Custom CV Axles

Kalun D · 03-22-04, 05:29 PM

Need some custom built CV axles for my GT40. It has a Porsche G-50 transaxle and late 80's Vette outer hubs. The Porsche end is not a problem but the Vette end apparently is.

This vintage Vette normally has a u-joint, so I need to somehow couple a Vette stub to an outer CV bucket. Some axle builders have said I need to weld the Vette stub to a flange and then bolt that to a CV bucket, other have said they can weld a Vette stub directly to a CV bucket. My thinking is the welded setup would be preferable, less bolted joints.

Two questions.

Is anyone else running early Vette outer hubs to which they've adapted CV axles and if so how did you do it?

Does anyone know a custom axle builder that can fabricate this setup?

Thanks

dave harris · 03-22-04, 06:49 PM

How "early" are the vette components?

All DRB kits use a G50 with an adapter plate mated to a MONSTER stub axle and a U-joint on the other end to mate to the corvette (mine are 87) parts.

I can send you a picture if you need one.

dave harris

Devin · 03-22-04, 06:53 PM

Kalun,

I too have been doing some thinking on this very subject.

I have been recently looking at the Ford IRS (cobra or T-bird) hubs and how they could be mated to a Porsche or Audi transaxle. From what I have seen, they utilize a splined shaft into the hub connected to the shaft via a CV joint as well.

Also looking at the lower connecting arm and how it could also be used to support the hub with modification to the typical frame/suspension design (a dual point attachment to the frame VS a single point). So far just thoughts and no actual drafting or frame mockups...

The later model vette hubs somewhere in the 85-2004 were next on my list to look at a possiblity to do this as well.

I was wondering if a typical driveline shop (a good one of course) could cut and reweld & balance the two ends to either one of the above mentioned halves of the puzzle. It may take some creative manufacturing/mating but don't see why it couldn't be done.

Any other thoughts or experiences?

Dave...pictures are always great!

Devin

scott · 03-22-04, 07:30 PM

I had custom cv flanged, splined axles made. They will allow me to run my M1 ZF w/ its CVs and ERA hub carriers which use c3 corvette bearing units. The one feature I regret is not having one made w/ left hand threads and one w/ right hand threads. Instead, I have "castllated" nuts for positive locking. Probably a non-issue but if you are having custom parts made, why not "swing for the fence?"

I would be willing to share my axles as prototypes if we could find a capable someone to make this change.
Scott Buskerud

Mark Worthington · 03-22-04, 08:33 PM

Call Marti at Raxles. He made a nice set for my Mustang Cobra and he does good work. You could also try GKN; they are an OEM supplier and have done small runs for performance enthusiasts but they will probably be prohibitively expensive at such a low volume.

Gary Gibbs · 03-22-04, 09:16 PM

I know Rick Merz has been very happy with his axles. He has lots of torque and HP and has been running them several years without problem. He has done quite a few high 11 second 1/4 mile passes, etc. Do a search for "Rick_Merz" and then send him a message.

dave harris · 03-22-04, 10:14 PM

Ok, here's some pic's - if you need different views, let me know.
Adapter on trans - about 1 1/4 inch thick

dave

dave harris · 03-22-04, 10:17 PM

Ok, apparently I'm not smart enough to figure out how to post more than 1 pic at a time!??

whole 1/2 shaft

dave

gt40rick · 03-23-04, 07:49 AM

Make an adapter like Dave did but in reverse because the 4 holes will need to be drilled through and countersunk and the 6 holes will need to be drilled through and tapped for a 10 mm bolt.

The adapter can be welded to the flange but put the stub axle in a lathe and use a dial indicator to confirm that the adapter and the stub axle are concentric before welding together. I had to weld my adapter and axle because I sheared the (6) 8mm bolts 5 times before I welded them to together.

I like using CV joints rather than u-joints and since you have to adapt one end or the other the best choice IMHO is to go with CV joints. If you go with CV joints use the 108mm Lobro CV joint that is 40mm thick with a 94 mm bolt circle and a 28x31mm spline (this will match the Porsche axles), these are used on F1, GT, and F3000 applications. They might be pricey at $150 apiece but they will not break. I know... I have made at least 40 trips down the 1/4 mi with mine and they are still like new, I just cleaned them and inspected them before lubricating and reinstalling them.

If you would like further info call me at 757 494-2137.

gt40rick · 03-23-04, 07:56 AM

Just to clarify... my GTD stub axles had (6) holes tapped for 8mm bolts (they used a smaller CV joint of which I shattered 4 before converting over to the bigger CV joints. The 108mm CV joints come 32mm thick or 40mm thick, 40mm is the way to go IMHO.

dozzoja · 03-23-04, 09:24 AM

You might try IPS in Broomfield CO. I know he makes CV axles for Pantera (with the ZF) an Vipers.

Here is a link... www.ipsco.org

dozzoja · 03-23-04, 09:41 AM

Or a better link:

http://www.ipsco.org/New%20products/New%20Products.htm

Kalun D · 03-23-04, 05:24 PM

thanks for all the replies

"I like using CV joints rather than u-joints and since you have to adapt one end or the other the best choice IMHO is to go with CV joints."

agree

"If you go with CV joints use the 108mm Lobro CV joint"

yes this is one of the choices Taylor Engineering came up with for the inboard.

Just got off the phone with John Hester (apparently his kit release is on time and on course). He researched building a CV axle with a C4 Vette outer and says there are 2 different stock GM one piece outer splined stub axle/CV bucket/bells that have the same C4 spline, but he didn't remember particulars since he didn't use this setup.

Now just have to research what app for this piece from the measurements and also will have to find or have made an axle shaft splined to the Lobro inboard and GM outboard.

IPS has some nice stuff, especially their sway bar mounts, but their axles are specific to the Pantera.

building from scratch is difficult, you spend half your time running around in circles <grin>

Peter Ransom · 03-24-04, 09:43 PM

Hi Kalun, GT40 Australia are currently developing CV Joint Axles that are suitable for Porsche G50 transmissions and Corvette 1984-89 rear hub spidles.
Initially some proto-type sets will be trialled, then production axle sets will be available.
Peter Ransom
GT40 Australia

Devin · 03-25-04, 01:36 PM

How would/could these axles work for mating the corvette hubs with an Audi transaxle??

Anyone have any experience or firsthand knowledge on this?

I'm not sure if a G50 will be necessary or in my budget for my build but am looking at all of the combinations of transaxle and suspension components to aid in the decision making process.

Devin

Mike Dozier · 03-25-04, 06:45 PM

The G50 has slightly different output flanges than the 016,
which would affect the CV fit or the machining of the adapter if the CV is not bolted direct to the trans.

The G50 is also wider than the 016, so longer axles
will be needed with an 016. Not a big deal since axle
assemblies are all custom built anyway.

MikeD

tims · 04-01-04, 11:35 PM

Kalun_D,
I think we are looking for the same part. fortunately I have one, unfortunately I need two for my project. here is a picture CV adapter it mounts to the early corvette stub axle and a porsche 930 CV joint bolts to it. I am looking for this part, but I have found a machine shop to build this part. if you are still in need of a part like this let me know. The initial setup cost is high so the more parts I can have made make it a little easier to swallow. email me at tim@realride.com

mike_starling · 04-02-04, 12:51 AM

Peter,

Am interested ... have your uprights and a G50-52 transaxle. What do you expect these will cost?

Thanks,

mike starling

Kalun D · 04-02-04, 03:44 AM

I found a GM outer CV joint that fits inside the 84 to 89 Vette outer hub. It's off of a 85 to 89 Cadillac Deville.

It fits fine except that only 1-1/4" of the splines engage, with 2" of spline distance available.

The female Vette splines start at the outer nut but don't go all the way back. The male Deville splines start at the back but don't go all the way out to the nut. I don't know if 1-1/4" is enough engagement I need to talk to a drive line expert.

There is supposedly one other GM outer CV that fits the Vette spline but I haven't found it yet. Maybe it will have more spline engagement.

Once the outer CV is resolves all that remains is to custom make a shaft that has the GM outer spline that fits in the GM outer CV and a porsched spline inboard that fits the Lobro joint.

Just have to find time to make some more phone calls and drive to another CV axle warehouse to match the vette hub, you can't do that over the phone.

Peter D · 04-02-04, 09:07 AM

If you really want a really custom job (steel / aly / chrome-aly / carbon fibre) it might be worth a look at :

www.markwilliams.com

They do all types of drive shafts, & even carbon brake setups.

A friend of mine had some shafts made up for a crazy Vette & was very happy with the professionalism & product quality.

Kind Regards,

Peter D.