Topic

SD1 V8 certainly but an LT77?
Mind you if you found the correct parts you could make it four wheel drive & have low range.
I’m not sure what gearbox other Rover V8 adopters used, like TVR, maybe it was the 77 & I’ve not had impressive experiences with them. They’re a bit heavy or is that a misconception, my back implied it was !
I’d be interested to know.
M

LT77s are what was normally fitted to various BL cars, such as the Truimph TR7, TR8, Rover SD1 etc. they weren’t the strongest gearbag, indeed a bit marginal when behind a RV8, due to the distance between the shafts being only 77mm
It’s a basic rule of thumb the the more space between the shaft allows for stronger gears and therefore the gearbag is capable of handling more torque. As I said it’s just a basic rule of thumb, there are course exceptions to the rule, but in this case I believe that the rule of thumb applies.
If the RV8 in question isn’t too highly tuned the gearbox should handle it well enough, especially as the MGB isn’t a very heavy car.
As I’ve mentioned previously I intend to build a large capacity engine based on the Leyland P76 4.4 litre version of the RV8, I expect to get a capacity of just below @ 6 litres.
But the problem I have is the monster RV8 I intend to build will chew up and spit out a LT77.
When I do the initial conversion I’ll use a RV8 in a normal state of tune, and run a LT77 this is to amuse the registration authorities here, as the closer it is to something the factory built the less it will disturb their pointy heads.
The I’ll start building the monster engine once I’ve got the car sorted but amongst the changes required I’ll probably have to fit a Tremec 5 speed as they’re quite capable of handling the torque and there is a suitable bell housing available.
I would prefer a Tremec 6 speed but there is no suitable bell housing available at this stage and it’s doubtful there ever will be unless I can be arsed making one.

The Jaguar engine is a tight fit but hopefully it will be worth it, the RX8 gearbox is a heavy beast (50kgs same as a MGB OD gearbox) but it sits low down in the middle of the car. Here’s a very interesting swap; https://rlw7w.uk/about/
It’s a Vauxhall Omega engine that it’s very easily. Most MGB V8’s in the USA use the T5 gearbox as did TVR. If you decide to go with a T5 from a TVR then you need a tail shaft housing from a Sierra Cosworth to get the gear-lever in the correct position. I actually had every part to do a Rover V8 swap but some lowlife stole the engine, gearbox sump flywheel etc. Then life got in the way for ten years or so. Then I started to think about it again, you should know by now that I like a challenge. On another MG forum someone said that you couldn’t do a 200bhp MGB for less than $10,000, Isaid that I could do it for 5,000. The challenge was which engine, I came across a few Locosts with the Jaguar engine and RX8 gearboxes and the die was cast. I bought a 81000 mile SType for £500 and immediately stripped it, I got over £1100 for the catalytic converters, gearbox, a few other parts plus the scrap. The car had been serviced every year from 2001 until 2016 by Grange Jaguar then by a local garage. I have made mistakes along the way but generally have come out okay. I will be seventy on Sunday so another weekend wit nothing being done. I would like to have the four link rear suspension fully built by Xmas, so that I can have a 3.3 lsd fitted. Then the engine gearbox installation during January. We are then of to Oz and NZ for two months, so hopefully I can have the body shell media blasted prior to painting during the summer. Probably all wishful thinking but no harm in hoping.

I didn’t pay much attention to what went on under my SD1’s, at the time I had a family to bring up & a busy business to run.
Leisure time was spent afloat & not grubbing around under a car. It was with the 77 in a Land Rover that was my first introduction & I have to say I’ve not been lucky with any iteration of their cogboxes. That’s why my lad & I can have one out on on the bench before our brews are cold (figure of speech!).
I didn’t have a moments problem with them whilst under the SD1’s, just unfortunate latterly.
So thank you chaps for that bit of education.
M

The Landies are heavier and will cause more load on the gearbox, therefore it would explain how the LT77 was more troublesome in that application.
The Landies of course run a different clutch and as such a different bell housing and of course they’ve got the transfer case bolted to the rear in place of the extension housing, these factors may also have some bearing on the reliability of the LT77 as fitted to the Landie

It’s all well & good telling me these things now when I’ve waved goodbye to most of them, I needed that information twenty years ago.
Of course in retrospect the little black lump between the bell housing & 4WD clutter should have been familiar, but when you’re on your back very near an expanding puddle, doing a gearbox recognition quiz is but a distance thought.
I might use this information sometime in the future but it’ll be in the capacity of consultant, not participant.
Thanks.
I’m waiting for the opportune moment to upset Cobber’s equilibrium by wishing him a happy Christmas.
I await a caustic retort.
M

BAH HUMBUG!

That’s just the reaction expected.
Have a great Christmas Cobb’s, if you lived closer I’d come & sing carols at your door & you could throw solid objects & profanities at me.
M