, a little grit can cause a world of hurt.