CV question Grady Help!

[84toy]

Putting together a mixture of parts. I have early hubs off a 69 that are 108mm and the CV joints are quite wide however, they are toast. I have one new axle assembly bought at a swap meet with the same (4) 10mm bolts and two pins, and they are narrower (32mm) with the same 28 spline. I'm sure the CV's will work fine except I don't know what they are to order 2 more. I suspect they are 930 joints. I'm not too worried about the width since they will go on Sway-A-Way axles and they let the CV's float (no inner retainer rings).

So, 28 spline, 10mm 4 bolt, 32mm wide and 108mm diameter. The gasket is on the outside of the bolts. Are these 930?

[Grady Clay]

“28 spline, 10mm 4 bolt, 32mm wide and 108mm diameter. The gasket is on the outside of the bolts.”
The thinner CV joints are probably ’72-’75 911. I read somewhere that the thinner CV joints were to save weight (typical in ’72).

The ’75 and later 930 Turbo has a thicker (than the ’69-’71) to accommodate the fact that the axle is much shorter and thereby runs greater angularity.

The ’75 Turbo and everything after ’76 have 6-bolt CV joints. I think the gasket moved from the inside to the outside at the same time. This is also when Porsche started using the 100 mm 923 (912E) CV joints on most 911s

What car are these going on? I have the 108 mm thick CV joints (’69-’71 911) on 914-6 only axle shafts on my SCCA GT2 914-6. A friend has exactly the same configuration on his 914 with a 406 CID SBC and a Hewland DG800. Both cars have spools in place of the differentials so the CV joints take much more abuse. These seem to last forever with only annual fresh grease and boots.

Best,
Grady

[84toy]

Thanks Grady,
Yep, I am building a 914-6 with a 3.6. I had all the parts from a 69 911S and everything has worked great until I found that the CV's were pitted....I cried. What I "believe" I have new is a replacement axle assembly for a 69-71 but the CV's are certainly narrower but the same everywhere else. The CV's pressed off the axle fine, I just need 2 more but don't know what to order. Perhaps the numbers on the CV's will tell the story?

[Grady Clay]

Paul,

If the CV joints are thinner it must be a ’72-’75. The ’69-’71 measure about 42 mm thick. I say ‘about’ because the one I just measured has the tin boot retainer in place.

I assume you are using the ‘69S 901 or a 914 transmission. A 3.6 is a pretty brutish engine – lots of torque and horsepower.

I would recommend a 916 conversion to a 915. Of course a 930 would be better but the conversion parts aren’t available. I would also include all the Wevo and other up-rates including an electric oil pump, cooler and spray bar. While those parts are pricey, I’m afraid you will go through the 901s like pine logs on a fire.

When you have them disassembled for cleaning and inspection, measure the ball diameter. I used to think the ball diameter followed the CV joint diameter but I now don’t think that is necessarily true.


How about a 6-speed from a Boxter or Cayman?
Can a cable G64 be turned around?

What weight? Should be fun!

Best,
Grady

[84toy]

Grady, I measured both joints. They are identical in every way except width. The ball, cage, and spline are all identical. Ball is 22+mm. I think you are correct, the balls go up in size in relation to the joints. Maybe a 944? Look at this site

That would indicate these are 930 joints but you say the width is even wider?

I know the 915 is stronger but a 901 can be built up (and blown up) many times to a 915. This is street car only, no track days. The Wevo setup is almost $2k alone. If I blow the thing too much, I'll re-think the issue. Most people tell me that if you are not (too) stupid, a 901 will work OK. Many V-8's are running them and the shifting will be so much better. We'll see......

The cost now on this project is through the roof but it's going to be really nice and I can always do a tranny later when the car is running.

Problem with later tranny's is the length

[davidppp]

Hello again, Paul!

Wow, serious torque!

I'm afraid my experince has to bear out what Grady said: its is a very very short mean time between (major) failures on the 901 even with all the good modifications available.

The cost of parts for the 901 is actually very high nowadays..the Wevo conversion , once done, allows the use of much cheaper standard bearings by way of a trade off in cost.

What I think both Grady and I would like to help you avoid is ruining the enjoyemnt of what should be a great car.

I happen to have a Boxter 6 speed here specifically to do a 3.6L 914-6 when time allows ( after reshelling the 69S you kindly sold me!)

They are not expensive and easy to find..there are as usual some issues to adapt..



Kind regards
David

[Grady Clay]

Paul,

I understand. I just don’t like to waste our limited stock of 901.

I think ball bearings are always US spec, sorta like wheel rim diameters, etc. I think the balls in our 108 mm CV joints are 7/8”. It seems I remember the 108 mm 6-bolt for the 930 Turbo had 15/16” balls.

We need a through examination of all the Lobro CV joints for 911, 914, 924, 928, 930 … 950 …997.

In my looking for the published spec on the CV joint change in ’72, I ran across some other interesting facts I didn’t know. The centerline of the axle flange on a 915 is 10 mm toward the nose piece compared to a 901 & 911.

The other is there is supposed to be a 10 mm increase in width between the two axle flanges on a 915. I measure that as only 2 mm. I need to do some more measuring.


David, what issues did you have to deal with fitting the Boxter 6-speed? Starter, etc.

Best,
Grady