Custom 5 bolt stub axles with or with 3/4" offset

[ezzzzzzz]

The first prototypes went back to the manufacturer as scrap. They are producing two new sets of axles with the proper dimensions. These still have a 1.245" -29 spline and the nut is being bumped up to 22mm. I should receive them early next week. The prototype companion flanges (for my Porsche 930 CV setup) are in a local machine shop. Once these are done they will need to be farmed out for broaching. I need some assistance at this point. Several of you are using different CV axles for your S30. I need one each of the 280ZXT and 300ZXT companion flange to take measurements from. I will gladly return these to the rightful owners once I have the info I need. Any offers to help?

[blueovalz]

If I understand correctly, the OEM 4-bolt companion flange is being taken care of (your current prototype flange). Is that correct (I believe thats what you -and me- are using with the Porsche joints)?

[ezzzzzzz]

The companion flange I'm having made eliminates the 4 bolt flange. It will slip onto the stub axle and be held by the 22mm nut. The 930 CV joint bolts straight to it. It is 2.75" thick and 4.5" in diameter. The main concern now is finding a broaching operation that will work with me. Most of these are found in the north like VM Broaching in Chicago.

The stock S30 companion flange can be reproduced if anyone wants to use the early u-jointed halfshafts. I have a few here to get measurements from. The 22mm nut should still fit too. The early halfshaft would be bolted directly to the new solid flange (no nuts, just bolts) the way I figure it. What I'd like to do is produce the 280ZXT and 300ZXT flanges slightly shorter to allow for straight installation of those halfshafts. I don't know if that is viable or not. Ross makes those billet flanges but I haven't done much research to see if reversing the CV innards is mandated for fitment. Seems he would have found a better way if it exist.

[ezzzzzzz]

Well now, I did some quick reading. It appears the 280ZXT can be made to fit with halfshaft mods. The 300ZXT would not be that case. The guts must be reversed to allow adequate clearance from the stub axle nipple/nut. That's a small price to pay for a stouter stub axle.

[blueovalz]

I've looked to see what you did to mount the inner CV to your Differential stub (a bit off topic). Could you provide some photos (off line is needed) of that? It appears you're using an R180? I'm thinking that if I eliminate the outboard adapter, I may see what can be used to eliminate the inboard adapter as well, and loose a LOT of weight in the process.

[ezzzzzzz]

It is a R180 fitted with a Nismo LSD and 4.11:1 r&p. I acquired a pair of diff stubs from an early 80's R180A. It's found in the front end of the Datsun 4x4 trucks. This stub is a bolt-in and has the 6 bolt pattern (280ZXT). In my case, I still needed to make an adapter to fit the 930 CV. If you're running the 280ZXT CV axle then it's a perfect match. This stub could be adapted to fit most any CV. It could also be machined to be a snap-in. It's to the left of the diff in this picture.http://album.hybridz.org/showphoto.php?photo=5284&cat=500&ppuser=11402

[rsicard]

I have been following this string of messages and am VERY INTERESTED as I do not want to replace my S30 280Z 27 spline stub axles after apply too much torque from my V8 conversion with a 300ZXT CLSD center section and turbo half shafts. Hope to see more from this thread.

[ezzzzzzz]

Well, it's been a while but things are progressing. I picked up the prototype stub axles (1.245" OD - 29 spline, 22mm nut and 1.25" OD overall) and 930 CV axle flanges from the machine shop. The pieces look great. The axles have a dual bolt pattern of 4 x 4.25" and 5 x 4.5" and a 19mm offset to match the Z31 5 x 4.5" front hubs.

I now need to ship the flanges to have the internal splines cut. That cost will depend on whether they have a stock broaching tool to match or if EDM (wire cutting) will be required. That cost difference is substantial! The prototype flanges are machined from cold-rolled mild steel. That should suffice my needs as my earlier flange adapters are of the same material. If all goes well, I'll use 4150 to produce additional flanges for the 4 and 6 bolt Nissan CV's. I'll post up pictures this evening of these parts.

[blueovalz]

May I assume that these prototypes would also fit my application (should I wish a cloned set)?

[ezzzzzzz]

Yes. They should swap in place of your present stub axle/flange assembly. I'd have to know how thick your present adapters are to get comparable depth so the axle shafts would not need rework or replacement. Hopefully, I'll get the broaching done quicker than the other work and get a few pieces produced, via CNC machining, for interested parties. Of course, final cost will be the being or end of it all.

 

Oh yeah, I corrected my measurements noted a couple of posts back. The axle OD is stock at 1.25" with the splined area at 1.245".

[blueovalz]

Those are awesome dimensions. This is the smartest option I've seen...elimination of the weak spot with maximum spline size. Have you looked at any of the 930/vw conversion flanges to see if that spline count and size could be cut into your new axles?

 

I'm not very concerned about the thickness of the adapters. My goal is to reduce the mass of the assembly (by removal of the adapter and directly bolting the 930 joint onto the flange), and I feel that your part will do that. I assume that the axle will need to be lengthened as a result (about 3/4"), but that is not a problem either being I recently purchased a spare set that is waiting to be machined for a slightly longer groove position.

[ezzzzzzz]

The axle will remain the same length. The reason is you must have room for the axle nut and axle movement within the CV joint. I looked hard to reduce the length to no avail. The adapter is machined to minimize weigh but retain strength. I did look at the VW/Porsche flanges but never saw anything that might be viable. If the present spline count cannot be accommodated without EPM then I'll consult with the broaching company to see what is available in the 1.245" diameter for mechanical splining. The difference between EPM and mechanical broaching is substantial. Here are the photos. The flange shown is for the 930 CV joint. The tig welding seen in the second pic is there because the bearing flange was too narrow on these prototypes. A ring was machined and welded in place to support the stock outer bearing. Future axles will have this lip machined properly from the start.

[LT1-280z]

ezzzzzzz,

 

Please pardon my suggestions if you're already considered these. I've been watching this thread with interest and I had an "outside the box" thought.

 

The axle will remain the same length. The reason is you must have room for the axle nut and axle movement within the CV joint. I looked hard to reduce the length to no avail.

 

Have you considered flipping the assembly around and have the nut on the outside similar to modern CV axles? With this arrangement the the CV adapter would be part of the stub axle (no nut) and would be installed from the inside. The hub adapter would then be the splined bolt on part.

 

Advantages:

more clearance - longer CV axle shafts

different lug patterns and offsets on the same stub axle by having a selection of hub adapters.

 

Disadvantages:

CV adapter is part of the stub axle so no swapping flanges - see idea below.

If the spline snaps the wheel goes flying - making the spline as large as possible (as you have done) should mitigate this risk.

 

 

 

I have an idea to deal with the CV adapter being fixed to the stub axle to allow for interchangeable CV adapters, I'll have to draw it up to explain it clearly, but basically it will become a three piece unit with the nut on the outside.

 

Tom

[ezzzzzzz]

That is a neat idea and possibly viable too. There are quite a few HP front wheel driven cars that use this axle setup. I will look into it. As far as axle length I see no real gain. As long as it can properly function from full compression to full extension there should be no problems. A big drawback to the S30 rear suspension is the short short LCA.

[ezzzzzzz]

There is much more digging required but I'm seeing this new idea has having flaws. The FWD hub is typically a complete assemby bolted to the spindle. As such, if the axle snaps the wheel remains attached to the vehicle. It is a full floating axle assembly. The idea of an outer flange bolted to the stub axle sounds good until (if) there is a failure. At that point the wheel leaves the scene...not good. It is possible to build a similar full floating rear assembly but the costs outweigh the benefits in IMHO. I'll keep looking into it though because it is a neat idea.

[LT1-280z]

I agree about the axle facture saftey issues.

 

With an over sized spline, thread and nut would this still be an issue?

 

Anyway here's a drawing showing the interchangabe flanges.

 

.

[ezzzzzzz]

It may not become and issue BUT it it ever happened the odds really wouldn't matter. Kinda like getting bitten by a shark due to mistaken identity. You're still just as screwed.

[LT1-280z]

I hear you, and of course there's that pesky little thing they call liability - waved or not if something bad happens they'll come looking.

[zkoresko]

Any progress this month?

 

 

I just read through this thread and I am very interested in a set. I had read that people break u-joints and stub axles with there v8 cars, but I figured with my 1977 280Z L28 NA I was pretty safe. I was wrong. I took my car to a local drag strip this past Sunday and sheared 2 of the caps off of my axle u-joint (no play in joint prior to Sunday). I'm putting in brute force joints, but now I'm worried about the stub axles.

 

I am in the middle of the chop cut portion of my carbed chevy V8 swap on my 71 240z using 300zxt axles and 280z axles. I went to a local machine shop to see if they would be able to convert to 5 lug for me. They said no problem since the axle was made of mild steel. I had it checked and it really was made of weak mild steel. I thought the MMS axles would be virtually unbreakable, but I see that some people have already broken them too. The car is primarily an autocross / occasional track car, but I enjoy going to a test and tune day at the drag strip for fun every now and then. I would like the comfort of having the strongest axles possible back there.

 

When a stub axle breaks on an S30, does the wheel fall off too?

[ezzzzzzz]

I'll address things backwards. If the stub axle breaks at the inner flange (typical) then you'll most likely get to the side of the road before the axle could ever works its way out of the housing. There have been occasions where the outer flange separated from the axle shaft. The wheel just goes away in this case (bad karma).

 

Nothing is unbreakable. I haven't followed the MMS axle posts to see if an evaluation was performed to determine why there was a failure. I hope my axles can perform to comparable satisfaction of the hardcore racers. My future axles will use a 22mm nut vs. the stock 20mm. The axle shaft is virtually 1.25" its entire length (stepped down to 1.245" at the splines and between the bearing seats. The only thing not addressed is a dust collar as found on stock axles. I don't see it as a big issue since the outer bearing in sealed anyhow.

 

The first adapter flanges (930 CV) should be back to me by this week's end. If I'm happy with the results I'll focus on a second set of adapter flanges for the second set of axles already produced. Whether these will be 280ZXT or 300ZX is undecided at this point. I need someone willing to purchase these and test in a real world situation behind a V8 or strong L6. I'll probably approach someone in the local region (SE Va or NE N. Carolina). I have confidence that they will serve well. After that, I'll focus on some new axles and flanges using 29 to 31 splines (higher spline counts don't really add much in durability according to my axle manufacturer). The stub axles are being produced to match the 19mm offset of the Z31 front hubs. They can be produced to 0mm offset too. I'm having them drilled on 5x4.5 and 5x5.75 patterns. 4x4.5 is also an option. Lastly, the Z31 hubs are 5x4.5 and cannot be redrilled to 5x4.75 without extensive and overly costly modification IMHO.