Isn't the bell housing on the Mazda box integral with the main casing?
From the ones I've seen I'd say you are correct, integral bell-housing. May be possible to create an adaptor though. Wouldn't be cheap I'd imagine.
If you could get hole pattern data for the engine's rear end and the bell-housing it would be a starting point.
Other way would be to hack off the Mazda's BH and graft on a Rover BH.
Re: Bellhousing for Mazda mx5 box to Rover V8
Posted: Sun Aug 06, 2023 8:35 am
by ratwing
Rpi do a kit with what looks like a bolt on bellhousing so I just assumed they were separate (maybe they modify the front of the box?) However, they wouldn't just sell one on its own. On reflection I think the cost is going to put a stop to this idea.
Re: Bellhousing for Mazda mx5 box to Rover V8
Posted: Mon Aug 07, 2023 12:23 pm
by GDCobra
Just had a look at the RPi offering. Looks like they sell it as a conversion (at £4.6k) which seems to be specific to the MGB. May not be too bad if you have a top spec' MGB worth plenty of money but it's a fair chunk of change otherwise. From the photo's it looks like the front casing of the 'box is machined to suit the RV8 bell housing. I wonder it this is the MK 1,2,3 or 4 'box.
Not sure how good the Mazda 5 speed is, I've had two MX-5s, both with 6 speed boxes and I don't think they're as slick as many people make out although I have heard the 5 speed is a better change.
I'd also question the strength of a 'box from a car with, maybe, 160BhP and limited torque to go behind a RV8 with, hopefully, a good dollop more power and torque.
Re: Bellhousing for Mazda mx5 box to Rover V8
Posted: Mon Aug 07, 2023 5:33 pm
by stevieturbo
Why the Mazda box ?
Doesn't seem like an ideal or common swap ?
Surely a BMW box would be more common ? Or Toyota, or something
I think Jim at www.jrv8.co.uk was doing some Getrag conversion stuff a while back.
No idea who he is, or what box, it just popped up in a search
The RPi kit is not cheap but does include all the parts necessary including clutch, throw-out bearing and one or two other bits and pieces for the MGB, it's also a brand new box (apparently). Having said that I've had one or two sub optimal dealings with RPI in the past and I find their videos make me nauseous so I don't have any dealings with them these days.
The Mazda 5-speed box is light and apparently strong enough for a 3.5 Rover but the bellhousing problem makes it a non starter now. The BMW box looks big and heavy, don't know about the Toyota box but both need a bellhousing at significant cost (ie too expensive)
Re: Bellhousing for Mazda mx5 box to Rover V8
Posted: Fri Aug 11, 2023 1:29 pm
by stevieturbo
What are you trying to achieve ?
What is wrong with a regular LT box etc ? or other more common options ?
What is wrong with a regular LT box etc ? or other more common options ?
LT77s are very thin on the ground these days and what are around probably need rebuild and I don't think parts are plentiful.
R380s are newer and (apparently) inherently stronger but not many 2WD versions around as not too many RWD cars created in those days.
Reminds me, I have an LT in my garage which I swapped out for my R380, need to get that up for sale along with several other parts still in my garage.
T5 seems to be the most obvious choice and there must be bell housings around to fit them as some cars used them with RV8s, TVR for instance.
Probably not cheap though.
I'd have thought the easiest way to adapt any 'box to the RV* would be to cut off the front end of the Rover bell housing and the front of the donor bell housing and splice together. Notice I said "easiest" not "easy"!
If I were doing that I'd choose one with a detachable bell-housing though I think.
I'd have thought the easiest way to adapt any 'box to the RV* would be to cut off the front end of the Rover bell housing and the front of the donor bell housing and splice together. Notice I said "easiest" not "easy"!
If I were doing that I'd choose one with a detachable bell-housing though I think.
That approach is fairly commonplace, although usually beyond most DIYers. But certainly is doable.
If you have a lathe, mill etc and can weld....all the easier. Without any of these....not so easy.
Reality.....just accept the kits cost money and stump up.
This doesn't mention what engine, or whether vat is included
Exchange rate was better then, and boxes were readily available. Not so much either now. Any conversion you choose, should be a box that is readily available, just to ensure an ability to service it in the future if needed.
Considering the nature of the new bellhousing required on the MX5 kits....the prices don't seem unreasonable as it forms a chunk of the gearbox itself. That's a large new casting with a lot of machining
Re: Bellhousing for Mazda mx5 box to Rover V8
Posted: Fri Aug 11, 2023 8:01 pm
by stevieturbo
New bellhousing for a Tremec, and new boxes are available....at a price of course.
One route to a Nissan CD009 swap, again, their approach might allow you to adapt an existing bellhousing to their adapter. But as these boxes can be popular with drifters, may be more pricey
Just had a look at the RPi offering. Looks like they sell it as a conversion (at £4.6k) which seems to be specific to the MGB. May not be too bad if you have a top spec' MGB worth plenty of money but it's a fair chunk of change otherwise. From the photo's it looks like the front casing of the 'box is machined to suit the RV8 bell housing. I wonder it this is the MK 1,2,3 or 4 'box.
Not sure how good the Mazda 5 speed is, I've had two MX-5s, both with 6 speed boxes and I don't think they're as slick as many people make out although I have heard the 5 speed is a better change.
I'd also question the strength of a 'box from a car with, maybe, 160BhP and limited torque to go behind a RV8 with, hopefully, a good dollop more power and torque.