CV Driveshaft Question

[roblotus79]

Again, thanks to everyone.

Stu,

Unless I'm reading your post incorrectly, the RD kit does come with the Diff output shafts as well now.

I also chatted with Spyder this morning who have a kit that retains the the inner donut and standard diff output shafts as they believe in insulating the shock somewhat.

I think I am decided in going with the RD kit including their diff output shafts that attach directly with the joint. it's more money for sure, but only marginally if you factor in the eventual replacement of your differential output shafts at some time in your ownership.

From reading a lot of historic stuff here, it sounded like the droop limiting concerns were much less for the Plus 2 versus the Elan plus if I go with the RD kit, the angles are lessened as noted above.

Cheers to all and I hope it goes well. (I brought myself up to speed on all the heating and freezing techniques to help the shafts out of the differential as well) The resources on this site continue to impress greatly.


Thanks

Rob

[stugilmour]

Rob, you have it right and my post above might not have been clear enough.

In the last post above I was referring to the hub shafts that are located in the hubs at the base of the shock towers rather than the diff output shafts. The hub shafts can be left in place when you install the CV kit (and are not part of the RD kit). However, you may have to relieve the three holes in the spider attachment where the rotoflex is presently attached to the hub shaft. They were not built to machining tolerance, but work fine to attach to the flexible rubber donut. Not a big deal to chase the hole with a drill bit or Dremel cutter of some kind.

As your car had a thorough rebuilt you are probably OK with the hub bearings. I thought mine were good, but found out later I had to do them; I think they are pretty much considered a wearing part.

As purely tourist information for you, the hub shafts and bearings changed over the product run, and your car has the later stronger version.

HTH

[nomad]

Sorry for horning in on your thread, Rob, but thanks all for the valuable info!!

Kurt
26/3754

[snowyelan]

Sorry if I missed it, but do any of the suppliers sell a kit that replaces both the diff and hub shafts?

Thanks

[nomad]

Sorry if I missed it, but do any of the suppliers sell a kit that replaces both the diff and hub shafts?

Thanks

Without having everything in front of me I rather doubt that there would be any gain in CV shaft length by making up different hub shafts since they have to mount the brake rotor.The diff shaft is another matter.

From the helpful post from down under it appears I can purchase just the diff output shaft's so I may still be on track to be cheeeep!

Kurt
26/3754

[roblotus79]

Kurt,

I'm pretty sure I saw that RD enterprises also sells standard replacements for both the Hub and Diff shafts ($500) if you wanted to retain the donuts and standard intermediate shaft.

I guess the problem from my persepctive is that by the time you do 4 donuts and just the diff output shafts, you are going to be $1,100ish USD, assuming no bolts need replacing. If you do their CV conversion with diff output shafts it is $1,550. There has been some question marks regarding the quality of the donuts recently from what I gather. So you are exposing yourself to continued donut wear and possible failure in the future to save $450.

Cheers

Rob

[AHM]

They were not built to machining tolerance, but work fine to attach to the flexible rubber donut.

I think it is rather that they are machined to a tighter tolerance than allows for easy assembly. My adapters were CNC machined and the studs pressed in - 4 out of 4 went in without any easing. If they had been screwed in studs they wouldn't have gone together.

Without having everything in front of me I rather doubt that there would be any gain in CV shaft length by making up different hub shafts since they have to mount the brake rotor.

The gain is roughly the same at both ends.
Thickness of the adapter + thickness of the flange - thickness of the new shaft flange. overall gain iro 1 1/2 "

[nomad]

What I meant by my post was that the CV differential out put shaft's used by RD and other's are specifically designed to bolt up to the CV joints and thus eliminate the need for an adapter plate. Therefore one would gain a little length on the inboard end of the half shaft but on the outboard end you still would need the adapter plate to bolt up to the hub shaft that can't be modified because it has to bolt up the brake rotor as well.
Clear as mud????

I don't quite understand AHM's post but I'm sure my thinking is correct on this. If not I'm sure I will be corrected!!

Kurt
26/3754

[AHM]

Kurt,

Easy enough to get outboard shafts made-up incorporating a brake disc flange. You could even get a monobloc VL joint made with the correct stem and do away with having a separate shaft and CV joint.

If you keep the existing outboard shaft and use an adapter plate, then no you won't gain anything!!

[Elanman99]

Kurt,

Easy enough to get outboard shafts made-up incorporating a brake disc flange. You could even get a monobloc VL joint made with the correct stem and do away with having a separate shaft and CV joint.

If you keep the existing outboard shaft and use an adapter plate, then no you won't gain anything!!

When you say 'easy' is that something you have done or looked into?

As far as I can see a shaft with a flange to mount the disk would have to be a clone of the standard shaft (3 lug spider) in order to assemble it.

Ian

[AHM]

When I say easy enough I mean that you have to take a drawing to a machine shop with the capability to make driveshafts. Not as difficult as putting in a 5 speed box or different engine!

Looked into - yes and several other driveshaft configurations. Done no due to budget constraints and the limited gain in doing it - I have sent you PM separately.

I would mount the disc to the shaft /flange before pressing into the hub - ok on the basis that bearing changes are more likely than disc changes.

No reason to be constrained by the existing disc design, but then there become more and more variables.

[nomad]

I see now AHM.
I was limiting my thinking on the matter. One could simply cut off the three eared flange and weld on a flange that would bolt directly to the CV joint. The brake rotor could be mounted on countersunk bolts or stud's or just to threaded holes. As you mention the brake rotor would have to be mounted as the shaft is inserted into the hub but that would not be a problem. If i made the shaft's from scratch I could mount a larger bearing for my 16 upright's. The uprights would have to be modified as well but cutting and welding a new inner flange might be cheaper than trying to source the later 18 uprights.

Kurt
26/3754

[AHM]

I just noticed an issue with my earlier statement - You need clearance for the end of the shaft and inner race at full plunge so any new design needs to allow for this. In the adapter plate design the thickness of the adapter plate provides the necessary clearance so it is not space that can be saved.

Kurt, the difference between the 2 hub bearings is in the sealing arrangement so you might want to look at sealing rather than the bearing.

Thinking about the disc mounting - If you could set the CV joint back further it might be possible to mount the disc to the inner face of the CV joint and with the offset the other way around. Just an idea - No idea if it will work!

[nomad]

Good point AHM, one would have to play with the arrangement and it look's as if there is not that much to be gained.
I haven't gotten to the chassis rebuild yet and was not aware that the only difference between the two uprights was the seal arrangement. I have a grease zerk soldered on to a hypodermic needle for injecting grease under the seal lip of sealed bearing's. Perhaps just a little extra grease now and then would prolong the 16 uprights bearing life. I do know that as my car sits right now the drivers side hub bearings are bad.

Kurt
26/3754

[EnfoKen]

My Elan has the sliding spline/universal type driveshafts that Kelsport and others offer. I've had no issues
but wonder if I should use CV's on the car I am putting together now. Does anyone have experience with both versions?
Pictures added for descriptive purpose .