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Drive Shaft CV's keep breaking

Posted: Sun Sep 27, 2009 4:23 pm
by MD
Anybody else experiencing breakages of CV joints on their race car drive shafts?
So we understand each other, these are the output half shafts from the gearbox.

Any novel solutions except replacement with originals?

Re: Drive Shaft CV's keep breaking

Posted: Sun Sep 27, 2009 6:25 pm
by ar4me
What kind of breakage?

I haven't experienced any issues. Could it be that modification of Dedion has altered distance/angle from hub to transaxle output flange beyond some critical measure. Didn't Kevin mention someone in SA having issues with that on Alfettas?

Jes

Re: Drive Shaft CV's keep breaking

Posted: Sun Sep 27, 2009 7:43 pm
by MD
Jes,

I originally thought it was related to lack of end float for the axles as the car has been lowered to 80mm ground clearance and so the CV's run almsot horizontal. However on checking end float, this was not a problem at all. Secondly, another quick competitor running standard height suspension with similar engine power is also breaking them so that rules out the car height thing as well.

I am starting to think it may be related to axle tramp getting on and off kerbs but this going to be so hard to verify.

Re: Drive Shaft CV's keep breaking

Posted: Sun Sep 27, 2009 7:50 pm
by MR2 Zig
Maybe something to do with the modified driveline and vibration getting to the half shaft cv's???






Yeah i'm reaching here :wall:

Re: Drive Shaft CV's keep breaking

Posted: Sun Sep 27, 2009 9:52 pm
by kevin
You Ozzies are just to rough over there. We have had zero breakages other than the cv that was to closeon a heavily modified dedion.
Are there specific tracks where the rear is getting airborne off kerbs. Not one of our tracks has a highspeed corner with possibilites to get airborne off a kerb.
That ultra light weight alfetta GT(one that was written off after feature in Track & Race) is back racing with modified dedion origional CV's carbon roof etc. Will chat to owner if anything has ever occured. Are the cv's the same side on all cars and match a specific kerb ?

Re: Drive Shaft CV's keep breaking

Posted: Sun Sep 27, 2009 10:46 pm
by MD
Ziggy, as my post says, it happens to other Alfettas (generically speaking) so its not driveline specific. We no longer have a driveline issue, it was sorted long ago.

Kevin, it's always the LHS CV. Most of the corners are right handers.

Re: Drive Shaft CV's keep breaking

Posted: Mon Sep 28, 2009 12:30 am
by Dennis
Overhere everyone has had their problems with the cv's. The solution is the type of grease. I use a special motorsport grease which I've bought some years ago from a WTCC mechanic. Unfortunately, I don't know what type or brand it is as it came in a blank container. It cost me a fortune then (120 euros, enough for 4 joints), but it is bulletproof.

Others here use Redline CV2 with succes. I used to rebuild/replace them every 2 races, but since I'm using better grease I haven't touched them and done about 8 races on them.

Re: Drive Shaft CV's keep breaking

Posted: Mon Sep 28, 2009 1:20 am
by MD
Welcome back Dennis !!

Now that's an interesting perspective I haven't heard about yet until now. Funny thing is some people never have problems with them and yet other like us do.

Ultimately I think it's about shock and the inability of the joint to handle it so yet again I am thinking of inventing, finding, or recycling some ideas that have been used in the past that will do some cushioning here.

Roughly this would mean fitting some kind of dampner like a donut between the CV and the wheel stub axle flange Can't be all that hard.

Seen anything like it on anything? Post a pic here.

Re: Drive Shaft CV's keep breaking

Posted: Mon Sep 28, 2009 4:03 am
by Dennis
Hi Mike,

what grease do you use? Standard grease can't handle the shock, load and heat generated in racing. Then your joint starts to wear out pretty quick.

Redline CV2 grease is inexpensive , even when it's shipped from the US (and it matches the color of your car ;) ). Can't hurt to try...

Re: Drive Shaft CV's keep breaking

Posted: Mon Sep 28, 2009 4:51 am
by Fernando
Hi Mike,

Try AGIP as well and it sounds almost stupid,but replace the clip that keeps it all together. Not sure what you call that little bugger that requires a specila tool to clip it inward then stretches outward upon release to keep the CV in. :oops: :wall:

Mine failed spectacularly at the old Wesbank raceway Kevin ,just after I came off that tight bend at the end of the main straight. It was just smoke and the most horrible sound that had me pukkering up my butt as you can imagine. :shock:

My brother figured it out for me and two beefed up replacements cost me the grnad total of R5-00 which is probarly less than one Aussie Dollar. :D

We also learned the hardway re the grease,Castrol and Shells products just pissed out of the boot,then some nice chap told us to use AGIP,never ever happened again.

Re: Drive Shaft CV's keep breaking

Posted: Mon Sep 28, 2009 7:00 am
by Mats
This is silly, please specify "breaking" better, does it break in half or is it scuffing the races or what? 8)

Re: Drive Shaft CV's keep breaking

Posted: Mon Sep 28, 2009 8:38 am
by Giuliettaevo2
The only breakage i've seen is the cage that holds the balls and if that goes you end up with a horrible sound.

The grease Dennis mentioned is used by most racers over here, they all speak very highly of it.

Re: Drive Shaft CV's keep breaking

Posted: Mon Sep 28, 2009 12:09 pm
by kevin
MD , i would put my R1 on shock wave (all LHS with RHS corners). Stay off kerbs or change your rebound settings.
How about a pic to see the shear .

Re: Drive Shaft CV's keep breaking

Posted: Mon Sep 28, 2009 12:19 pm
by ar4me
Dennis wrote:I use a special motorsport grease which I've bought some years ago from a WTCC mechanic. Unfortunately, I don't know what type or brand it is as it came in a blank container.
Giuliettaevo2 wrote:The grease Dennis mentioned is used by most racers over here, they all speak very highly of it.
Are you referring to the magic motorsport grease from the WTCC mechanic or the previsouly referred redline cv2 grease? If the former, since most racers there use it perhaps someone knows the name of it. I'd be curious to know since I'm about to put together some Alfetta half-shafts for V6.

Jes

Re: Drive Shaft CV's keep breaking

Posted: Mon Sep 28, 2009 12:27 pm
by Mats
You can buy amazing CVJ-grease at the local GM dealer. The grease on the Saab 9-3 Aero driveshafts (V6) is just about the best you can get. The expensive Shell CVJ grease is also very good.

Best solution is always to keep the driveshaft/CVJ cool, put some ducts or something to guide air onto the shaft or CVJ, that makes a huge difference in temp.