Half shafts on origional MKI

[Garry]

Guys,
Excuse my ignorance, but I seem to recall that origional GT40's (or some of them) had Universal joints at the transmission and hub on the half-shafts. If you have a picture of these, please post. I used the search thread and can't find anything but CV joints in current builds.
One more question...which is better for maintainence and ruggedness? Anyone please weigh in on this. I value your opinions.
Garry

 

[JimmyMac]

Garry
Here are some old original ones of mine

 

[Garry]

James,
Thank you for the pictures. That's what I was looking for. Does the longer half-shaft bolt directly up to the Transaxle or is there some kind of bushing in place there?
Mike Drew had similar questions on this earlier and there was no response.
One more question for the Forum...does anyone have an opinion on which is stronger over the long haul..the old sytem or the CV's?
IMHO the origional half-shaft design looks very sound and I don't recall hearing of too many failures.
Your opinions are welcome.
Garry

 

[JimmyMac]

Garry,
The splined yoke fits to the wheel hub and the 3-bolt crow foot flange matches up to a Metalastic coupling.
This is fixed to the output flanges on the transaxle as shown.

The rubber Metalastic couplings need regular inspection and cost in the region of £220 each to replace.

There are more modern and better solutions to the rubber donut but retaining those old Spicer half-shafts.

 

[Garry]

James,
Thank you for the great response and the additional pictures. I see what you mean...220 pounds sterling for a part that routinely wears out is very expensive for a regular joe like me. I like the idea of using the Spicer half-shafts though. It looks to be a very strong (and correct!) design.
By the way, we are all watching your build. Post more pictures as you have them please. I can't wait to see your car finished. You are the man!
Garry

 

[JimmyMac]

Garry,
That price reflects how often people ask for those large couplings these days and they actually rot on the shelves.
The smaller Imp and Granada ones are a lot cheaper and cost about £30 because of regular stock turnover.

If I recall correctly, some time ago Fran was using the Spicer style half shaft with a CV joint at the output flange. These sound nice to me and there is no disputing his quality..

As for myself, I will be using fresh rubbers every time.

 

[Mark Clapp]

James, very prudent indeed. But remember this is a family show.

 

[Jim Rosenthal]

The Metalastik joints are totally authentic and also totally obsolete technology. But if you want original, they are what was used on the cars built in the 60s. The Mark V cars have 930-type CV joints. The ML couplings are still made, evidently- hard to imagine there is much demand. The metal hardware for them, again, is made by Jay (I have no relationship with Jay other than as a customer, but AFAIK he is the only one going to the trouble and expense of replicating these kinds of items. And the pieces I have gotten from him are nicely done and they fit).

With as few road miles as these cars get, ML joints will age out of utility before they get worn out. But they will still need replaced at $500 a pop...that will buy a lot of CV joints, which will last decades longer. Not a hard choice IMHO.

 

[JimmyMac]

The ML couplings are still made, evidently- hard to imagine there is much demand

They are manufactured by Trelleborg, a Swedish company and I've just bought a pair.
My UK supplier also sold a further three pairs of these large couplings this week.

ps. Jimbo. reference your Avatar, what is a Mk VI ?

 

[Jim Rosenthal]

Funny you should ask...that is a designation the Safir guys came up with for my car. They decided since it has a Mark I chassis, but several features that are NOT original Mark I, that it should be designated as a Mark VI. (some of those features are in the suspension, the CV joint drive axles, the metal fuel tanks it will have, etc) I suppose it makes sense: it isn't an exact Mark I, but it doesn't have the Mark V chassis either. You could say that it has more in common with a Mark I car than any other, since it has the narrow rear bodywork and the original suspension mounting points without the Alan Mann updates. My car also has a ZF-2 transaxle, not a -0 unit as the originals had. But the distinction is not one that I drew. Since they gave it its chassis number, they have a right to call it what model they please, I guess.

Etc etc etc. Frankly I just want to see it run and get in it and drive it. We are making some progress- on Monday we are going to photograph 1072 and record a bunch of details that we need to know in order to move forward in installing the brake lines, clutch lines, etc etc.

 

[Jay Cushman]

Jimmy those pics are interesting. On the pic of the car did you notice the roughly 1/2" spacers between the donut and the axle? On the pic of the axles themselves, you can see where they had been cut apart and rewelded. I have had alot of those axles go thru my hands and most were different lengths. I know some can be adjusted up with the stub axle retaining stud and nut but that does not explain 1/2". Any thoughts as to why so many variations? I also know suspension settings will dictate small changes a well.

 

[JimmyMac]

Jay,
I have had a personal theory about this one for a while.

The distance between the rear hubs carriers for solid discs and the revision to thicker ventilated discs is different.
The changeover required longer or shorter axle centres and this might account for the modifications to the half shaft or indeed adding bobbin spacers to the stubs.

What do you think, you are the man with the original drawings ?

 

[Jay Cushman]

Well....... I am just not sure at this point and there are so many variations that I think sometimes cars ended up with mismatched parts as that was what was available at that time. Most all Mk1s had the solid rotor with cast in hat bolted to the back side of the hub just the same as the late Mk1 (gulf style) which used a vented rotor with bolt on aluminum hats which still bolted to the back side of the hubs. Most if not all Mk2s had a bolt on hat (either steel or aluminum) that slipped over the outside of the hub and over the pins. Mk1 and Mk2 drive pins are different. Mk1 and Mk2 hubs are totaly different and have the offsets changed to go with which side the hat rides. We know all the lower wishbones are the same length so the only changes could be rear camber settings or adjusted location of the stub axle which can only vary .060 or so with the machining of your bearing spacer. I am making billet rear stub axles now and duplicated original but thought long and hard about increasing the inside radius to increase strenght but ended up deciding that the 4340 billet material was many times stronger than the welded tubes of the axle and the original donuts anyways so kept it original dimensions.

 

[JimmyMac]

Jay,
I don't have time for the MKIIs so cannot comment.

The offset/recess machining on the MKI hub carriers fixing lugs for the solid disc brake shoes is different to those for the ventilated format, we learned this a while ago when we bought a few sets of unused originals to find the differences.

Horizontally, there might also be variations to the widths of those rubber couplings and I also noted recently that your "original" clover plates were rather skinny in comparison to others I have seen, so repeatedly, "one size does NOT fit all" on these cars.

There are many constants on the drawings with the chassis geometry and also the transaxle output flanges and these must be the benchmarks, however I agree with you that all of these other fit-out parts varied to choice.

The drive shaft variations puzzled me for a while and decided that I would probably have to go hunting OEM forged steel ends and I might now have a trickle supply of these.

 

[Brian Coombs]

Does anybody know what size the cross pin is in the universal joint?

 

[Charlie Farley]

Are we talking about the bolts for the doughnuts ?

 

[Brian Coombs]

Are we talking about the bolts for the doughnuts ?

sorry only just seen your reply, I was wondering about the universal joint on the other end of the driveshaft.

 

[Ryan L]

@J is that a fuel crossover valve I see at the bottom of that image?

 

[JimmyMac]

Ryan,
Well spotted.
It's a flapper gate just like the ones inside the surge tank.

 

[JohnM]

Garry,
The splined yoke fits to the wheel hub and the 3-bolt crow foot flange matches up to a Metalastic coupling.
This is fixed to the output flanges on the transaxle as shown.

The rubber Metalastic couplings need regular inspection and cost in the region of £220 each to replace.

There are more modern and better solutions to the rubber donut but retaining those old Spicer half-shafts.

Hi all,
I'm thinking of using doughnuts on a car I'm building and the Metalastik torque capacity data is very conservative imho, so any real word usage on a powerful car would be really useful to me.
Do you know the PCD or the part number of the doughnut in the picture ?
Did they fail regularly, occasionaly or not at all ?
Cheers
John