Ralt CV Joints

[Bart Perlman]

I need to replace the CV joints in my Ralt RT 5. Upon receiving the ones my prep shop had specified, we discovered that the splines were not correct. After speaking with the very knowledgeable Craig Taylor, he informed me that Ralt, Chevron and a couple of other manufacturers had originally used a proprietary spline (23 tooth versus 33 tooth), in order to lock customers in to their spare parts. These 23 tooth spline CV joints are no longer in production. Now I faced with either making new stub axles, or trying to locate old/new stock of these CV joints. My preference would be to keep the original pieces and find some unused 23 tooth splined CV joints. Any ideas on where to search? Thanks for any input.

[stonebridge20]

Bart, Try JR Mitchel at GMT racing in Connecticut. He preps a BUNCH of RT 1's and may have a line on CV's

GMT # (203)778-8441 Ask for JR ( like jay arr. not junior)

Good luck, Mike

[bobmic]

Bart, Try JR Mitchel at GMT racing in Connecticut. He preps a BUNCH of RT 1's and may have a line on CV's
Good luck, Mike

And please report back for the rest of us RT-5 owners on what you find.

Thanks,
Bob

[Charles Warner]

More to come . . . . you are out of luck. Original 23 spline were from (purportedly - from Ron Tauranac's failing memory) an early Audi front inner CV joint. Never been proven. Unobtanium. Go to TDI. We worked up an exchange set-up using current 411 joints. Requires new axles and 4 CV's. Somewhere around $1k for everything. You can try to re-use old ones but have gthe magnafluxed first. Almost guaranntee they'll be cracked. Sorry for the bad news.

[formulasuper]

Bart, My 83 RT5 evidently has been converted & uses the standard VW CVs. Maybe you can find the axles from a parted out car to convert yours.

[Bart Perlman]

I am waiting for a response from the Racecar Warehouse in the UK, regarding the availability of new/old stock. All of the "normal" sources have been to no avail. Their website states that they bought alot of Ralt, Reynard and other marques stock. Will wait and see. Apparently, most of the RT 5's running today have already been converted to the 33 tooth VW style CV joints. In fact a couple of the prep shops I have talked with didn't even know that the cars originally came with the 23 tooth arrangement. The fact that my car sat in a garage for 10/12 years probably explains why it had not already been converted. Craig Taylor has told me that he can make the axles at, what I consider, a reasonable price. I was just trying to keep the car as original as possible.

[Charles Warner]

Bart,

An RT-5 with the 23 splined CVs is a real poser. They did not come that way. Only the F2/Atlantic cars were so-equipped (AFAIK) since the F3/FSV cars did not have enough power or torque to require the massive 23 spline units. Your car probably was re-fitted with a kit off an RT-4 for some reason. If you have any of the 23 spline parts they may be worth something to RT-1/RT-4/March drivers, as long as they aren't cracked. I doubt Kevan McLurg will have any as his main focus has been on the later Ralts (i.e. F3000 or F3).

My suggestion is to go to Craig, have the axles made (send him one of the current ones, with the CVs, so he can have a good measurement (assuming, of course, the set-up you have now is proper) and buy 4 lightened CVs from him. In fact, I'd check with some of the RT-5 guys to veriify the distances from flange to flange, in case yours is not proper.

[Bart Perlman]

Charles,

You may have solved the mystery. The previous owner (Marty Monier) had converted this car from RT 5 specs to a Cosworth powered RT 4. It still has the Atlantic brakes. He probably installed the 23 splined CV joints.

When you stated "assuming, of course, the set-up you have now is proper", to what are you referring? Caster, camber, etc., shouldn't have any bearing? Terry at Taylor Engineering told me they needed the measurement from flange to flange. I am assuming that this measurement needs to be from the same point on each flange (TDC, etc.) How close does this need to be ( 1/16, 1/32/,1/64)?

Thanks

[Charles Warner]

Bart,

I had forgotten you bought Marty's car. Yes, he converted it to RT-4 specs. I would be fairly comfortable in accepting Marty had done all the proper calculations as to axle length, etc. He had installed a complete RT-4 rear end so the specs would be OK. If you are converting back to SV specs you need to make sure the axles used are appropriate to the spec suspension. I.e. wide track vs medium track vs narrow track. Best setup is wide track front and narrow track rear. Marty knew this so I am assuming the narrow track is what you have on the rear. To be sure of your axle length, have someone measure theirs or, better still, assemble your car without the axles and CVs. Measure the distance from the upright flange to the gearbox flange for the entire range from full droop to full bounce. That will give you the maximum and minimum distances the axles will see under all circumstances. Give Terry these dimensions and they will know the axle length required given the plunges they want to see.

[Bart Perlman]

Charles,

Could you elaborate more on wide track, normal track & narrow track? How does one know what he/she has without knowing the dimensional difference between them? Were they based on the year of production, with earlier cars being updated to the wide front/narrow rear track configuration? Do you have the track dimension for these three variations? And, I am assuming this was accomplished with longer rockers/wishbones? More porridge please..........................

[Charles Warner]

Bart,

A quick measurement of my RT-4 give a track of 56 inches at the rear and about 58 inches at the front. That should be about the right ratio to provide for the rear tires to go through the same sized hole in the airflow. I would guess Marty would have copied those settings fairly closely. You have to remnember that the RT-4 had a wider stance than the RT-5. You need to be sure you are using the proper RT-5 suspension arms instead of what Marty had on the car the last time I saw it. Although. it was my understanding that he put it back to RT-5 specs when he sold it. A quick measurement of the rear track should confirm this. Without having the exact data I would guess your rear track shpould be around 52 inches with the fronts a bit more.