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 - Rover V8 with original B tranny and rear axle

Any of you seen this combo? Comments on it's durability and practialbility? Sounds a bit scary to me but I'd like to know what you V8 guys say! Thanks!
gerry masterman

This has to be the least expensive way to build a V8 conversion. You avoid the cost of a different transmission of course and pay for an adaptor, which is cheaper. Furthermore, there is no need to replace or modify the prop shaft or speedometer unless some change is done to the rear end and the speedometer cable is unchanged. There is no need to modify the transmission tunnel or shifter. Even the starter is retained from the four cylinder, which avoids changes to the wiring as a bonus. This brings up the first drawback however and that is that the starter mounting on the motor must be cut away. That’s something not easily remedied if the second drawback rears its ugly head. That second drawback is that the original transmission is not known to be able to cope with the extra torque of the V8.

Too bad the Costello transmission is not readily available. It bolts to the motor without an adaptor or a need to cut the starter flange. It fits without changes to the tunnel and uses the original prop shaft and speedometer cable and it is strong enough to handle the torque.
George Champion

With the stock 3.9 rear axle ratio, the V8 will have fantastic acceleration (in any gear) but will run out of breath very quickly. Top speed could actually be less than the 1800, as the V8 won't rev as high. Whether the components cope with the power depends on how much power the engine is developing, and how it's driven. The axle will probably be OK, but the gearbox could be marginal. I know of one such car over here that has survived several years.
Mike
Mike Howlett

Top overdrive gives 22.3 mph per 1000 rpm, so the V8 will make over 120 mph at 5500 rpm.

The real issue is the gear box and propshaft are at their limits at 140 bhp so OK with a mild V8 but an SD1 used in anger will break something - I've seen a propshaft twisted like a sweet wrapper from too much BHP........
Chris Betson

George,

The Costello transmission may became available from Tim Fenna at Frontline.

Paul
Paul

Gerry,
My first conversion was done using the DIY kit from england. I used an '80 SD! mtr. and MGB O/D transmission. I did the conversion in '94 and drove the car till 2001. I have since installed a '95 3.9 L Rover and SD1 5 spd.
Keith Childs

Keith, did you find high engine rpm at hiway speeds to be problem? I'assuming that you retained the stock rear axle ratio.
gerry masterman

Gerry,

Keith Childs

This thread was discussed between 15/05/2002 and 18/05/2002

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