Mud-club
Vehicle & Technical => Defender => Topic started by: scatt on September 05, 2008, 20:35:02
-
Im having a bit of trouble with my defender 110 dcpu, its a 2.4 tdci with a +2 lift kit and castor corrected radius arms, cranked trailing arms etc. BUT im getting a nasty vibration at approx 40mph. I was advised to buy a wide yoke prop but this doesnt seem to have cured the problem. ive spoke to lots of people and looked at lots of forums but they all have there own idea. Im really confused and need some help. :?
-
I'll be calling you back monday, just waiting for a reply from my man in LR ;)
:D
-
Lifted with castor correction, I make no wonder you're getting a vibration (more accurately a pulsing in the drivetrain).
You need a Cardan jointed propshaft, that's one with a CV at the gearbox end. The axle end is ok becasue with 3deg correction the bottom UJ is almost straight.
DO a search for threads about Cardan joints, it's a common topic.
-
The castor corrected arms make things worse and 9 times out ten are not necessary on a 2" lift. When you lifted your Defender you increased the working angle of the prop. By adding castor corrected arms you have now dropped the nose of the diff back down increasing the angle at the axle even more. These increased angles and the reason that the the UJ's are now wroking out of sync and this is causing the vibration.
Due to the prop angles of the latest PUMA engine and drivetrain the later Defenders suffer from this more than TD5's which in turn suffered more than TDi's.
The wide angle prop was really bad advice. This just stops it binding at maximum working angles and does nothing for the actual working angles of the prop.
As RRBlues has said, a Cardan joint will help to cancel out the angle differential and stop vibrations. A good custom one from the like of the propshaft clinic that is greaseable will cost about 230 pounds. Don't let anyone advise you to put a Discovery II one on.
Personally, I would take the castor adjusted front arms off and see what vibration is like. If it's gone and steering self centering is fine then I'd leave it at that before spending any more money. I'd also take the corrected arms back for a refund.
Unless you need the lift for bigger tyres, 34-35"+ there is no benefit in putting on a 2" lift and as you've found out it causes more problems. A 1" lift will work fine with tyres up to 35".
Cheers
Steve
-
Thanks for some feed back guys, i ran it for a while without the castor arms because i hadnt bought any and it had a vibration then, BUT the front springs were being compressed more on one side than the other you could also see the dampers sitting a funny angle. So the castor cured that problem and made the steering feel LOADS better, obviously as i now know they have may be contributing towards the vibrations. I ve also been told not to fit disco 2 prop, this is what is causing me so much head ache. :cry:
-
The only reason for not fitting the Disco II cardan prop is that it's a sealed unit with no grease nipples. If you start to use it often off-road it lasts about a year. Hence it's a false economy going for the cheaper Disco II one.
Cheers
Steve
-
The wide angle prop was really bad advice. This just stops it binding at maximum working angles and does nothing for the actual working angles of the prop.
Can somebody explain this a bit more?
Surely if it stops it binding at maximum working angles, then by definition the maximum working angles are increased. Isn't the maximum working angle the point at which it starts to bind?
-
David
What he is saying is a simple UJ working at an angle of say 10 degrees is still working at 10 degrees regardless of whether its a standard UJ which or wide angle UJ capable of working at 30 degrees. At a 10 angle the variations in speed and hence viberations are still the same.
To reduce the vibrations in a prop shaft 2 UJ should be paired, correctly phased and working at the same angle to cancel out the speed variations. In a standard setup this should be done by the UJ on each end of the propshaft, but on lifted and castor corrected setups the UJs end up working at different angles.
-
Yep, Mr Barclay has it spot on.
Quick point of note though from reading the above:
A single hookes-type universal joint (two yokes, one cruciform) is a 'cardan joint'.
A shaft, with cardan joints at each end is a 'cardan shaft'.
A joint consisting of two close-coupled UJs is a 'Double-Cardan' joint.
Might make a difference if you're on the phone to someone. ;)
That aside, Steve and RRB are correct with what they're saying - a wide-yoke shaft was not the solution to the problem - a DC shaft was.
-
Thanks, Chris and Eeyore, it makes perfect sense now. Nearly.
If I understand it right, the idea of a CV (Constant Velocity) joint is also to cancel out the speed changes, hence the name presumably. Do they work in the same way?
And if you have a double-cardan joint (have I got this right? The thing Chris describes) at ONE end of the shaft, and a normal UJ at the other end, surely you end up with the driven end of the shaft going in and out of phase with the driving end? I'm thinking... engine turning at constant speed, driving a double-cardan joint, so prop shaft turning at constant speed; then prop shaft turns a UJ, which turns the diff, but as the UJ isn't giving constant rotational speed (ok, angular velocity) then the diff is going to be speeding up and slowing down all the time. In which case doesn't it make more sense to have one at each end of the prop shaft?
-
Due to the nature of the radius arm suspension on the front of a defender the working angle of the joint at the diff end of the front propshaft changes very little whilst the suspension moves up and down, where as the joint at the transphere box end of the proshaft changes a lot more for the same movement. Using a double cardon* joint cancels out the vibration from the changes at the transphere box end.
As you point out there is the potential for the joint at the diff end to cause vibrations as ther isn't another joint to canle out the speed variation. The reality though is that on a standard setup the working angle of this joint is relativerly small (particually after caster correction by rotating the whole axle) so the vibrations cause by this joint typically go unnoticed amoungst all the other background vibrations.
*or whatever you want to call it, micky mouse if you fancy :lol: its just a name, before getting into the 4x4 comunity I hadn't heard of cardon before, they were all refered to as UJs or Hooke joints. The beauty and complication of language.
-
*or whatever you want to call it, micky mouse if you fancy :lol: its just a name, before getting into the 4x4 comunity I hadn't heard of cardon before, they were all refered to as UJs or Hooke joints. The beauty and complication of language.
I like the explanation :cool:
And yeah, I know what you mean about the language thing. The key is to remember the difference between hookes/uj/ cardan and a double-cardan.
-
So what do you call a prop shaft with a double-cardan at each end? :D
-
So what do you call a prop shaft with a double-cardan at each end? :D
Expensive! :lol:
-
The only reason for not fitting the Disco II cardan prop is that it's a sealed unit with no grease nipples. If you start to use it often off-road it lasts about a year. Hence it's a false economy going for the cheaper Disco II one.
Cheers
Steve
Not the only reason... pretty sure it'd be the wrong length for an 07 Defender ;-)
There's a pro / con argument when it comes to sealed-for-life joints. They are usually stronger than the greasable UJs... they have bigger bearing journals, thrust pads and no grease-way inside to weaken the spider. Greasable UJs are an advantage... provided they are greased... A greasable UJ which doesn't get serviced regularly will often fail earlier than a sealed unit. Sadly, many people don't seem to know what a grease gun looks like !
-
So what do you call a prop shaft with a double-cardan at each end? :D
Expensive! :lol:
I like the explanation :lol: far less likely less likely to get missunerstood than hooke or cardon etc.
-
WOW! thanks for all the info, it looks like i better get a double cardon prop shaft sorted pronto :D. more bloody money :cry:.
Will let you know how i get on with as soon as it comes back from LR.
-
I now have a perfectly drivable defender, the double cardon prop was just the job :D :D :D :D.
-
Hooray!
:dance:
-
as a mater of interest i recently bought a disco 2 double cardon prop from ebay it was advertised as having a new uj fitted when it arrived it had a new greasable uj at the double cardon end..... :-k so that makes a disco 2 prop worth buying in my opinion cost me £80 as and when joints fail i will replace with greasable ones :)
-
Is there any identification of those new UJs so you (and others) know which make/model of UJ to get next time?
-
Is there any identification of those new UJs so you (and others) know which make/model of UJ to get next time?
[/quo
te]i shall see if i can sort that out, to be honest i havnt a clue at moment but will find out asap