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Doughnut with CV joint instead of Uni Joint?
DANMAN - 3/3/14 at 09:06 AM

I was speaking to a guy today about changing my rear propshaft from a standard unit with a UJ at one end and a slider with UJ at the other to a TRT version of the same. I mentioned that I would have preferred to have been able to use a doughnut (or Rotoflex disc or whatever you want to call it) but as they won't work on an angle I wouldn't be able to since the car is live axle which means I can't use it on the reverse box output flange or on the diff input flange and also the front prop shaft is on an angle so same deal there. He then asked me if I had ever looked into using a doughnut on the engine output flange but replacing the front prop shaft with Unis at each end to a shaft with CV joints at each end. Not sure if this would work as he said he has never tried it but he seemed to think that CV joints would be friendlier to a doughtnut than Unis when on an angle. Has anyone out there tried using a CV joint front prop shaft instead of a Uni joint shaft? I don't have a problem going TRT but I am having a prick of a time finding someone in Oz who does them and they also would weigh more than just replacing the front prop and doughnut.
Any thoughts?


mark chandler - 3/3/14 at 09:36 AM

SD1 v8 rover I had 20 years ago had a CV at the gearbox and UJ at the live axle.

This may be a better way to go.


Slimy38 - 3/3/14 at 10:23 AM

I thought CV joints overall were better than universal joints, it's only costs and maintenance that normally stops them being used? I'm not sure how they'd affect things in terms of the doughnut though?


adithorp - 3/3/14 at 01:52 PM

A few tin-tops have used CV joints on the prop (4x4 version Jag X-type is the most recent I've seen). The problem isn't the joint but the boots. A prop to a diff spins a lot faster than a drive-shaft to a wheel and the centifugal forces tend to wreck the boots on CV joints.


Slimy38 - 3/3/14 at 04:40 PM

quote:
Originally posted by adithorp
A few tin-tops have used CV joints on the prop (4x4 version Jag X-type is the most recent I've seen). The problem isn't the joint but the boots. A prop to a diff spins a lot faster than a drive-shaft to a wheel and the centifugal forces tend to wreck the boots on CV joints.


Ah yes you've reminded me, someone posted on here a while back about getting some reinforcing rings for a prop CV joint for exactly that reason.


dave_424 - 3/3/14 at 04:52 PM

Would have thought that a boot like this would have a good chance of standing up to the high speed of a driveshaft

http://www.demon-tweeks.co.uk/Product.do?method=view&n=1986&g=243477&p=117137&c=215&utm_source=Google&utm_medium=Base&utm_ campaign=CV%20Joints%20&%20Accessories&gclid=CKatnsbp9rwCFcGx2wodB6kAwA