Outer Limits 4x4 Board

Hello there

Another newbie in your midst! I've been following the board for a while with interest, in particular the discussions on CVs etc.

Anyhoo with regard to CVs I wonder what you chaps make of one of KAMs products - namely their CV conversion kit. This uses seperate stub shafts instead of integral ones and KAM promote them as being an easily changeable weak(er) link in the front axle. Now I note that not many people on 4x4 forums like so called deliberate weak links, so can this one be turned into a strong link?

Would it be possible to have the KAM CV bells longfielded and custom stub shafts made up to be much stronger? As far as I can tell the internal cage can be standard AEU parts because they are 23 spline.

Problems already are that the "kit" is not cheap to begin with and I don't know whether KAM will sell you the bells alone. Strike me down if this is a pointless idea!

Seamus.

Do you have any more details? Web link? What is the outer spline in the bell? Maybe they are just selling stock 10-spline Rangie CV's???

Apologies - it was late and I forgot to put a link!

http://www.kamdiffs.com/cv_conversions.htm

The outer stub is 24 spline at both ends so bell will be 24 too.

To be quite honest, I'd put your name down for these Longfield AEU2522 replacements. You'd be able to buy a couple of sets of them and still have change from what you'd pay for the KAM kit. I looked into doing this sort of thing but decided there were other options that'd be cheaper.

now, what IS cool that KAM makes is the LSD/cable locker diff... when in "open" mode it functions as their very effective limited slip diff, but can be fully locked via cable actuator to act as a spool... I think these might find their way into the next rover!

Those CVs look Identical to the ones in my 92 RR except the outer shafts on mine have the flange forged on the end. I wonder if they are bigger? I know when comparing mine against the other type with the shafts incorparated , mine look weak.
Regards
Rob

Sometimes it requires so little torque to break a Birfield bell on full lock that if you designed a stub shaft that would break first it probably would not be strong enough to pull the truck in and out of holes, obstacles and up hills etc in the straight ahead position. But I do like the stubless 24 spline design and if the materials and heat treatment were superior to standard and a ring could be welded on then this is what I have been dreaming of.
Bill.

Have tough modified cv,s in my Rangie havent been able to brake them yet done 3 extreem winch challenge and an Ateco plus a couple of extreem trips and havent broken them yet and alot cheaper than kam call me buisness hours 03 9 7396989 Adrian

no secrets here adrian, what do you do to your cv's to make them stronger
heat, cryo, rings, toy stuff???
david

I e-mailed KAM and asked a few probing questions.

Firstly they told me that (at present) the internal cage/ball bearings of their CVs are interchangeable with the AEU2522.

As for the stub-less bell they told me that they are currently a "similar" material to the AEUs so not much difference if this is true. He then goes on to say

"but we are now starting to produce our CV's (inner and outer parts) with a metal conditioning process to further increase strength and durability, and finishing them with a Formula 1 type external polishing process."

I also asked if the bells were available seperately to which he replied that they were not at the moment, but they have never been asked this before and will consider this once pricing has been worked out.

The rest I will just quote from the e-mail response although obviously I can't be blamed if I accidently copy and paste it wrong! [disclaimer off!]


"The KAM "fusible" stub shaft is, as you mentioned designed to be a "manageable" weak link (not just a weak link !), and many triallers/racers prefer to change a snapped stub in a few minutes instead of the hassle of repairing the CV/Half shaft/diff etc... but of course, not breaking at all would be better......but with the space constraints of a Rover axle, beefing things up can get a bit "tight" ......... As I'm sure you appreciate, as vehicles become more and more powerful, with more torque due to bigger tyres etc a weak link will inevitably be found somewhere down the drive train, so why not manage it ? ..... As mentioned above, we are now having some CV housings specially processed which should give approx 300-400 increase in fatigue and 30% increase in strength, so this should help somewhat. (I would still prefer to have a manageable weak link for peace of mind...as it's only fitted to protect the more expensive parts and reduce down time!)

As regards to when CV's or Stub shafts snap..... It, as I'm sure you aware, this depends as much on driver ability almost as much as the engineering or materials themselves, especially on Rovers... as the halfshafts/CV's are so limited by size compared to say a DANA axle etc.
Booting a 35" tyred race prepped vehicle on full lock, and up against rocks etc is always going to cause problems....!

Our fusible stubs can also be tailored to suit the type of vehicle being fitted to for example :- less radius for STD L-R and greater radius for bigger tyres, bigger engines... etc Of course we can still supply stubs without the fusible link, which are 24 splined type.

To develop our fusible stub "shear" points, we worked in liaison with Maddison 4 X 4 who tested the stubs in their GMC 5 1/2 litre, Rain Forest Challenge Rovers..... Since then we have sold over 100 CV conversion sets and only 2 CV Bells have been broken, so we can claim a 98% success rate (or only 2% Failure if you look at it that way!) A "normal" Rover will not shear the fusible stub unless it is in extreme problems...but it will break before the CV does."


The chap seemed very helpful - Richard Tracy at KAM - so hopefully they will not mind if I pass on this info.

I prefer not to change anything at all (frequently) and therefore went the Toy route...

I'd "like" to think that my weak link is the driveshaft UJ

If the CV's are stock strength at the moment then you can fit the aftermarket AEU2522 copies (allmakes???) which already usually break at the stub rather than the bell/star. You can probably buy quite a few sets for the cost of the conversion kit.

It would be interesting if they start making sets of stronger ones though.

The "metal treating" process they mention sounds like cryogenic treatment.

It all comes down to bang for the buck doesn't it?

I think if KAM sell their CV (possibly a future one made stronger than the standard AEU) plus seperate stubs for less than a genuine or Allmakes CV then it will be a better alternative to both. Unfortunately the stubs themselves are already priced at £46 + VAT so they will have to do better than that.

I would love to have longfield chromo wotsits like everyone else but it comes back to cost again. From what I gather longfield haven't actually committed to making a chromo AEU yet have they?

Seamus.

I have GKN overload protectors fitted to the front of my truck. Makes broken CV's a thing of the past.
Put both lockers in and then full lock and drop the clutch on full power and nothing breaks Sorted

Are these hubs still available, I thought they were discontinued?

No they are not available. He is gloating.

lockers in and then full lock and drop the clutch on full power and nothing breaks

But surely on full lock the CV is as weak as can be and therefore the hubs must slip on very little torque application. In other words when the steering is pointing straight ahead and a lot of torque is applied the hubs slip and you get nothing in terms of front end traction. You can't have it both ways.

Oh but I do want to know - how are those 4.75 R&Ps holding up Ali?

No, the clutches are meant to be used in the rear so are set up for the strength of stock halfshafts.

You can still break CVs on lock if you use the power. But that is not a smart thing to d with stock Rover CVs.

1tonsoup wrote:

lockers in and then full lock and drop the clutch on full power and nothing breaks

But surely on full lock the CV is as weak as can be and therefore the hubs must slip on very little torque application. In other words when the steering is pointing straight ahead and a lot of torque is applied the hubs slip and you get nothing in terms of front end traction. You can't have it both ways.

Oh but I do want to know - how are those 4.75 R&Ps holding up Ali?

Oh they are tops. Working really well. I run a 200 TDi , but we have just put a set on my brothers 90 which runs a 4.2 V8 Auto. And has changed his truck and made it alot better. As for strenght he gave them some crap on a challenge event a couple of weeks ago and they came though with flying colours.

Ali

So little traction on that whole event you could run round with everything locked, as much throttle as you could and still bring the CVs home! lol

Tim

tim wrote:Ali

So little traction on that whole event you could run round with everything locked, as much throttle as you could and still bring the CVs home! lol

Tim

Yeah fair point Tim
But you could still break stuff on the sections

Mmmm, I might just have found a set


I'll stop gloating now