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MG MGB GT V8 Factory Originals Technical - Gearbox Choice !!
Right I,ve bitten the bullet and aquired a nice 3.9 V8 rover engine for my B.But what gearbox to put behind it? ( Bear in mind I live Australia ).Lt 77 and R 380 are like hens teeth down here,and the toyota supra box option will cost 2400 dollars from Dellow (the only people I've found to supply all the bits required to make the conversion).About 800 dollars cheeper if i get the box of ebay but still lots of $$$.
So I read that in the UK they use the Borg & Warner T5 box.Is that available here? If so in what car? In the US they have the Camero to steel a good box from.
Do we in Australia have a cheap and easily obtainable gearbox ?
I am not certain if someone like D&D makes a conversion kit using the Ford Mustang T5, but if so, you could get the right bellhousing for one of those otherwise if your going to use the Camaro, you will need a 1983-1992 Camaro or Firebird V8 T5.
|BMC Brian McCullough|
|What box does the Holden use? I thought it might be the GM version of the T5 same as the Camaro and Firebird. I know the new GTO that we got here a couple of years ago was just a rebadged Holden chassis, but I think these used the T85 six speed box. Earlier models should have the T5 I'd think.|
|Another option worth considering: I know most are going to scoff at this as a matter of course, but have you considered a modern automatic? It may be a practical choice if set up properly. A 4 speed OD auto with lock-up converter is in effect a 5 speed transmission. Add to that a fully manual valve body (reverse pattern) and a ratchet shifter and you have the functional equivalent of a 5 speed manual except for the clutch. Lock-up clutch control can be manual, auto, or both, and if fully manual with a button or toggle switch, it will stay engaged even at low engine speeds, as I've heard stories where guys killed the engine by hitting the brakes hard because they neglected to put a braking switch in the circuit. I wouldn't use it for starting out though as engagement would be abrupt and it might wear out. The right selection of torque converter lock-up speed to match your driving style, and there's very little difference. Shifts are where and when you want them and it stays in the gear you select, plus it shifts faster than you could ever do manually. In short, kind of an intermediate step between the manual box and the Ferrari's paddle shifters. Due to the lightness of the car I'd tend to be conservative on shift firmness.|
There obviously must be a common tranny to fit the Rover V8, the question is one of size and will it fit in the tunnel without modification. Here in the states I expect a GM 200-4r will work but I don't know of anyone who has tried it yet. But here, that transmission will not fit the BOP/R pattern, though it will fit most later engines in the GM line. Should you choose that route we'd obviously like to hear of your results, as well as what tranny you used.
Here are the paddle shifters for that set up.
Jim I love the idea,its different and cutting the tunnel well, she may just have to give a little.
I just need to find one to match,jap,GM or a Ford!!
(If somewhat pricey.) Knew it was just a matter of time. Of course, I have no idea if I'd like such a thing. And for less than that I'd expect I could hook a couple of solenoids to a ratchet shifter and have something quite similar. But well done! It'd be interesting to see what other sort of info they have on it.
|Warren, the Toyota Celica 5 speed box works just as well as the Supra version & costs a lot less. No matter which manual box you use, it's going to cost some. There's clutch parts, flywheel, bellhousing , plumbing to take into consideration. To keep costs down ,you'll have to use an auto box out of a V8 Rover, Range Rover or Landrover. I have a rdstr with a BW65 auto. It's a great car for city driving & highway cruising & if I want a bit more oomph, I use the selector manually. With a 5 speed behind the Rover engine , you'll find that you don't change gear very often anyway. My GT has a Celica box & once on the move ,I only seem to change from 5th to 3rd & back again until I come to a complete stop.I very rarely ever use 4th. Barrie E|
You don't need to buy all Dellows gear. In fact I bought his slave and spring plate, but didn't use them. Plate heavier than it need be and slave too small.
You need the bell housing, folk, release bearing and spigot bush which will run you around $600.
You can set up your own clutch. Since you are going to have to have a range rover flywheel machined about half an inch thinner you are free to choose choose whatever clutch spring plate you like. For a slave cylinder you need one thats very close to one inch and that has the right hose thread. The supra one (3/4") is too small anyway. I used rover one. There is a holden one availiable that might be better.
You can check around the various wreckers for a supra gear box. I was quoted $300 for one. You might be able to get one with the end of the tail shaft attached (they often just cut the boxes out in japan)Idealy you should get the 21 inch (front of gear box to gear lever). The W58 is best, W55 next. Barrie is correct about the Celica. If you hunt throught the archives there is a whole lot there about which model car had what.
Down the bottom of this link are some gear boxes. Be aware that their after sales service isn't the best.
I installed the 700R4 transmission kit from D&D Fabrications three years ago and it works like a champ with my slightly modified Rover 3.5! (500 cfm Edelbrock, Crower cam, pertronix ignition, HD oil pump, RV8 headers and dual exhausts. Also used the D&D V8 radiator, extended the length of the core, and used a hayden trans cooler mounted on the lower part of the radiator in back of the valance).
The kit comes complete with virtually everything necessary for the conversion: tranny,cross member, driveshaft, speedo drive, mounts, adapters, flywheel, torque converter, lockup module, etc.
Only two things gave me a problem- I ended up using a B&M cable shifter rather than the Lokar shifter supplied. And I ended up relieving the tunnel for more clearance than the instructions specified. It is a very tight fit...Another minor annoyance is that the speedo calibration is a bit off, using the gear and drive supplied in the kit.
Driveability is excellent, even with the stock 3.9 ratio MGB rear end. First gear is a bit low, but the overdrive makes up for it at the high end. From 55-80 in overdrive is like a rocket!
Overall, I am very pleased with my conversion!
Please email me if you have questions.
|Sounds good Dave, the 1st gear ratio on the 200-4r isn't quite as low as the one in the 700r4 (which is something like 3.10 or 3.20, the lowest available in an OEM automatic) and overall the 200-4r is smaller so it may go in without beating. Something I expect to find out perhaps next winter. It has proven to be plenty strong as well, racers are using them behind big block engines in some cases. I would be interested in the details of your shifter selection and what valve body you used, and I would think the details would be relevant to this thread.|
But Warren needs a Rover or Land Rover automatic, and I'm not sure of the similarities. I expect there is a good OD auto available though as they really haven't lagged behind in development work as far as I can see. Assuming there is one, it should bolt right up. Chances are pretty good his engine originally had one behind it.
I used a B&M Console Quicksilver Shifter designed to work with a 700R4 (Camaro). I built a steel well into the top of the tunnel to protect the shifter. Routing the cable and hooking it up is a tight fit. It looks very good on top of the stock '79 MGB console, almost like factory. OBTW, the cable that came with the shifter kit only lasted about a year. B&M supplied a replacement that was much more heavy-duty than the one originally supplied).
I transmission that D&D supplied with the transmission without any further modification. It wouldn't surprise me if it had a modified valve body, because it has a very tight shift between 1st and second (chirps the tires without provocation upon upshift).
|I use a 700R4 in my MGBGT with a 3.1 liter six. I have a switch that locks up the converter on 2nd, 3rd and 4th. It will not lock up in first. Jim drove the car at Townsend this past year.|
The 200-4R is a good trans. Ihave one in my 85 jag XJ6 with a 5.7 liter. I have used this set up since 1996. I works very well. The converter in my car only locks up in 4th. It has proven very econonical to use.
|I did a trial fit with the 200R in my GT, and it looked like no cutting or banging. Finally decided to use a T-5, but not sure that the 200R would not have been a better choice.|
The T5 is used in Commodores from VN - VR (V8 version) and VN - VX (v6 version). Should be easy to find one at the wreckers. Not sure about bellousings etc.
Contact MG Workshops in Melbourne as I know they used the T5 in a few racing MGs.
I think you'll find the perhaps the T5 is the ultimate for strength but the Toyota box is easiest and chepaest
This thread was discussed between 09/02/2007 and 13/02/2007
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