CV Upgrade

[Turn & Burn]

Thought I’d share this project.
I’m aiming for 250bhp on my engine build so I thought I’d upgrade to CVs. I’ve not chopped up anything crucial doing this so if it doesn’t work I’ve lost nothing but a couple of afternoons playing in the garage on the lathe. Part of what prompted this was upgrading the diff internal to S15 helicals which requires you to use the S15 stub shafts and which have a 3x2 pattern flange.

I’ve used Sierra CVs as used on early Cossies, they’re dead cheap, and machined up adaptors for each end to go from the Nissan flanges onto the the Sierra Cv. All it needs now are shortened shafts, but until I assemble everything I don’t know what length I’ll need, it looks like these are the only bits of the build that may cost. You can get a Sierra shaft for £30, but it costs a lot to either shorten or get custom length shafts made. Currently looking at about £150/shaft.

In the pictures the gold coloured adaptors were made in steel and passivated, but the second batch of silver ones are aluminium which is an easier option, I may remake the steel ones. The gold adaptors would suit anyone wanting to do a cv upgrade, you would need 4 off adaptors plus the CVs and the shafts. Even with expensive shafts I reckon it could be done for about £600.

 

[moggy240]

Good write up!!!

 

[atomman]

Great bit of work , I've been thinking about going this route to,

when you shorten the shafts do you need the spline an the cir clip groove re-cut ?

 

[johnymd]

Very interesting. It’s great to have some clever members on here that that can also make things.

 

[Turn & Burn]

Great bit of work , I've been thinking about going this route to,

when you shorten the shafts do you need the spline an the cir clip groove re-cut ?

I think the shafts are waisted so the easiest way to do it is cut and friction weld, this is dead easy but I don’t know anyone with a friction welder and I’ve been quoted about £170 per shaft from an engineering company so I reckon it’s cheaper to get custom ones made up. Have u got any contacts for this sort of stuff?

 

[atomman]

I think the shafts are waisted so the easiest way to do it is cut and friction weld, this is dead easy but I don’t know anyone with a friction welder and I’ve been quoted about £170 per shaft from an engineering company so I reckon it’s cheaper to get custom ones made up. Have u got any contacts for this sort of stuff?

We've got friction welder at the Uni but it might be a bit to small , I can cut splines though either on the cnc lathe with a hob or on the mill with a 4 axis,

What did the company quote you for ? shaft machined with splines and then induction hardened on the splines or case hardened ?

have you got any photos of the shafts ?

I'm sure we could come up with something between us that would work

 

[Alphabettispaghetti]

I’ve had quotes for treated custom shafts, I’ll dig it out.

 

[Turn & Burn]

We've got friction welder at the Uni but it might be a bit to small , I can cut splines though either on the cnc lathe with a hob or on the mill with a 4 axis,

What did the company quote you for ? shaft machined with splines and then induction hardened on the splines or case hardened ?

have you got any photos of the shafts ?

I'm sure we could come up with something between us that would work

I’ve had one quote of North West Props for the friction welding and online checked out a couple of companies for one off props which I think will be £150 ea. You can buy a standard Sierra shaft off J&R Props for about £30 ea so if u could shorten one of these successfully you’d be onto a winner, they’re not interested in shortening them so I reckon they’re buying them in. I don’t have a shaft but I think you need to be able to weld upto 25mm dia. I’ll post up a link
I didn’t realise u we’re at a Uni but I’ve seen all the good stuff you can make so assumed u must be in engineering somewhere.

 

[Turn & Burn]

https://www.jandrcvjoints.co.uk/for...92/product/drive-shafts-509/drive-shaft/BAR12

 

[johnymd]

Does that say the shafts are rated at 220bhp?

 

[Alphabettispaghetti]

I did look at taking a subaru driveshaft, cutting it, having one of these https://www.jandrcvjoints.co.uk/for...92/product/drive-shafts-509/drive-shaft/BAR12 cut (as T+B noted above) cut and welded, then just using a lobo outer.

I looked at getting it done here....

http://www.spenco.co.uk/friction.html

 

[Turn & Burn]

Does that say the shafts are rated at 220bhp?

Think it means that particular Cossie was 220bhp. I had 350bhp thro mine without issue (happy sideways days)

 

[Alphabettispaghetti]

Think it means that particular Cossie was 220bhp. I had 350bhp thro mine without issue (happy sideways days)

Also remember its torque that bends things, you'd have about 400bhp n/a to get the same torque as a turbo 250bhp?

 

[atomman]

I’ve had one quote of North West Props for the friction welding and online checked out a couple of companies for one off props which I think will be £150 ea. You can buy a standard Sierra shaft off J&R Props for about £30 ea so if u could shorten one of these successfully you’d be onto a winner, they’re not interested in shortening them so I reckon they’re buying them in. I don’t have a shaft but I think you need to be able to weld upto 25mm dia. I’ll post up a link
I didn’t realise u we’re at a Uni but I’ve seen all the good stuff you can make so assumed u must be in engineering somewhere.

They prob order a job lot at a time to keep price down , you could just make one from some thing like EN24t , I would have to do the stress analysis to see if it was up to the job though but One of my mates has got 2 Sierra cossie's so will see if hes got any shafts lying around to have a look at , and get some measurements off ,

Had enough of working in the real world haha , So got a job in the college of engineering last year , bit of teaching and research work and great holidays to