Rootes LSD Option

[AlpineIan]

I just found a Rootes Brochure titles "Sunbeam Performance Options & Competiton Accessories" that lists parts for Alpine, Tiger and Imps. This is a U.S. printed document with the 42-32 21st Street, Long Island 11101 address on the front cover. It does not have a part number or document id number on it.

This list of accessories for the Alpine includes a Limited Slip Differential and Axle Shaft kit - Part number S233204 for $312.00

Description states that it consists of differential housing, carrier housing with spider gears and two specially treated axle shafts. A crown wheel and pinion can be later fitted according to the choice of the owner. This price includes a $50.00 core charge for the old differential housing.

Individually price CWP's are listed as well. 8.889:1, 4.22:1, 4.44:1 and 4.86:1 all at the same price of 43.45 ea.

I found this interesting because I had not seen this documentation before. This brochure was in a folder with documentation fropm the Kimes car.

 

[RootesRacer]

The fact that the axles are a part of the kit leads me to believe, (or more accurately confirms to me) that the axles were not just hardened alpine axles, but rather special 10 spline axles to fit the dana/spicer 23 powr-lok carrier.

Love to see the axles off of one, but I am converting a 1 piece ford axle for my own conversion.

 

[sunbeam74]

I am pretty sure this was one of those kits:

 

[sunbeam74]

I also meant to mention the guy who has Carl Christensen's car sent me the notes that came with the original Alpine that Don Stephan had bought out of Peoria. In the notes, by Willard Clever, he was adapting MGB axles for the Alpine.

I will need to scan these drawings and maybe somebody can shed some light.

Steve

 

[RootesRacer]

That photo pretty much sums up all my assumptions on the factory LSD unit (10 spline special axles, offset/redrilled crown wheel holes).

BTW, MG banjo axles we 10 spline, so it doesnt surprise me on the MG axle thing.

Who owns that LSD?

I'd really love to get the 2 numbers off the casting, as well as some dimensions to make sure I am on the right track.

 

[sunbeam74]

Just let me know what information you need.

Steve

 

[RootesRacer]

Just let me know what information you need.

Steve

Do you own the unit?

I need the casting# and the stamped# from the powr-lok case, both are dana part#s.

If this turns out to match what I have, then I'll need some measurements for the surgery that differentiates the starting point (what I have) versus the ending point (what ultimately is needed for fitment).

Thx

 

[sunbeam74]

Jarrid,

I think I had posted this before regarding this differential. The only stamping on it is a PN of 22507X... It has a diamond shaped mark which I think might be DANA's mark.

Wonder if this could be the Rootes number? The PN for the axle shafts and differential were S233204.

Anyway, if you need dimensions let me know.... however, it will be a while before I have a chance to get to the garage where it is and look at it.

Steve

 

[sunbeam74]

Buck Tripple wrote:

Attached is a picture showingf the two different types of Powr-Loks used in the Dana 23. The one on the left (with the thicker flange) is for 3.73, 3.54, 3.31 etc. while the one on the right is used with the 4:10s (& numerically higher) gear ratios.

I've found two types of identification on them. First, there a number cast into the bottom of the flange for the ring gear. Second, there are a series of numbers stamped onto the upper half.

The one on the left is the version I use. It has "C31068 N" cast on the bottom of the flange and "22502 X" stamped onto the upper half. The flange is .488" thick.

The one on the right would probably be the one used on Alpines. It has C31083 cast onto the bottom of the flange and has "22506" stamped on the side of the upper half. It has a flange that's .408" thick.

 

[RootesRacer]

I went out to the garage and found mine to be stamped 22502X and confirmed the .488ish flange diameter.

 

[AlpineIan]

You know.... I really don't know a lot about LSD units and how they work internally. Only the basics. I'm assuming that the LSD you guys are talking about... the Dana units... are a clutch type unit? While the unit I have from Baugh's is a ratcheting gear type.

I had Stockman go through my LSD and he told me it was a pre-Detroit locker design. He told me it was in great shape and not to break it because it would be hard to fix... no parts etc...

I understand how the LSD works and why it is an advantage to the car, but what is the advantage to the locker typre vs, the clutch type?

From what I understand the Dana units were modified and cut down to fit the Alpine... Right? Seems a lot of work and I'm assuming the benefit would be to have the clutches and not the ratcheting mechanical design.

I've been told by Jack Beason, who raced the Kimes car after Nancy Frost, that the LSD had a tendancy to break axles a lot. Would this have been less of an issue with the Dana unit?

I'm attaching pics of my Baugh's unit. I seem to recall it had no markings on the unit... only the crown wheel. The paperwork called it out as a #GS17.

 

[RootesRacer]

I wouldnt have wanted to tell you, but looks like history and the PO told you allready...

Locker diffs engage very abruptly, and with no slip at all, so it behaves like a welded spool when enough slip occurs to engage them. Since it takes slip to engage them, the inertia of the motor and drivetrain has to go somewhere when the locker locks, and since the internals have no give, the shock has to dissipate somewhere, and the axles are what will dissipate the energy.

On the powr-lok, there is partial lock built in by the clutch pack preload, this gives some axle to axle pull, but the real locking is done by the force of the axle that has the most traction, which squeezes on the clutch pack via a cam. Powr-loks use multiple clutches, which will slip if they have to, lessening any shock on engagement.
The trick to getting the unit to lock is to hammer on the power while entering a corner, but before any traction loss occurs. Once the force is on, the clutches resist slip in proportion to the rear wheel torque. The powr-lok will resist slip in either torque direction, meaning it can prevent slip due to engine breaking.

Either setup is going to require changes to driver style to gain advantage, both techniques will of course differ.

 

[Jim E]

When I busted the rear end in my 3 Eric G. kindly told me to go get a rear end he had in his pile that was out of a car. I fetched it, Eric was not home at the time, took it to the shop and pulled it apart and guess what... it had a locker in it with a 5 something gear. I just stood there with my mouth open...think he got it with a pile of stuff that came with the yellow race car. anyway it had sat in the weagther for years at some point,the bearings were rusty, this rare piece of gold. Took it back and got another carrier. Maybe there are more of these LSD out there than we think I know Eric has at least a couple, and there were two or three of them with the S1 race car I looked at a few years back.

 

[Mike Broome]

Lsd

I fully understand the interest in what was fitted to the early racers, but do remember you can now buy a LSD from Gripper Diffs in the UK which fits straight into our axles without any modification. Mike

 

[RootesRacer]

I fully understand the interest in what was fitted to the early racers, but do remember you can now buy a LSD from Gripper Diffs in the UK which fits straight into our axles without any modification. Mike

No, someone failed to mention that.

I am going to ditch the stock axles, they are a bad and scary design for road racing.

 

[Mike Broome]

Maybe I have been lucky with my car. I compete in hillclmbs and sprints all requiring brutal starts and hard cornering. I am also running 14" 5.5j wires with 185 super soft rubber.

 

[RootesRacer]

Maybe I have been lucky with my car. I compete in hillclmbs and sprints all requiring brutal starts and hard cornering. I am also running 14" 5.5j wires with 185 super soft rubber.

Surely you have, these things broke back in the 60s, based on the design its a metallurgical certainty sooner or later.

So you going to tell us where to get the Gripper Diffs LSD?

They dont seem to have a website and those that distribute for them dont show the rootes application.

The applications I did see make them look like they are ZF style knockoffs.

 

[Mike Broome]

Gripper plate diffs are produced by D R Engineering for Tom Seal. (email: dreng@dsl.pipex.com) For some reason they do not list the Rootes axle but not only have they produced them (I have one in my car) at last years Race Retro they had on display a version with an aluminium body. I believe this saved about 4.5lbs in weight. There was piece in the british motor press that Tom Seal was moving the business to France, but they would still be available. Scaning the latest publications I can no longer see their advert. I need to make contact as my diff is now making strange noises. Tom told me that I should be getting the diff reset for each season and my diff has done 3!

The LSD diff came about by putting in touch the ongoing maker of Rootes axles for the Iranian Pekan with Gripper Diffs. New Rootes axles and diffs have been produced in bulk until the end of 2006. The guy making the axles thought that there would be a good market in Iran, and as he rallies his Alpine and Rapier it would be good for his own motorsport activities.

I will try to get hold of Tom and will post the result.

 

[RootesRacer]

A picture in various states of assembly would be very nice.

I'l like to see the carrier on its own, installed in the pumpkin would be nice to see too.

Some specs on the ramp angles are also nice to know (is it a one way or two way ETC).

Now as far as the peykan stuff goes, are you telling me they never designed a better axle for the aged rootes design? I would have thought that khodro would have been smart enough to figure out a one piece axle in the thirty years they had it on deck.

 

[sunbeam74]

Mike,

In the background over the last few months we have been discussing the possiblity of using a one piece axle (like a ford axles style) that eliminates the separate hub and woodruff key.

The thought is to design a simple "C" retainer that would hold the axle in the housing (you see examples in the Jegs or Summit catalog).

There is a machine shop that will machine a pair of axles fairly reasonable and you simply have the flang drilled with a 4x4.25" bolt pattern.

I think it would be absolutely ideal to combine the Gripper LSD with a set of one piece axles and a retainer.

Steve