Stronger Halfshafts

[MMT1968]

Hi all,

Is there any suggestion for stronger halfshafts to use in a tuned 1275/T9 Traveller with a 4,22 diff?
Any hints welcome

Chris

[ba04ger]

PETER MAY ENGINEERING CAN SUPPLY , THEY ARE BASED BIRMINGHAM AREA

[ba04ger]

JUST CHECKED THEIR WEB SITE ,HALFSHAFTS ARE £460 PLUS VAT

[Blaketon]

I had a set for my MG Midget (Shorter) but replaced them with a set made by Quaife, that have lasted over thirty years and numerous hillclimb starts (Between 1992 & 1997). The Quaife ones had splines at both ends. I am looking into getting some for the Traveller but the issue could be that the drive flange is bulky.

[MMT1968]

Thanks for that quick reply. I had a look at the site and will order the halfshafts to have them here in case my original shafts fail.

Chris

[jaekl]

A couple years back I queried owners and my conclusion was halfshaft failure is more attributed to component alignment than power transmitted or driver style. If you have the original halfshafts that are over fifty years in use, then they most likely will continue to survive behind a 1275.

[MMT1968]

Fingers crossed. But I like to have stronger ones on the shelf, just in case the old ones fail. I had that once on my previous traveller. Not amusing as it doesn’t have a limited slip diff and has to be towed home.

Chris

[philthehill]

The problem with fitting stronger half-shafts is - you move the failure point somewhere else.
Unless you are in absolute need of stronger half-shafts the standard half-shafts are more than adequate.
Having stronger half-shafts on the shelf will not solve the problem of possible half-shaft failure - they need to be fitted to the car.
I would suggest that fitting the ESM anti tramp bars is a more economical and easier job than obtaining and fitting stronger half-shafts.
The sudden grip of a lifted wheel returning to tarmac is a major cause of half-shaft failure. Get rid of the axle tramp and your standard half-shafts will last longer.

[MMT1968]

Hi Phil,
You’re right! I thought about that also because I made some myself for my Morgan +8 and this was a massive improvement. But the ESM bars seem a bit short to me and I don’t see a good option to fix longer ones. The longer they are the better it is obviously.
Anyway, I‘ll think about that.

Chris

[philthehill]

The anti-tramp bars fitted to my Minor and made by myself have been on there for many years and are very similar to the ESM kit but predates the ESM kit by many years.
The bars are of a similar length to the ESM bars and do not need to be longer.
They are attached under the spring at the rear and between plates at the front attached to the spring hanger.
each end has a 3/8" UNF rose joint.
The anti-tramp bars are currently being upgraded to utilise 1/2" UNF rose joints using the same location points.
My anti-tramp bar design has been copied by several Minor owners with great success.
The ESM anti-tramp bar kit is better than not having anti-tramp bars and unless you are prepared to make your own I would fit the ESM kit.

[MMT1968]

Have you got a drawing of that?
The main advantage of these bars is that they guide the axle to an almost strait movement up and down and stop the leaf spring from swinging in acceleration under load thus minimizing tramping of the axle. My Morgan is accelerating like off a sling shot with no tramping of the axle and no divng of the rear of the car and traction is much better also. But these bars are some 60cm long and got their welded fixing point at the axle about 18cm off the turning center i. e. center of the half shafts. By this distance they are much more effective than the ones for the Minor which are mounted under the axle at the mounting bracket for the shock absorbers. But I don’t see another possible position to mount them on a Minor.

Chris

[oliver90owner]

I suffered twisted half-shaft splines in my Landrover but usually not actually broken. I did manage to totally destroy the diff in my Mk1 Cortina (a lot of crown-wheel teeth loose in that diff housing) and I also smashed the gearbox in my Mk1 Escort (a complete cluster change sorted that).

I’ve never actually broken a half shaft and likely never will, as I drive a tad more sedately than 50 years ago.

[philthehill]

I do not have a drawing.
Just worked out what was needed and made the parts.
The anti-tramp bars are very effective and cope well with 135 plus bhp and 7" wide sticky slicks. They have been fitted to my Minor for many years.
Plus the springs are 7 leaf with the bottom leaf removed and they have been reset to lower the car by 2".

[MMT1968]

Thanks Phil,
I’ve just asked because of some measures, would have made it easier.
I‘ll make some my own and use rose joints as these ar working fine in my Morgan. I understand you have used 1/2“ rose joints at last, right?
I thought about 12mm ones which is quite similar.
But now I have a few questions:
- Did you use a tube or massive round steel for the bar itself? I‘d prefer a tube for stability.

- What about a carbon fiber tube and the rose joints glued in with epoxy and tempered afterwards? Would make it all much easier, no welding, much stronger than steel and much less weight also.

- Could I use the bracket for the tele shocks to mount the rose joint under the axle?

Chris

[philthehill]

The original anti-tramp bars were square tube with 3/8" UNF inserts. The new anti-tramp bars are solid steel with right and Left hand threads. They are not much heavier than the original bars. The bars were purchased ready made from McGill Motorsport. The brackets either end were designed and made by me.
Carbon fibre tubes - no - I will stick with what has proven to be a good set up and has held the axle over many hundreds of standing starts and competitive runs.
What tele damper set up do you have?
Phil

[MMT1968]

Hi Phil,
Thanks for your reply. I have Spax adjustables front and rear.
Can you give me the length of your bars please, I‘d like to do some maths.

The strength of a 16x12 CFK tube is about 3 times more than of a 20x3mm steel tube and a glued connection with the rose joints (JB weld) stands some 273kg/cm2 if additionaly tempered even more. (Tempering process: Heat up slowly to 40° in 4 hours, holding 40° for 4 hours, heating up slowly to 60° in 4 hours, holding 60° for 4 hours, let cool down slowly). To my opinion now doubt it will stand the load.

Chris

[philthehill]

The length of the anti tramp bars is 22" between rose joint centres.
The SPAX damper lower mount is not suitable for mounting a anti-tramp bar to as it is not a sufficiently tight fit to the axle. I have a spare set of Minor SPAX adjustable gas dampers with rear mounts so am aware of the mount deficiencies.
The brackets for the rear rose joint are welded directly to the underside of the spring bottom plate which is a tight fit to the spring and spring leaf centre clamp bolt.

tramp bar bracket.JPG (68.8 KiB) Viewed 188 times

[MMT1968]

That looks strong! I‘ll make mine the same way. As I don’t like mod in a classic car that aren’t reversible I‘ll make the front bracket screwed on by the bolt that holds the spring. With a tight fit it should be strong enough also.
And I‘ll make my bars from CFK tubes and 12mm rose joints.

Chris

[philthehill]

It is strong as I like to make sure that it does not fail. There is a lot of loading on that bracket when the clutch is dropped at about 3000rpm.
The front brackets which fit either side of the front spring mount are fully removable and can be reverted to original spec as the plates are only bolted on. Both plates are a very tight fit against the underside of the front spring eye mount bracket to resist any torque reaction. The two bolts holding the pin insert plate are increased in size from 1/4" to 5/16". The 3/8" section of the eye pin holds the outer plate in place with an additional 5/16" bolt added for security.
It all works because of the close fit to the underside of the eye mount bracket. There is no requirement for additional fittings/bolts.
I have used special shaped cone washers/spacers either side of the rose joints for good rose joint articulation.

[MMT1968]

That sounds well and strong. I’m doing the same way but with 22x16mm CFK tubes. I‘ll glue tapped m12 terminals in that will take the rose joints (male) with a locking nut to adjust them in length. I‘m not tempting to do jump starts or races but just a good road going car I can trust in even if it has more than double the power than the original.
Anyway, I have no doubt that this set of CFK-bars with it‘s glued connections to the rose joints will stand the load. It’s a 22mm CFK tube with 3mm wall thickness and in F1-cars just 1mm thickness is common in those pushrods. The main important part is the tempering process that makes the connections as strong. And those pushrods will weigh some 300g each.

Chris