RT142 Borg warner to R31 Diff (28 spline) conversion

[Mickp]

Hi there, In the coming week I am going to put an R31 diff in the RT142. I have sourced a big VL v8 LSD center for it and a complete diff, 28 spline skyline wagon,
The disc to disc length of the R31 wagon diff is 1460 mm,
I have the option of shortening the diff by cutting down the long side of the diff and using a spare axle the same length as the short side, to make an even diff.
The one thing I have been too lazy to do untill this point is measure the corona diff, I'm guessing that it will need shortening to fit the rona. If anyone has the measurement for a rona live axle I'd be much obliged,

Also if anyone thinks it would make a difference whether the diff center is at the center of the car (after shortening would make any difference or would it be all the same if I left a short one and a long one with the diff off center.

Although the volovo option is good, I have chosen this option for the cheapness of reaonable LSD centers and also the fact that there is no redrilling hubs as the skyline is already a 4 x 114.3 which takes alot of screwing around and a bit of cost out.

I will post pics as I go along. Any advice or suggestions people have with regards to ideas/changes would be appreciated.

All the best - Mick

[hemi twofifteen turbo]

it doesn't matter if the diff is not central, next time your behind and old F100 at the lights check out their tailshft angle, way off centre. If you think about it, it's just the same as having the tailshaft on the upward angle to the gearbox, just no as asthetically pleasing. Cheers.

[The Real Roadrunner]

the reason they run a short/long shaft in these is to keep the tailshaft in the centre of the car as the pinion is offset to the long side.
if you put 2 short axles in it will just offset the tailshaft. please check the tunnel b4 doing so as it may then clash with the tunnel during it movement up and down.
but other than that it should be all good.
cheers
linden

[lexsmaz]

I would try to keep it fairly central to the body, ( or in a similar setup to the factory RT142 style ) .... few reasons, 1 being fouling of the tailshaft on the trans tunnel especially if the car is lowered, 2 being if you are still runing a 2 piece tailshaft you could have some excessive wear & vibration issues on the rear short shaft ... Again not knowing the amount of offset on the skyline Diff you may be able to get away with it ... I have a RT142 diff in the garage so sometime tomorrow i will measure the overall width & let you know, it is a drum setup but i would imagine not much different width to a disc setup? maybe the thickness of the disc's only? ...

[Pube]

When I did my G-series conversion I found the Borg warner diff pinion to be 1 inch off centre to the drivers side and the Hilux diff to be 2 inches. I left the hilux 2 inches to one side and havent found any problems so far. You may find that the trans tunnel is also offset to the drivers side, thats what I found in my ra23 celica. From memory the corona borg warner diff is 1430 wide.

[Norbie]

If it is 1430mm I wouldn't bother shortening the diff, 15mm a side isn't anything to worry about - you can easily get wheels with an extra 15mm offset to compensate.

[Mickp]

Thanks for the input guys.

I will measure up the corona today to see, and if it is 1430 I cant shorten it as using a short side axle and a cut and shut as it will take 2 inches off it making it 1410 overall, and it's better to be a little too wide than a little too short.
Glad to hear 2 inches off the mark was fine in your RA23, I didn't realize the old borg warner in the rona's was 1 inch off center. From the looks of it all the mounts aren't in wildly different places so this shouldn't be too hard.

All the best - Mick

[lexsmaz]

Just measured up my RT142 drum rear end... Drum to drum measurements that i took were 1420mm total width, With the offset 40mm longer on passenger side .....
Spewing i gave away a spare 244 volvo diff i had when i sold my V8 volvo recently, wasnt really thinking, just happy to get rid of the bits lying around...
Wish i had stopped to think .. because i need to go the lsd route myself ....& will probably go the volvo route .... heard a while back the axles are meant to be bullet proof ....

[treads]

r31 diffs are 3.7 3.8 ratio depending on auto/manual you can get the pinoin of a nissan pintara which has 4.1 ratio but do not use the pintara diff although they look the same as the skyline pintara has 25 spline where the skyline is 28 spline

how much did u buy the v8 lsd centre for?