280z Halfshaft shortening for R200 conversion

[Lazeum]

I'm in the process of swapping a R200 onto my 72 240z.

I just wanted to share how I managed to reduce the length of my 280z halfshaft since I haven't seen many "how to", the ones I've seen did not do the trick for me (you lucky US guys with nice machine shops ).

 

I've got 3 different shafts available. At first I thought one of them was shorter since they did not collapse all the same way. In order to find out, I've disassembled them all. All needed new U-joint, boot & paint anyway. I found inside them grease mixed with water and rust because of boot being broken, it made an emulsion and become almost solid (like soap). Design of the shafts was slightly different (taper before the splines) but overall length was the same for all.

 

Let's get back to the shaft shortening.

My first attempt was to use a lathe and mill the end of the inner shaft to reproduce the tip. Member 2126 has done it so it is possible but I faced 2 issues:

- Lathes available were too small to handle the width of the U-joint fourche.

- Hardened material + interrupted cut made the work very difficult. Tool did not resist. We did not even insist with carbide bits. It was not my tooling, I did not want to destroy everything...

 

Other solution considered would be to cut the end of the shaft and weld the "star" washer. Since material are not the same, I was worried about strenght of the weld + I would have lost serviceability (we are disassembling every day our halfshafts, aren't we? )

 

So my solution was to cut the shaft 0.5" shorter starting from the end of the splines with an wire EDM process (electro erosion). (You can also see the result of my first attempt with the lathe at the end of the splines, we removed 0.1mm prior to stop)

 

 

Then I choose to drill a hole and tap it since only outer metal is hardened to fit an M8x1.25 10.9 bolt.

 

 

Then, I've created an insert from mild steel to recreate the tip of the inner shaft with bolt shape head to make it centered. Washer is still free to move and rotate. Loctite will be used to make sure bolt does not move when everything is reassembled.

 

 

I still have to chamfer the tip of the shaft if I don't want to cut the boot I'll have to put back on. this is an easy task.

 

I'm only concerned about the bolt head size. If it doesn't fit (which I highly doubt since 0.5" might be way enough), I can still redo the spacer and use a tapered head bolt instead.

 

I believe this solution can be made by any shop that has cutting tools and a standard lathe. So I'm pretty happy with my method

 

I have attached as well the drawing of the insert for whoever that wants it.

[JMortensen]

If you weld the end on, why is the shaft then "unserviceable"? What do you need to do that requires taking the star washer (I prefer "ball cupper") off?

[Lazeum]

you cannot remove the washer and the O-ring that go into the outer shaft. You cannot remove and change neither the boot.

As I said ironicaly, serviceability should not be really a concern

[zcarnut]

Check out this page (address courtesy of Tony D):

 

http://purplesagetradingpost.com/sumner/bvillecar/construction%20page-23.html

[Lazeum]

That's a nice way to do with creative lathe solution

[JMortensen]

you cannot remove the washer and the O-ring that go into the outer shaft. You cannot remove and change neither the boot.

As I said ironicaly, serviceability should not be really a concern

I can see the boot being an issue. I messed with this a long time ago and I don't remember the washer and the O-ring. I thought that it was not an issue though, as the parts would be loose on the shaft and could still be cleaned, you'd just have to remember to slide them onto the shaft before you welded the part onto the end.

 

I think the problem is if you cut 1/2" off the end, and then add 1/4" back, you probably will still have the shaft bottoming. I would be allowing 3/4" additional clearance of an R200 in the back of an early Z. I'm just not sure 1/4" extra travel will cover it.

[Lazeum]

I can see the boot being an issue. I messed with this a long time ago and I don't remember the washer and the O-ring. I thought that it was not an issue though, as the parts would be loose on the shaft and could still be cleaned, you'd just have to remember to slide them onto the shaft before you welded the part onto the end.

 

This is exactly how it works you just have the washer and the O-ring on the way.

 

I think the problem is if you cut 1/2" off the end, and then add 1/4" back, you probably will still have the shaft bottoming. I would be allowing 3/4" additional clearance of an R200 in the back of an early Z. I'm just not sure 1/4" extra travel will cover it.

 

I did not add 1/4" back since there was the o-ring groove also before. Moreover the tavel limit is coming from the ball cupper (I'm learning ) rather than from the tip of the shaft. One of the outer shaft I've got has a round cup to seal the cylinder instead of a flat round piece of metal that would help to clear the bolt head... (hard to explain, a pic would be better but I don't have one currently)

[PETEW]

Lazeum,

So does shortening the shaft help keep the shaft from bottoming or binding? You kind of make it sound like it may not. What is the issue, if not?

 

Do you have to shorten the shaft for cars that are on lowering springs, or is this mainly for cars using coil overs. I am assuming that stock height cars would not need to do this. Thanks.

[johnc]

http://www.betamotorsports.com/benchracing/R200handling.html

[Lazeum]

I haven't installed the R200 so I'm not able to get any conclusion yet.

 

I followed John's comments on his website about handling. Since everything was disassembled, I though I'd better be safe than sorry

I do have lowering springs and shocks but no coilovers

[toyoz]

John -

 

Using the information in your post #9 (Betamotorsports), it looks like you could shift the rear end over toward the passenger side by .437 and this would give you equal length shafts. The extra .437 at the short end would cure the bottoming out problem. This would, of course, require a new or modified mustache bar. This could cause some alignment (vibration) problems, but I doubt it. Your thoughts?

 

Ernie

[johnc]

I try to line up the transmission and differential when viewed from above. If the engine/transmission centerline is in line with the pinion shaft/gear centerline you've eliminated 90% of any potential driveline vibration problems.

[lgoodson@pacbell.net]

On this subject, do the 300zxt (z31) CV's still have the bottoming out problem. Jon has said that he has heard that maybe they do still bottom. Does anyone know for sure?

[JMortensen]

On this subject, do the 300zxt (z31) CV's still have the bottoming out problem. Jon has said that he has heard that maybe they do still bottom. Does anyone know for sure?

It took a little digging, I had to search for username mayolives and all threads in the drivetrain area, but here's the one thread I was talking about where he thinks his CV is bottoming. There was another one that went into more depth and had several other people complaining that they were bottoming too, but I can't find it anymore:

 

http://forums.hybridz.org/showthread.php?t=116040

[JMortensen]

Here is the other one I was thinking of: http://forums.hybridz.org/showthread.php?t=132252