KAM diff locks and axle upgrades

[daddylonglegs]

Red 90, I read the complete thread that you linked on Pirate and while this test procedure certainly proves the relative yield strengths of the Longfields compared to the other various axle types,which I suppose is the main interest of most reading this thread, as an engineer you would appreciate that it is not a satisfactory means of testing the overall durability of an axle shaft assembly as it doesn't apply cyclic forces to them to determin fatigue resistance. It just twists them once until they break. Also, and I acknowledge that this would be of little consequence to most Rover owners, I could not see any post that refers to a UJ shaft being tested at any angle of displacement. In fact they did not test any axles with UJ's fitted, just a bar through the ear holes.
Bill.

[1tonsoup]

Something else which has been queried before, perhaps by yourself Bill(?) is the issue of boring out the stub axles to fit the Longfield 300M stub shafts. Correct me if I am wrong but I thought that this was necessary - I take it the ID of the Toy stub axle is greater than Rovers? Anyway this is illegal in some places and/or is obviously taking strength away from the stub axles.

To go back to KAMs current CV, it doesn't really matter that it is no better than the Rover CV, since you say yourself Will that the AEUs often break at the stub rather than the bell.



Seamus.

[red90]

I could not see any post that refers to a UJ shaft being tested at any angle of displacement. In fact they did not test any axles with UJ's fitted, just a bar through the ear holes.

Yes, they tested the "Birfield Eliminator Kit" which is a UJ replacement for the CV in a Toyota.

I am well aware of what the test is and is aim at showing. In addition to the testing, there are 500 sets in the field. Many of the guys are running up to 42" tires with 200 to 300:1 crawl ratios, SBCs, full comp rigs, etc..... No failures to date. These same people have quickly broken the treated Longfields in the past. This is all the fatique testing your going to see. A little aftermarket manufacturer can not afford a full fatigue testing program.

In general they appear to be as strong as the 30 spline 4340 shafting. This has been shown to be stronger than the Toyota 8" ring gear as the guys are breaking rear R&Ps before the shafts fairly regularly. I'm quite confident this brings the axle component strength beyond that of the Toy 8", which should be safe to 38" tires or so. If you need to go beyond the strength of a Toy 8", then you should be going to other route.

You are very hard to please Bill.

[red90]

Something else which has been queried before, perhaps by yourself Bill(?) is the issue of boring out the stub axles to fit the Longfield 300M stub shafts. Correct me if I am wrong but I thought that this was necessary - I take it the ID of the Toy stub axle is greater than Rovers? Anyway this is illegal in some places and/or is obviously taking strength away from the stub axles.

To go back to KAMs current CV, it doesn't really matter that it is no better than the Rover CV, since you say yourself Will that the AEUs often break at the stub rather than the bell.

We have been trying to convince Longfield to do a run of the CVs in AEU2522 geometry. This would make them a direct bolt in to most people's Rovers. They should be around 15% weaker because of the shaft size reduction, but this should still be stronger than the Rover R&P.

The stub question is addressed here because the whole CV including the stub has been made with stronger materials.

[up2nogood]

The more I read about the various methods of strengthening Rover axle and CV's the more I am left wondering which option is best.

I found the KAM setup as a possible alternative to MD, ARB and JacMac. Turns out it is a very difficult fitting job (well not really, but definitely more work than the others) and the axles are not as strong (I'm going on what you guys are saying here) so that idea went in the bin.

But the fact remains the question was born of a single concept. Why can't I buy good quality, full bolt in kits for diff lock and axle upgrades?
I thought it odd that one would buy an ARB locker then have to source axles from elsewhere. Not a good option.
I am concerned that MD might not continue for too much longer, therefore throwing into question spares. The reality is that they will sell up eventually and the new owner will continue production, so maybe I'm being silly on this.
I have not attempted to contact JacMac yet, but everyone here seems to think dealing with them is like having a wank with a cheese grater. (A pain, and no guarantee you'll get there in the end).

So by posting this query, I was really saying what off the shelf, no machining or reaming required, upgrade can I purchase for front and rear diff locks in my Discovery? I'm only going to run 35's (at the most) and am really only going to be doing touring and medium off road work. I'm not a thrasher, so I won't be looking for ways to break things either.
Or am I dreaming?

[uninformed]

my personal opinion for your aplication would be to fit maxi-drives. every one will tell you i'm biased, even i will. having delt with mal and constantly pestering him i can say is pr is top level as are his products. i don't think him retireing is a issue as when he does the company will be picked up by someone else and it doesn't make sense to go changeing stuff as the reputation has been built on mal and his designes. i think legally a company has to keep spares for products discontinued for 7 years. as for 35's and the driving you do the aeu2522 should cope alright. but if we play we must expect to eventually break something. nothing is perfect especially our driving(mine atleast) all i can say is give maxi-drive a call, speak to mal and voice your concerns. then for yourself you can decide.
cheers, serg
ps i get nothing from mal for this plug other than feeling like i am giving him something back for all his time.

[red90]

Well unless you have serious mods, you won't break the MD stuff itself. It leaves the CV and the R&Ps as weak points. There are currently two CV options available that are bolt in.

1) CV unlimited. These are a Rover version of the 4340/300M Newfield CVs.

2) GBRs full alloy CVs.

The problem with both options is they are expensive. But they should be as strong as the Rover R&P. The reason for discussing the Longfield option is that it is MUCH cheaper plus having the advantage of being based on larger shafting. The reason there is no cheap direct bolt in Rover option is that the market for highly modified Rovers is very very small. The main group of owners are in the UK. They have been brainwashed that small, skinny tyres and little engines are good.....

[daddylonglegs]

[quote="red90"]

You are very hard to please Bill. :)[/quote]

No not too hard to please Red 90. Just a desire to learn more. You see I don't have any formal engineering training. What I know and don't know is a direct result of reading and asking questions.
I would buy Longfield joints in a minute if they made them in a stubless 24 spline configuration ( to suit my portal gears) but that is probably never going to happen.My only hope there is if Kam get their act together.
I was just surprised that Bobby Long didn,t put the UJ vs Longfield issue beyond doubt by testing the D44 and D60 at 30 degrees. I am reasonably sure they would have failed at far lower numbers than the Longfields.
The thread has disappeared now but as a guide to good axle design (necking and polishing between the splines)I was going to suggest that they test a vW beetle or bus rear suspension torsion bar. It would be interesting to see if they would fail or yield within the 180 degree range of the test rig.

[uninformed]

so the range rover cv is two piece. would it be anygood to have the shaft made from hytuff and one of mals new cv rings fitted to the bell. bill i don't know the reasons but i think in the states, some of the guys feel that not necking down between splines is better? i think frankenrover is one of these? red 90 i've been waiting for the gbr 300m cv's but mal is still to see any of these. can you give us specs on the unlimited ones.
cheers serg

[uninformed]

from cv unlimited"The O.E. axle is 1.030/32 teeth at the CV joint. We have upgraded the axle to 1.161/27 teeth at the CV joint.

The heavy-duty axles are close to the same size as a one-ton Dana 60 axle. The CV joint components have been upgraded to a larger size to accommodate the abuse delivered in extreme off road use.

To address the heat treatment problem, we have used cryogenically stabilized aviation grade alloy steel. The internal parts have been heat treated to Rockwell hardness more suitable for off-road use. The critical internal parts of the CV joint are made from a virtually indestructible material called 300M. Although 300M is very strong in its natural state, we are able to increase its effectiveness through our special performance heat treatment"
serg

[daddylonglegs]

[quote="1tonsoup"]Something else which has been queried before, perhaps by yourself Bill(?) is the issue of boring out the stub axles to fit the Longfield 300M stub shafts. Correct me if I am wrong but I thought that this was necessary - I take it the ID of the Toy stub axle is greater than Rovers? Anyway this is illegal in some places and/or is obviously taking strength away from the stub axles.

To go back to KAMs current CV, it doesn't really matter that it is no better than the Rover CV, since you say yourself Will that the AEUs often break at the stub rather than the bell.


Boring out spindles is illegal over here Seamus, but since it is an ''invisible'' modification and strengthwise most people get away with it they go ahead and do it anyway. In my experience only the cheap aftermarket AEU2522's break at the stubshaft, unfortunately usually destroying the spindle too. Genuine ones almost always break at the bell.
so a high strength version of Kams 24 spline stubless Birfield at a realistic price would be definately what the Rover doctor ordered.
Bill.

[Bush65]

so the range rover cv is two piece. would it be anygood to have the shaft made from hytuff and one of mals new cv rings fitted to the bell. bill i don't know the reasons but i think in the states, some of the guys feel that not necking down between splines is better? i think frankenrover is one of these? red 90 i've been waiting for the gbr 300m cv's but mal is still to see any of these. can you give us specs on the unlimited ones.
cheers serg

The 10 spline R606665 cv's have a separate stub shaft, others like AEU2522 have a one piece cv bell and stub shaft.

For a 10 spline R606665 cv, the stub shaft would be stronger if made from hytuff, but the weakness is the small root dia of the 10 spline.

I disagree with the idea of not necking down the axles, between the splines.

There is no point having the majority of the length of the axle stronger than the weakest section at the splines.

Shock loads can easily be greater than the maximum steady load that can be applied through the engine and transmission. A necked down axle will reduce the effect of shock loads on the axle, cv's, ring and pinion.

[up2nogood]

Hmmm, so MD is doing a CV upgrade for around $1,000.

They are using AEU2522's.

Bugger, 'spose that will do the job for now anyway. The test will be if I bust anything....

And before you cry 3.54 R&P I'm going to either 3.8 or 4.1's.

Thanks guys!

By the way, you'd have to ream out the stub axles to fit the Longfields? Would they even fit the Rover diff? Look like they are for Toyota only?

[uninformed]

bush 65 wrote"The 10 spline R606665 cv's have a separate stub shaft, others like AEU2522 have a one piece cv bell and stub shaft.

For a 10 spline R606665 cv, the stub shaft would be stronger if made from hytuff, but the weakness is the small root dia of the 10 spline. "

so john, is the stub shaft 10 spline into the actual bell and when you say small root dia of the 10 spline, is this because of the large course 10 splines removing body from the shaft. would it be possible to bore out the splines in the bell and make a new stub shaft with a better spline design that would also be bigger in dia.
serg

[Slunnie]

Check this with Mal, but I believe the new CV's he is doing with the rings on them are RRC sized with the seperate outer, but I'm pretty sure the inner axle has a different spline count that is large than the 1.1" 10 spline stuff. The necked down dia on the inners is 1.10", though im not sure of the spline count into the CV. I dont know if the CV with the ring will fit into your axles, though perhaps it can be somehow be made to work.

[daddylonglegs]

Serg, in an earlier post on this thread I told about having a CV bell annealed and rehardened in an experiment to check for shrinkage.If successful my intention was to bore out the 10 spline hole and broach it out to 24 splines but the bell shrunk ever so slightly so that I could not refit the balls, cage and spider. It may still be possible to do it but I can't afford to sacrifice about half dozen CV's in experiments to determin the exact reheat treatment procedure.
Bill.

[Slunnie]

I think Haultech are doing this to the AEU2522's for about $300 or $800 inc the CV.

[daddylonglegs]

Apparently not. Certainly they are annealing them a little to make them less brittle, but they aren't soft enough to broach or slot the splines out.

[landy_man]

i believe haultech are only heat treating and welding a ring on the end

[Slunnie]

Sorry, it was only the heat treat bit I meant.

[red90]

On the CV unlimited CVs. The make "Newfields" for Toyotas. They appear to use the same inners with the Toyota 27 spine sized inner shafts. This is smaller than the Rover 23 spline.

[ISUZUROVER]

Surprisingly for a quality optimised product, Longfield don't neck their shafts down between the splines ?

AFAIK most toyota axles are not necked down between the splines, and neither are most American-made axles. I think that is probably the reason the longfields aren't necked down. For some reason many people seem to think that non-necked down axles are stronger, even though that makes no sense. However many axles are made from 1541H which is made into axle blanks and then induction (case) hardened BEFORE the splines are cut and the final machining done. Therefore necking down the axle would remove some induction hardening and possibly cause strength problems.

I am picking up a pair of longfields in a couple of weeks when I am in the US, from Keith at Rovertracks. Keith is in the process of making a full fitting kit with all bits to make the Longfield 30/30 spline CV a direct bolt in to Rover front axles with or without a hilux diff centre (I am not buying this though - making the bits myself - but for people without the machining facilities it could be a good option). Keith has told me that because the stub on the longfield is through hardened 4340, it can be machined to neck down the shaft, thereby lessening the amount of material that must be removed from the stub axle. Therefore the stub axle (spindle) can be machined out just enough so that it is a slight interference fit with the splines on the end of the CV stub.

For those people who do not want to trust a machined stub axle (or be 100% legal in OZ), you can always fit the Jacmac big-bore spindles (about 660AUD a pair). They are only being made in Salisbury pattern at the moment but they wouldn't be hard to modify.

[daddylonglegs]

[quote="ISUZUROVER"]

For those people who do not want to trust a machined stub axle (or be 100% legal in OZ), you can always fit the Jacmac big-bore spindles (about 660AUD a pair). They are only being made in Salisbury pattern at the moment but they wouldn't be hard to modify.[/quote]

Ben, I made the following suggestion on another thread a while back but no one responded. Instead of boring out the Rover spindle to clear a necked down Toyota pattern shaft, why not just pull a 30 spline broach through the Rover spindle instead. Very little metal would be removed as a result and broaching costs work out at about $10 a shot.

I know from costly personal experience not to disturb the surface of induction hardened CV stubshafts. but understood that induction hardening was superior in strength and fatigue resistence to through hardening. After all, the reason most of us Rover enthusiasts are interested in better CV,s is because Rover ones, despite being 2mm thicker than Toyota ones are through hardened and break more easily.
Any comments on the induction vs through hardening debate from knowledgable persons on this side of the world ? I have waded through most of the crap on Pirate, and as with most technical debates, due in part IMHO to bias toward ''good old American made products and know how'' they always remain inconclusive.
Bill.

[ISUZUROVER]

Ben, I made the following suggestion on another thread a while back but no one responded. Instead of boring out the Rover spindle to clear a necked down Toyota pattern shaft, why not just pull a 30 spline broach through the Rover spindle instead. Very little metal would be removed as a result and broaching costs work out at about $10 a shot.

I remember you saying that Bill. I may do that if I can find someone with a toyota 30 spline broach willing to do it. I will have to do a few calcs to work out is the strength difference is worth the hassle though. Do you have the inside and outside diameter of a stock Stage1/110/Rangie stub axle handy?

[Bush65]

Bill,

From what I know of metallurgy.

The strength and hardness of steel is affected by the arrangement of the carbon atoms in the different forms and sizes of the crystalline structure.

As steel is heated and cooled the arrangment of the carbon atoms is transformed (phase change).

As steel with up to 0.85% cabon is heated you have ferrite plus pearlite up to about 700 deg C when it transforms to ferrite plus austenite, then to all austinite (at 900 deg C for low percentage of carbon, to 700 deg C for 0.85% carbon).

If the steel is then cooled slowly (annealing) or in still air (normalising), it transforms back to ferrite plus pearlite.

If the steel is quenched (hardening), much of the austenite can't transform back to pearlite.

It is difficult to retain austenite in low carbon steel because it transforms back to ferrite at a high temperature.

Large parts are difficult to quench, particularly in the middle (this is a heat transfer problem).

Too rapid a quench introduces thermal problems (eg cracking). The big advantage of alloys in steel is they allow the ausenite to be retained at reasonable rates of cooling.

When quenched, some austenite can transform into several micro-constituents. Perhaps the most important is martensite, the hardest constituent obtained in steel. Though hard and strong, its needle like stucture is brittle. This is improved by tempering which relieves the stresses in the structure of martensite.

Cryogenic treatment of quenched steel transforms more austenite to martensite. This should be carried out before tempering.

Regarding induction hardening. The surface is heated to the critical temp for austenite and then quenched.

You could not compare an induction hardened plain carbon steel to a good alloy steel through hardened, because the former would not have the core strength of the later.

Some case hardened steels like EN39B can have exceptional properties, combining a hard surface for wear resistance and very high core strength.

[ISUZUROVER]

Great info John, sometimes I wish I had studied mechanical engineering not chemical, then I would have learnt all that. So if I read between the lines, many steels are more suited to one hardening method than the other, and there is no reason why an induction hardened CV would be better than a through hardened and tempered CV.

[Bush65]

Induction hardening has production advantages.

Stock cv's as far as I know, are plain carbon steel with a fairly high carbon content to achieve the desired hardness after heat treating.

In the case of stock cv's or axle shafts, induction hardening will probably give a similar outcome to through hardening and tempering. It may be that the stubshaft of an induction hardened cv would handle shock loads better. I dont think fatigue life would be much better, because the stress raisers concentrate the stress at discontinuities on the hardened surface.

[daddylonglegs]

Thanks John, Now I am sure you are familiar with Bobby Longs thread on Pirate that Red90 linked us to. Bobby built a test rig to demonstrate and compare the strength of his Birfield joints against other front axle setups including universal jointed dana 44 and 60's. The thread was pulled a few days ago for some unknown reason, but what has stuck in my mind is that all the axles tested failed within the 180 degree operating range of the test rig. Billsta from the Rover Forum on Pirate, the owner of Frankenrover a few weeks ago said that he had some Ashcroft axles on his old Salisbury diff that would twist to 700 degrees before failing and Ashcrofts recommend that they be replaced and kept as spares once the permanent twist exceeded
something like 360 degrees. I also remember many years ago when I worked for a LandRover spare parts dealership that the Dufor sales rep used to claim that their replacement 10 spline axles were good for around 2 turns (720 degrees) before failure. Unless these shafts were made from licorice then I would assume they would be induction hardened as my brain cannot comprehend a through hardened shaft being capable of twisting even 90 degrees before permanent deformation occurs.
Your thoughts ?
Bill.

[daddylonglegs]

[quote="ISUZUROVER"][quote="daddylonglegs"]


I remember you saying that Bill. I may do that if I can find someone with a toyota 30 spline broach willing to do it. I will have to do a few calcs to work out is the strength difference is worth the hassle though. Do you have the inside and outside diameter of a stock Stage1/110/Rangie stub axle handy?

Ben, I don't know what I have been worrying about. I was looking through my collection of Series 2, Stage 1, Rangey and 110 spindles and Rovers productin tolerances are so loose that I found a couple that I could almost tap a Toyota shaft through . There was only 0.2mm difference in the bore of the spindle and the OD of the toyota splines. Rovers finish inside the bore isn't too flash so if you bored it out a little with a good finish you may in fact reduce the chance of failure compared to a stock one . Rover spindle bore 32.2mm Diameter of Toyota axle spline 32.4mm
Bill.

[red90]

For a solid shaft, calculations ar pretty easy.

In the elastic range:

S = shear stress (Pa)
T = torque (NM)

S = T * r / J (equation A)

A = angle of twist (rads)
L = Length (m)
J = polar moment of inertia (m4)
G = modulus of rigidiy (Pa)

A = T * L / J / G (equation B)

say 1.24" diameter, 1m long (close to Rover rear long)
J = .5 pi r^4 = 9.66 e-8
G = 79 e9
S = 400 E6 (yield stress in shear for a decent Q&T steel)

From (A)
T = S * J / r
T = 2453 Nm

A = 0.131 e-4 * T
in degrees A (degress) = 7.5e-3 * T

gives 18 degrees before yield begins.

Or something like that.