Thread: Rover Diffs in a IIa SWB

Originally Posted by harry

I would just ditch the overdrive and fit rangie diffs,
oops, that is what I did!

and how did that affect drivability on and off road young harry?

Originally Posted by incisor

and how did that affect drivability on and off road young harry?

Sorry Jonno 1969, for the slight thread hijack.

the boss asked for an answer,

to answer Incisor's question, and for others,

re fitting 3.5 range rover diffs to a 2a shorty,

Initially it was far better than I thought it would be.
on normal tyres, 7.50x16 bar treads, the take off from the lights was noticeably better with us being able to run gear change intervals with modern road cars, it really got longer legs.
110 was easy to achieve without caning the engine.
I put the little car on 9.00x16 bar treads and noted that take offs needed a bit more care of the clutch, but recently found my clutch was wet with oil, so perhaps that wasn't a problem,
we will know more after I get it going again.
110 was still easy to achieve, but we do need a bit of patience to get past 90, drag on a brick like object takes some overcoming! But I have seen 130!

The beauty of this is that I can run modern highway speeds and not block traffic.

Hills are another story! it blatantly refuses to run up hills, choosing to make us walk if the gradient is too steep or too long, often back to 1st,
I have even grabbed low range, but once in low, we need 3rd or 4th gear, as 1 and 2 are unbearably slow.
In fact if we need to be in first gear high range, swapping to low range 4th is quite good, anything lower doesn't really cut it.

off road in low range with 9.00x16 tyres, you wouldn't notice any difference, it climbs over anything and is quite tractable in low first, you may have seen my videos of me taking it for a walk.

Back to Jonno 1969's thread,
and perhaps Inc, you could move this report somewhere to clear from Jonno's overdrive.

I saw this mod some time ago, or is this another one?
has it been satisfactory, or does the overdrive transfer oil to the transfer case?

pretty much as I thought it might go...

9.00x16 hey...

uncleho's busted lightweight has some diffs from a rover car

can not remember the ratio at the moment but it seemed to go well.

thanks for the info harry....

Many moons ago when I owned a 1966 S11A SWB I replaced the original diffs (still in the shed somewhere) with Rover 90 diffs. Direct bolt in replacement. From memory the std ratio was somewhere around 4.6 and the Rover 90 ratio was 4.3 or thereabouts. With my fully balanced 2 1/4 litre petrol engine with Perry headers it could hold 60 mph all day(on the flat and if you could stand the noise). The Rover 90 diffs saved around 200-300 rpm at 60 mph.

Deano

Noise, what noise, can't hear a thing.
i got tired of the gearbox crying, so am replacing it, which has grown into more than I wanted.
now have engine out for a look and replace some bits.
but the greatest noise is my rear diff, which is a bit noisy!
when I ran 7.50x16 bar treads, people on the street 600 yards ahead would turn around to see what's coming!

Drove an S3 shorty last night with 3.54 diffs in it. Engine was a healthy 186 Holden. Went very well and sat in 100 easily. It even had an overdrive on it which would drop the revs to 2,250 rpm at 100 when engaged. This vehicle can tow a small camper trailer and still sit on 100. Very good conversion if you have a bit more grunt than a standard 2.25. Didn't go into low range so no feedback on how it effects this.

After getting a high ratio transfer box on a project vehicle some time back this is another option that's worth considering. Not cheap though, especially if you don't have the facilities to do the machining locally.

Mine is behind a 2.4 N/A Isuzu and holds 100kph. Much below 60kph it needs to be dropped into 3rd but it accelerates OK as long as you keep the revs up a bit.

Isuzu C240 powered Series 3

From memory the offroad gearing is only raised by a few %.


Colin

Harry what brakes are you running?
Do you need to buckle the steering wheel when you want to pull it up with the extra inertia of those 9.00's?
Also I think the Rover car diffs are 4.1 ratio.

Cheers, Mick.