MG-Cars.info

Welcome to our Site for MG, Triumph and Austin-Healey Car Information.

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MGB GT V8 Factory Originals Technical - V8 Diff Ratio

I am currently fitting a Rover 3500 motor and a Toyota Cressida (Celica) 5 speed gearbox to my rubber bumper MGB.
I can't get a W58 box which has a top gear ratio of 0.78 in this country so I will have to make do with a W55 which has a ratio of 0.85. To compensate for this I would like to fit a Diff with a better ratio than the standard 3.9 say, 3.0. Does anyone know of a diff that would fit without too much modification?
Chris Barrow

Chris,

the easiest way is to use an axle out of a C, that comes with 3.3 or 3.09 ratio (take care, some had a 3.7 as the B with automatic gearbox). I used a 3.3 and a LT77 Rover 5 speed and it works very well.
A friend has bought a GTV8 last year, converted by Dave Wale and it came with a shortened version of the Rover SD1 axle with a 3.08 ratio.
I also heard from a Ford Capri 3.0 axle used unber a B V8 but have no further Information upon this.

May be some old Mitsubishi Chelica rear ends will work too?

Ralph
Ralph

I'm using a Ford/Currie 9 inch 31 spline axles and rear disks (Ford Explorer) with a small drum parking brake all supplied by Currie Enterprises. The housing is available in aluminum as well.

http://www.currieenterprises.com/

The Aussie dollar is pretty strong against the US dollar now so this may be a bargin you can't walk away from.
Michael S. Domanowski

Forgot to add my rear diff. ratio is a 3.00:1. I'm using a T5 World Class transmission with I believe a 0.78 final gear ratio and 15/50 series inch tires. At 80 mph I'm only turning 2650 rpm and I get over 25 mpg at that speed.
Michael S. Domanowski

Chris,
Aside from the diff fitted to the MG C most diffs for ratios in the 3.00 range are for larger vehicles so you may have very few options.

Perhaps a 4WD may be an alternative or maybe the 3.08 fitted to the Holden Commodore range imported to SA from Australia for a number of years in the mid 80's.

They all used a Borg Warner 3.08 diff and some had Limited Slip as well. Normally known as 4 pinion as opposed to the standard 2 pinion.

Pete.
Peter Thomas

Many thanks for all the information. I will have to look for something locally as the cost of importing anything into this country is prohibitive. Unfortunately MGC cars are like hen's teeth in South Africa, and I have yet to find a local engineering shop who do things like shortened axles. There are quite a number of old Rover SD1s around. I will see what I can find, and whether the expertise to shorten it is available. Thanks again to all for your input!
Chris Barrow

This thread was discussed between 09/11/2007 and 12/11/2007

MG MGB GT V8 Factory Originals Technical index

This thread is from the archives. Join the live MG MGB GT V8 Factory Originals Technical BBS now