Thread: 3.54:1 Range Rover diffs into S2A?

Originally Posted by Rocket88

Hi JDNSW, I assume you mean the "problem with this solution is that in a 109...."

If you've got a few minutes, I'm keen to chat to you about chassis (what is the plural?)

Thanks,

joe

Maybe I could have worded that better.

The original question mentioned an 88, the Stage 1 was only made as a 109, so all Stage 1 diffs are from a 109.

The two chasses differ as follows:-

The 88 and 109 refer to the wheelbase in inches. In other words, the 88 is short wheelbase and the 109 is the long wheelbase. These wheelbases replaced 86 and 107 during Series 1 production when the engine bay was lengthened in 1956 for the diesel, and wheelbases were unchanged until the end of Series production.

The 109 chassis is deeper than the 88 as well as longer, but the key difference when considering axles is that the 88 has the rear springs under the chassis rails where the 109 has them further out, alongside the chassis rails.

Hope this helps.

Thanks JDNSW, very helpful in raising my understanding of the differences between swb and lwb chassis, etc.

Changing diff centres also raises the offroad gearing, a better option might be a high ratio transfer box conversion.

I was lucky as a vehicle I purchased came with one fitted.
Ashcroft in the UK supply the parts but you need someone to do the machining to complete the modification.

They only list the complete conversion here (and you have to send them your transfer case) but I'm sure they will also supply just the parts.
I also notice that it's not available till mid year.
Ashcroft Transmissions

There are some pictures in this thread (a lot are missing thanks to Photobucket).
Isuzu C240 powered Series 3

Mine has a N/A Isuzu 2.4 fitted. Pulls away OK and will keep up with the traffic on the freeway (just a bit slower getting up to top speed !).
Only downside is you really need to drop into 3rd below 60kph.


Colin

Originally Posted by Rocket88

Hi All,

I know there is a thread (or a few!) about this, but I can't find the answer I'm looking for. I understand why the diff ratio change is desirable, and have picked up on the possibility of mixing/matching gearboxes/TCs to get the best combinations of gearbox & TC ratios for road driving and low speed bush work.

If I wanted to put 3.54:1 diffs in my S2A 88", would I just change the diff centres or do the early Range Rover diffs just "bolt in"? If they bolt in with few mods, it would provide a better braking solution as well I guess.

Any / all responses appreciated. This is a bit of navel contemplation at present as I try to work out my best options with "Jonesy" my 71 SWB diesel.

Thanks,

joe

Joel,
an overdrive might be the best option for your vehicle as i assume when you say it's a diesel you mean a Land Rover 2.25 diesel engine.
At least with an overdrive you can disengage it and go back to standard gearing if your towing or in hilly country.
The high speed transfer case or higher ratio diff options won't allow you the flexibility of an overdrive.
I have 3.54 diffs in my S3 88 and i prefer them as they slow the complete drive train down by, so less noise, less wear, and far less oil getting thrown out however i have an engine upgrade.

Cheers, Mick.

For what it is worth, my view is that the standard gearing is quite suitable for the 2.25 engines, either petrol or diesel, especially when fitted with 7.50 tyres. There may be an argument for higher gearing if using smaller diameter tyres on an 88. (I have an overdrive on my 109 petrol, and very rarely use it)

These engines are quite happy at high rpm, and provided they are properly maintained, it will not hurt them. Above 60kph, in my experience, most noise in a Series Landrover with the holes in the firewall and floor properly blocked is road and wind noise.

From memory the power output of the Isuzu C240 I have in my Series III was close to that of the Land Rover diesel.
I was 'warned' that the gearing would be way too high with the high ratio transfer box but this isn't the case.

If you can afford/justify a new overdrive then that could be the way to go. Finding a good Fairey or Toro overdrive could be difficult and reconditioning is expensive if parts are badly worn.

Maybe get it back on the road and then make a decision.


Colin

Originally Posted by gromit

From memory the power output of the Isuzu C240 I have in my Series III was close to that of the Land Rover diesel.
I was 'warned' that the gearing would be way too high with the high ratio transfer box but this isn't the case.

If you can afford/justify a new overdrive then that could be the way to go. Finding a good Fairey or Toro overdrive could be difficult and reconditioning is expensive if parts are badly worn.

Maybe get it back on the road and then make a decision.


Colin

Good advice, thanks Colin.

Originally Posted by gromit

If you can afford/justify a new overdrive then that could be the way to go. Finding a good Fairey or Toro overdrive could be difficult and reconditioning is expensive if parts are badly worn.




Colin

Colin, is the Canadian Roamerdrive an option. I know nothing about their reliability etc. They seem to be available in Sydney.