Rover V8 to MT75 Adaptor – part 4

This is an MT75 4×4 gearbox from a 2.0lt turbo Sierra Sapphire Cosworth. The bell-housing bolt pattern is much smaller than that of the Rover V8.

Unfortunately, the bell-housing is not removable, so I am cutting it off with a hacksaw. It may seem a little Low-Tech and indeed there is nothing Hi-Tech about my removal methods, but this has been planned and modelled in 3D CAD before hand. See here.

Modified MT75 Bell-housing

5 minutes later, the bell-housing has been removed.

The hard bit is getting the rare BW35 automatic bell-housing from a P5 automatic Rover V8 to fit.

Rover V8 BW35 Automatic Bellhousing

Visually, this bell-housing seems perfect for my needs, but how does it mate up?

Well first, I need to cut a hole for the clutch release lever. In my haste, I didn’t check the CAD and cut the hole by eye. – I’ll never learn. (I was a whole 8mm out! ) – at least it’s not disastrous.

MT75 to Rover V8 adaptor

So does it fit? I really needed to know!

Modified MT75 to Rover V8

There will still need to be some careful measuring, adjustment, centring and levelling but it actually not too bad at all. Plus, I’m going to make a better stab at the clutch lever hole.

For more images see the Rover V8 to MT75 Gallery here.

As you can see, it’s not a definitive ‘How to fit a MT75 to a Rover V8’ type of article, but as far as I know this is one of the first and probably my only ever attempt at this modification. I’ve certainly never seen another Kit Car with this done. I don’t know what the Dax Quadra had, but maybe they did something similar???

Now I know this is a viable modification, I’ll get the gearbox scrubbed up. I’ll stick it into the boot and get the brother in law to spot weld it with his TIG welder. We’ll get it spot on level and central, once we are happy, I take it to a professional aluminium welding specialist to finish the job. To finish the job, I’ll get a local gearbox specialist to give the whole gearbox the once over. The guy I bought this gearbox from, said it was ‘problem free’, but I never trust these descriptions much at all – It was only £35.

For related articles see:

Once this operation is completed, I’ll be able to get the Rover V8 and gearbox positioned in the chassis. For piece of mind I need to do this before I weld on the mounts for the gearbox, Sierra front differential, steering rack etc. 3D CAD is great and so far, its been spot on, but the infant mechanic in me, needs to play with real building bricks – ‘Kit Car Building for dummies’  style.