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Fitting a R31 Skyline B/W diff to LH/X

Started by _rorym_ , Aug 10 2008 11:00 AM

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#126 _Torrie_Man_

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Posted 31 May 2010 - 07:33 PM


Does anyone know if you could slip a couple of Volvo BW axles into a skyline housing to save redrilling the stud pattern?



volvo axles are 27 spline, totally different size too.


I was under the impression they were 28 spline :dontknow:
Bugger...

#127 _rorym_

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Posted 31 May 2010 - 08:31 PM

Other than that...they are fine..
R

#128 greens nice

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Posted 31 May 2010 - 11:00 PM



Does anyone know if you could slip a couple of Volvo BW axles into a skyline housing to save redrilling the stud pattern?



volvo axles are 27 spline, totally different size too.


I was under the impression they were 28 spline Posted Image
Bugger...


even though, they are still a pretty strong diff for what they are.
i would even recomend it in an early holden with leaf springs as they are the right width, but it would have to have an lsd or a CIG locker as the planetry gears are incredibly weak and the pin that goes through the middle also.

#129 Heath

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Posted 01 June 2010 - 01:02 PM

What about the depth & shape of the spline grooves, axle O.D., axle end details? Bearing surface diameter, width & axial location? oil seal surface etc. I would suggest there is more to it than how many splines there are on the axle.

Out of interest... can you get full spools for Volvo diffs?

#130 TerrA LX

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Posted 01 June 2010 - 01:35 PM

Out of interest... can you get full spools for Volvo diffs?


You can get a full spool made for any diff, including a bango.

Diff strength needs to be looked at how well the housing can hold the hemisphere and if running most other than a full spool then how strong the pinion is.

#131 rodomo

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Posted 01 June 2010 - 04:47 PM

Did I read on here that the locally built Volvo diffs were Dana?

#132 greens nice

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Posted 01 June 2010 - 05:20 PM

yes, i think theyre called a dana 30
i have a complete volvo diff with welded centre, if anyone wants it, come get it otherwise it will be heading to sims. does have half a tooth chipped off the crownwheel because the pin fell out, dug into the housing etc metal everywhere, but it still works haha.


#133 _youngy_11_

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Posted 17 June 2010 - 04:35 PM

What options do I have if I want to shorten my R31 diff.

Reason being, the only way to fit 17x8 Streeter wheels with the offsets available is to shorten the diff 1" or 3/4" either side.

A local diff place said I would have to go for billet axels at $500 a pop, which im not very keen on doing.

Thanks

#134 ls2lxhatch

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Posted 17 June 2010 - 05:10 PM

How much do you need to cut off each side?

Sometimes there is enough extra spline on the factory axle.

#135 TerrA LX

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Posted 17 June 2010 - 05:25 PM

What options do I have if I want to shorten my R31 diff.



Thanks


Pump the guards.

Have you shopped around on axle prices?
Just cause he shortens your diff does not mean you have to buy axles from him.

#136 Guns n roses

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Posted 17 June 2010 - 07:48 PM

actually made the enquire today and the diff place said you would have to shorten the axl bout 3 inchs before you can re spline it.so yah he said new axls at around $400 each.

#137 76lxhatch

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Posted 17 June 2010 - 08:35 PM

You can trim up to maybe 10mm off the end of most BW axles and still have the original spline fully engaged with suitable clearance in the side gears, so you could narrow the housing by the same without having to replace axles. Its possible to cut the spline further along the axle (it will be a shallow cut though) if you want to gain a little more, but then you're reducing the spline contact.

#138 _youngy_11_

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Posted 18 June 2010 - 08:41 AM

Well the current wheels are 17x7 with 4.5" back spacing. So if I was to fit 17x8s I would need 5.5" backspacing. Make sense?

Streeters only come in 17x8 with 4.5" backspacing but they can make it 4.75" backspacing by machining off 1/4" from the mounting face.

I would need to shorten the diff(move the mounting face in) 3/4" or 19mm to retain the outter edge of the wheel in the same position.

As for pumping the guards it would help a little but im pretty much on the limit on the outter edge even with rolled guards.

Edited by youngy_11, 18 June 2010 - 08:42 AM.

#139 _evil UC hatch_

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Posted 19 June 2010 - 02:00 PM

there is approx 50-55mm difference in length between the long and short axles in these R31 rear ends, so if you shorten the long side of the housing and use short axles on both sides you will then have a diff 25-27mm shorter each side and the center will be in the center of the housing instead of being offset, if you go down this path just watch you uni joint angles, as you should in any diff conversion anyway

#140 _youngy_11_

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Posted 19 June 2010 - 02:12 PM

Thanks Jason. This would have been the easiest method to take when I had the diff fitted a few years ago. But in doing what you have said, I would need to have all the mounts moved aswell, it would be cheaper and better to go for the billet axels and $300ish to shorten both ends.

#141 _evil UC hatch_

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Posted 19 June 2010 - 02:17 PM

or you could sell the Diff to help fund building up another one, they seem to be popular now so shouldnt be too hard

#142 _rorym_

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Posted 20 June 2010 - 12:05 AM

You will have to change the shock mounts if you shorten the diff/axles too much...its close with a 5" backspace...then you will start to look at touching the inner guard/floor lip if you take the backspace further..
R

#143 _youngy_11_

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Posted 21 June 2010 - 07:23 PM

The shocks mounts have already been moved in, as far as they can go.

#144 _rorym_

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Posted 21 June 2010 - 09:50 PM

You have a problem then.
R

#145 _youngy_11_

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Posted 22 June 2010 - 09:50 AM

The closest inner section that the wheel will hit is the chassi rail, the rear of the tyre will hit here first. I have more than an inch clearance at the moment, so if I shorten each side by 1" everything will still clear. There is also enough clearance between caliper and shock.

I may be looking at this the wrong way.

To shorten the diff, they would have to chop an inch off the diff tube near the hub end? Not the centre end?

#146 Guns n roses

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Posted 23 June 2010 - 09:13 PM

do you already run the skyline discs??is there any other brakes that would bring it in more or is it pretty much all discs are the same and there just narrower than drums?

#147 _youngy_11_

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Posted 28 June 2010 - 08:36 AM

Yeah I run the sykline discs. I don't think other discs would bring the wheel in much, the skyline ones are preety thin.

#148 _freddy_

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Posted 28 June 2010 - 09:08 PM

im goin to do this diff conversion on my uc sedan very soon just want to clarify afew things,

do you need to shorten the diff housein and axles?

can you weld the housein with a mig/tig welder?

are these diffs strong enough to handle a 355 Holden Manuel, i also like to do skids?

sorry if its been already said.

thanks matthew

#149 76lxhatch

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Posted 29 June 2010 - 07:41 AM

No shortening required as the diff is only 20mm wider overall (assuming that suits with your intended wheels), including the disc brakes.

Plenty strong enough if in good condition. The LSD centres however are not particularly long lived with big tyres and/or burnouts, if you have lots of money apparently you can get Kaaz LSD centres, or you may want to look into a Lokka: http://www.4wdsystem...index.php?id=29

The worst part of the welding is that the centre of the housing is reasonably thick cast steel and part of the top arm mounts need to be welded to this. I don't know enough to make a recommendation on methodology but I do know it can be done effectively.

#150 _freddy_

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Posted 29 June 2010 - 09:12 AM

ok thanks for that iv got an uncle that is pretty good with all types of metal work so ill set it up and tack the mounts where i need them then ill get him to finish them of, thanks matthew
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