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propshaft info help advice
unijacko67 - 22/6/13 at 10:32 PM

I have a prop with cv one end and uj the other and I’m thinking this is causing lots of vibration in the transmission. I searched online and found info saying it would be ok, but have now found info to say it will cause vibration. My fault because I had it made, but the prop shaft company said it should work. Also the flanges are well out of phase, but again though the uj would relive that.

Pretty sure this is the problem, can anyone confirm. Thanks in advance and looks like a quick re make of the prop.

[Edited on 22/6/13 by unijacko67]

ReMan - 22/6/13 at 11:18 PM

In theory, you always need 2 UJ's to provide a the same output as input speed.
In practice the difference may be miniscule if the angles are small, but I suspect that is the issue

unijacko67 - 22/6/13 at 11:32 PM

I think ill raise the nose of the diff to be in phase with the output shaft and see if that helps before making a new shaft then. The theory for the lower nose on the diff was for traction and to insure the pinion was always in oil. Cheers.

Aaron_n_Sim - 23/6/13 at 07:40 AM

you made it, but were you able to accurately balance it?

Aaron

Ben_Copeland - 23/6/13 at 07:50 AM

quote:

My fault because I had it made, but the prop shaft company said it should work.


quote:
Originally posted by Aaron_n_Sim
you made it, but were you able to accurately balance it?

Aaron


I read it wrong first too..

He had it made, so should be balanced

Aaron_n_Sim - 23/6/13 at 08:09 AM

quote:
Originally posted by Ben_Copeland
quote:

My fault because I had it made, but the prop shaft company said it should work.


quote:
Originally posted by Aaron_n_Sim
you made it, but were you able to accurately balance it?

Aaron


I read it wrong first too..

He had it made, so should be balanced



My bad, it's early for a Sunday,7 hectic kids up n about already!, if he had it made its the makers fault

Thanks Ben

owelly - 23/6/13 at 10:44 AM

The angles of the tailshaft and/or the diff will have no effect on the phases of the joints or shaft. The phases are dependant on the U/Js or CV joints and their rotational position to each other.

unijacko67 - 23/6/13 at 10:47 AM

I believe as reman says it does work, but not with the amount of deflection I’m after. No worries, gonna swap the CV for a UJ and a slip then re-balance. Cheers.

unijacko67 - 23/6/13 at 11:02 AM

quote:
Originally posted by owelly
The angles of the tailshaft and/or the diff will have no effect on the phases of the joints or shaft. The phases are dependant on the U/Js or CV joints and their rotational position to each other.


Ok sorry, my terminology probably not quite clear. The output flange and the diff flange are very out of parallel (not talking in or out of line) which I was led to believe is the phasing. I realise the UJ’s need to be in line with each other, but not sure how you would line a UJ to a CV. I can raise the nose of the diff in seconds via the 4 link bars to get the flanges parallel (phasing ?) which is bound to help, but believe (been assured, advised) it will put the power down better of the line with current set up. Cheers and keep the help coming as I’m no expert as you all can probably tell.

Have seen this which looks helpfull. http://jniolon.clubfte.com/drivelinephasing/drivelinephasing.html

Volvorsport - 23/6/13 at 11:19 AM

should work fine with a cv joint . the cv joint takes out any rotational discrepency , but it should be at the back .

your only problem would be finding a joint suitable that runs higher than road speed .

theres a couple i can think of live calibra 4x4 and volvo 960 IRS , im not sure if the higher end quality cars use a similar arrangement ..like merc

unijacko67 - 23/6/13 at 12:02 PM

The cv joint is the original s2000 prop one. It's on the gearbox end and all original, but we took the cv joint of the rear of the s2000 prop when shortening and replaced with a uj. When you say it should be fine is that with the flanges parallel or can they be out like mine are at the moment as I think I may turn the axle to lift the nose. Cheers again.

Volvorsport - 23/6/13 at 12:53 PM

as long as the components are all balanced it should be fine .

the s2000 prop had cv joints at both ends ?

some fwd cars had ujs/cv joints on the front driveshafts , but im thinking do you have a live axle or IRS ?

unijacko67 - 23/6/13 at 01:42 PM

Hi yes the s2000 prop did have cv joints both ends. Ive just altered the axle (lifted the pinion height via turning axle) and made the diff flange exactly parallel with the gearbox flange. Before I re fitted the prop I stuck it in top gear gave it a blip (Speedo wont be accurate, but was showing just shy of 170) with no noise so fitted the prop and repeated the operation and hey presto no more noise so must have been because the flanges were not parallel. Can’t really believe the difference as this morning it sounded like the gearbox and axle needed a re-build. Cheers.

owelly - 23/6/13 at 03:16 PM

As I see it, the U/J would cause the prop to speed-up and slow down for each time the yolk passed 180°. More so as the angle of the U/J increased. Having a matching U/J in phase, with the opposing yolk at 180°, it would cancel out the speed discrepancy. As the CV joint doesn't have the same characteristics it wouldn't cancel out the U/Js change in speed. I could be wrong though....

unijacko67 - 23/6/13 at 04:39 PM

quote:
Originally posted by owelly
As I see it, the U/J would cause the prop to speed-up and slow down for each time the yolk passed 180°. More so as the angle of the U/J increased. Having a matching U/J in phase, with the opposing yolk at 180°, it would cancel out the speed discrepancy. As the CV joint doesn't have the same characteristics it wouldn't cancel out the U/Js change in speed. I could be wrong though....


Cheers owelly, that does make sense. I will see what its like on the road. Cheers for all the pointers.