Thread: Info on P6 Diffs, and ratios

In the absence of anybody else: I was bored and had a look at P5, P6 & SD1 diffs. Whilst P5 & SD1 appear to be Salisbury designs, the P6 is a DeDion and has a different nose to a Salisbury. If you wanted to experiment with a sal, you have a choice of 4.7:1 from a 70's Series 3 Landrover or 3.5:1 from a V8 80's County. With the "Rover ' diff ( P4, series 1/2 LR, front series 3 and 90's Discos) you again have the choice of 4.7, ( 4 & 6 cyl ) 3.5 (turbo diesel, V8's) and aftermarket 4.11 ( modified v8's). Whilst the P6 is a Rover design, sometimes the LR engineers purposely make equipment that is proprietary - which means that using a R & P from a LR may not work. But good luck anyway - I could be wrong and someone could come up with a solution for you.

Kedron Rovertech in Brisbane work on the old rovers, they might be able to help with parts etc

As mentioned, P6 is a De Dion. Totally different diff to any live axle car - inboard discs etc.

One solution to think about would be to shoehorn in a Jag XJ6 / XJ12 diff - same design layout, but I daresay twice as strong. And better ratios too. Rear discs might be bigger than the front though...

One snag would be that the P6 locates the wheels through solid driveshafts, and has a panhard rod on the diff that (hopefully) doesn't move. Jag locates through a subframe, so you'd need to copy the rod & look into whether the bearings would cope with lateral load.

Aston Martin used this diff as well in the 70s & 80s. Only difference was they used a bigger cover to get better oil capacity & cooling.

Regards
Max P

Hi Chad,

The were only two diff ratios available for the P6, 3.54 : 1 which was fitted to the 4 cylinder cars, and 3.08 : 1 which appeared in all the V8 powered cars. The weak link with the diff is in the drive shafts (not the half shafts) that support the discs and onto which the half shafts bolt. The drive shafts are also no longer available and have been that way for some years.

Out of interest if you don't mind, is your Borg Warner transmission the 35 or 65?

This P6 has had the Jaguar diff assembly fitted and as you can see, there is considerable work involved in doing so.

The Classic Rover Forum • View topic - P6 muscle car project

Ron.

Originally Posted by Tusker

As mentioned, P6 is a De Dion. Totally different diff to any live axle car - inboard discs etc.

One solution to think about would be to shoehorn in a Jag XJ6 / XJ12 diff - same design layout, but I daresay twice as strong. And better ratios too. Rear discs might be bigger than the front though...

One snag would be that the P6 locates the wheels through solid driveshafts, and has a panhard rod on the diff that (hopefully) doesn't move. Jag locates through a subframe, so you'd need to copy the rod & look into whether the bearings would cope with lateral load.

Aston Martin used this diff as well in the 70s & 80s. Only difference was they used a bigger cover to get better oil capacity & cooling.

Regards
Max P

The Jag diff is a Salisbury 4HU and I think that's a UK version of the Dana 44, much like the Salisbury 8HA in the rear of a 110 is a reworked Dana 60.

Not sure what CWP was used in the P6 but I'm googling ATM

Originally Posted by Chad

Just got my Rover p6 Twin Turbo V8 going, and need some higher diff gears, to get it up in the rpm earlier. I

Wouldn't that be lower that you need. i.e., higher numbers = lower ratio?

Yeah MAte, Higher NUMBER, lower Ratio, sorry,

Thanks for all the info guys, will work out the best solution, seems like the Jag, may be the way to go.

Chad

Originally Posted by Chad

Yeah MAte, Higher NUMBER, lower Ratio, sorry,

Thanks for all the info guys, will work out the best solution, seems like the Jag, may be the way to go.

Chad

Make sure you get a 4 spider gear LSD, I blew 2, open wheelers up in no time