CV joint uprating thoughts

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Ride_on
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CV joint uprating thoughts

Post by Ride_on » 17 May 2018 03:04 pm

My B230FT has just chewed through its first CV joint after a year of drag racing and track days. I may not have rebuilt it perfectly or maybe some damage I missed, but I gave it a good inspection. The other 3 seem fine.

After some reading and inspection I believe that the cage broke and this is a common failure apparently, with some US companies offering upgrades on their standard cages.

We also know the output flange on the diff is a bit of a weak point.

I'm wondering what are sensible upgrade options.

1. Cage upgrade
2. Output flange upgrade
3. Move to standard joints (eg GKN race parts range), means either spine adaptors or new shafts, maybe mounting flange adaptors, and/or new mounting flange adaptor to a bigger CV.

2, 3 would be very expensive and I think worth trying 1 first. An existing part might even fit.
Last edited by Ride_on on 18 May 2018 04:38 pm, edited 1 time in total.
1980 345 DL_______1987 360 GLE (project car restored to GLT spec and B230FT'd)
1984 360 GLT______1987 360 GLT
1983 360 GLS______1989 360 GLE
1985 340 GL_______1986 340 1.4
1985 360 GLS______1995 940 SE 2.3 Turbo Estate (daily)
1987 340 GL 1.7

360beast
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Re: CV joint uprating thoughts

Post by 360beast » 17 May 2018 03:26 pm

Can you try and get a transaxle porsche/Alfa Romeo CV joint adapted as they will be rated for more power?

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SteveP
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Re: CV joint uprating thoughts

Post by SteveP » 17 May 2018 04:16 pm

I'm not sure I'd be going along this route - you might just move the problem elsewhere and break the halfshaft, output flanges, T/T link piece or something else instead :D
1989 - Volvo 360 GLT
1985 - Volvo 360 GLS
2008 - Volvo S60 SE Lux


Ride_on
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Joined: 26 May 2009 05:34 pm
Location: Belfast, N. Ireland

Re: CV joint uprating thoughts

Post by Ride_on » 18 May 2018 04:34 pm

Yeah you can get stuff made, but its expensive. £300 for shafts, £250 for 94mm joints (but probably the same strength)

Incidentally I measured the OD as 94mm for the main CV outer, that controls the bolt pattern

http://race.parts/Catalogue/Drivetrain/CV-Joints

I think the joints are strong enough for my use (so far) and a cage upgrade would really help, I'm gonna look at that more seriously.

That will leave the output flanges the weak point, but frankly drifters are breaking these on 1.4s and it seems quite rare. The other disadvantage is that there are not many replacement parts about (a few for the 24 spline injection one though).

A 94x32mm (33 spline) joint is the smallest in the GKN range, any increase would need expensive adaptors or new flanges at both ends (est £300 each for standard material), and I'm not sure how much space there is in the axle box section. Also we can't make the output flanges (breaking area) bigger, so they need exotic material.
1980 345 DL_______1987 360 GLE (project car restored to GLT spec and B230FT'd)
1984 360 GLT______1987 360 GLT
1983 360 GLS______1989 360 GLE
1985 340 GL_______1986 340 1.4
1985 360 GLS______1995 940 SE 2.3 Turbo Estate (daily)
1987 340 GL 1.7

Ride_on
Posts: 2262
Joined: 26 May 2009 05:34 pm
Location: Belfast, N. Ireland

Re: CV joint uprating thoughts

Post by Ride_on » 18 May 2018 04:48 pm

SteveP wrote:I'm not sure I'd be going along this route - you might just move the problem elsewhere and break the halfshaft, output flanges, T/T link piece or something else instead :D
Yes you move the problem to the next weakest point, but you move it UP torque :)

I've never heard anyone breaking a half shaft
TT link seems to be down to good practice/parts
Flange bolts again good practice/parts

I'm saying most TT links and flange bolts fail (360 flanged nuts) due to bad practice.

I think CV joint regular checks are needed for tuned cars, and loose ones need inspected and diag. Is it wear in the ball mech that causes the cage to fail or does the cage wear and/or just get fatigue.
1980 345 DL_______1987 360 GLE (project car restored to GLT spec and B230FT'd)
1984 360 GLT______1987 360 GLT
1983 360 GLS______1989 360 GLE
1985 340 GL_______1986 340 1.4
1985 360 GLS______1995 940 SE 2.3 Turbo Estate (daily)
1987 340 GL 1.7

Ride_on
Posts: 2262
Joined: 26 May 2009 05:34 pm
Location: Belfast, N. Ireland

Re: CV joint uprating thoughts

Post by Ride_on » 19 May 2018 02:24 am

The axle box section has about 6-7mm clearance in radius to the axle base. So allowing for the cover max 6mm, or max 12mm increase in diameter. Seems like a comfortable max is the 100mm, with 108 perhaps needing a small clearance groove cut from the axle.

The Porsche 930 seems popular at 108mm, but this would need thick adaptors at the diff for the CV bolts to avoid the bearing retainer bolts.
1980 345 DL_______1987 360 GLE (project car restored to GLT spec and B230FT'd)
1984 360 GLT______1987 360 GLT
1983 360 GLS______1989 360 GLE
1985 340 GL_______1986 340 1.4
1985 360 GLS______1995 940 SE 2.3 Turbo Estate (daily)
1987 340 GL 1.7

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SteveP
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Re: CV joint uprating thoughts

Post by SteveP » 21 May 2018 08:14 pm

Ride_on wrote:Yes you move the problem to the next weakest point, but you move it UP torque :)
That is indeed a fair point! Over the last 15 years I've seen perhaps a couple of stock GLT's on eBay with T/T coupling issues but perhaps it is a non-issue in most cases. Saying that someone overseas has also designed a really decent looking uprated equivalent but I can't remember who/where!
1989 - Volvo 360 GLT
1985 - Volvo 360 GLS
2008 - Volvo S60 SE Lux

Ride_on
Posts: 2262
Joined: 26 May 2009 05:34 pm
Location: Belfast, N. Ireland

Re: CV joint uprating thoughts

Post by Ride_on » 22 May 2018 02:10 am

I'm thinking atm my problem is this red CV2 grease, its too dry. Seems its better sticking with standard CV grease.

Correction, I'm going to go with leakage at the flange.

This time I made sure it was clean and tightened progressively and diagonally, also went around twice with the torque wrench. Hasn't leaked yet but havn't been to the track yet. Things get a bit hotter there.
1980 345 DL_______1987 360 GLE (project car restored to GLT spec and B230FT'd)
1984 360 GLT______1987 360 GLT
1983 360 GLS______1989 360 GLE
1985 340 GL_______1986 340 1.4
1985 360 GLS______1995 940 SE 2.3 Turbo Estate (daily)
1987 340 GL 1.7

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