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MG MGB GT V8 Factory Originals Technical - 1976 MGB2000

I have owned my 1976 for eleven years now. The car has had a total ground up restoration with myself doing all the work. For the most part the experience has been enjoyable. However over the past three years I have barely taken the car out. I firmly believe this is do to the 1800- 4 speed powertrain setup. I have had the engine professionly rebuilt and I added weber carbs, but still this engine bothers me. For such a lack of performance, she sure knows how to burn gas and throw off heat. My solution right now is a Mazda B2000-5 speed transmission. The engine and tranny demmensions are almost exact. Also the truck differential is geared the same as the MGB so I could simply mate this drivetrain without any high or low RPM problems. My main goal if I do a conversion is to keep it simple and low in costs. My big qestion to anyone out there is do you know of a conversion using a B2000-5speed (from a Mazda pickup 84-86). If so please let me know about any pros and cons. p.s. I already bought a doner truck and the engine is presently being cleaned up. I decided to get a whole truck incase it would be nessary to transfer any of the eletronics, etc. Hope to hear from someone..
Mark Guier

I thought by '76 the export model MGBs had overdrive as standard, giving you a 5-speed tranny. Are you sure you have the correct gearbox ?
David Smith

Cheers, David

We should be so lucky! I don't know about Canada, but here in the States overdrive was an option on the MGB all the way through the end of production. I believe it was only installed on about 10% of all Bs imported to the US. That's why a used 4-synchro non-O/D gearbox sells for ~$100.00, but an O/D gearbox sells for ~$600.00.

This has always amazed me, here in this country of long straight Interstate highways. I once heard that the O/D option was limited to prevent competition with the Austin Healey 3000, but that doesn't explain why it did not become more prevalent after 1967.

Paul Kile
Paul Kile

Thanks Paul, I always get this wrong ! The 'models' section of this very site has an MGB specification which claims o/d was standard from 1975 - that may have been true for home market cars I suppose. If I knew who was responsible for content I'd drop them a mail asking for this to be clarified and straightened out....
David Smith

In reference to David Smith's qestion of weather or not I have over drive, no is the answer. As to why a car like this was ever sold in North America with out this feature being standard boggles my mind. Somebody must have been really trying to cut costs. My 76' MGB did not even come with anti sway bars, front or rear. Actually I have seen a few other 75'-76' s without the front anti sway bars so I know it was not a mistake with mine. I guess nobody had any comments about my proposed B2000 Mazda engine swap. Should I post somewhere else?
Mark Guier

Mark, if you do catch hold of someone with some experience in this particular swap, please share. It sounds like a good combination. I drove a B2000 for a couple of years as a company truck, it seems like it would make a good swap over the 1.8

good luck,
Sean Squires

Mark and Sean,
I owned a '87 Mazda B2200 (little extra displacement never hurt) with a 5 speed. Loved that truck, and drove it hard.
The RX 7 (first generation) rear tranny shift housing extension will swap with the '79 -83 B 2000 tranny if you need a little more length. You will need all of the internal shift levers (drive them out with a drift.) The second generation Rx 7 tranny can also accept that same rear housing. You can get .86 overdrive with a '86 RX 7 5 speed.
Good luck.

I have no personal knowledge of the Mazda unit but have an overview based on many conversions to MGs using alternative engines.

The standard US spec single carb B series is a slug, crude and low powered. The UK spec version is much better but still underpowered. With the corrrect balance of modification and more importantly correct setting up there is a massive amount of untapped potential in the B series. Over the years I have seen many conversions produce little extra, or even less power, than standard. So many more were very dissapointing until being set up properly at which time it is not unusual to see gains of 50% or more such was the poor state of tune to start with.

Against this backdrop is the prospect of removing the difficult to tune modified B series and replace this with a stock engine of larger displacment that produced so much more power than the standard B series. The only difficulty is fitting the unit so it can work properly, but then setting up is as per the makers service book - simple. This is why so many engine changes work so well compared to tuned original engines.

If this was the UK then I would have said go to a rolling road (chassis dyno) where the operators have experience of the engine and get the engine set up properly. Problems are quickly and simply identified during this process and this allows simple targetting of problem areas. The results are very effective and often completely transform a car.

If you haven't got the luxury of such equipment near you then the prospect of an engine change is a very attractivbe one since I see little prospect of you being able to achieve the modified B series 's full potential.

Roger Parker

Thanks for the above comments - Sean, Curtis and Roger. I myself drive a B2200 with 279000 Km and have had really good luck with it. The engine I am going to put in my MG is a B2000 because I found it to be a little more peppy in comparison to the B2200 without any load in the trucks. (I bought a running B2000 for the engine donner so I was able to compare the 2000 with the 2200 side by side. Plus the B2000 will give me more room between the top of the engine and the engine hood so according to my measurements, I should be able to retain the Mazda air filter. I know a lot of people here are doing some really neat conversions, and as Roger pointed out, I could probable get a lot more out of my B engine. However what I want is a relieble fuel effiecient conversion that does roast me with heat from the exhaust while sitting at a red light with mininal modifacation and low cost. So far I' ve paid 100 Canadian. My goal is to do this conversion for under 1000 canadian, with me doing the labour of course. Any more comments are greatly welcomed!
Mark guier

Correction for my last message- I want an engine that will NOT roast me with heat from the exhaust while sitting at a red light. I just find the B engine gives off a lot of heat. I have to be careful not to bump my tailpipe when getting something out of my trunk because if I have just been driving, the tailpipe is hot enough to burn me. The engine temp. is fine so I'm not running hot. On my B2200 I can pretty much put my bare hand on the tailpipe while the engine is running. I think it is important to have a engine that will not throw off a lot of heat in a car that should be driven on the hottest days of summer. Right now I find my favorite time of year to drive is in the fall when the wheather is cool and dry. The leaves help as well. Anyways, sorry for the missing NOT in previous thread. More comments please. M.G.
Mark Guier

mark, the conversion is a good idea. i have a '59 frogeye sprite with a 2.0L ford cortina engine with a 4 speed tranny. mazda commisioned ford to build their engines, so the b2000 engine is basically the same variant that i have under my hood. the only diffence is probably of fuel injection. the ford T5 (instead of the 4speeder that i have) transmission from the merkur xr4ti, that was available here in the states, fits right onto the 2.0L engine. i would suggest that you should look to find a ford variant of the engine because it will be cheaper, more rev happy and there are a LOT of parts to make these motors get +9000rpm and 170bhp! they are the stock car racing engines that they use to this day. email me for questions.
khizer qureshey

This thread was discussed between 15/09/2000 and 22/09/2000

MG MGB GT V8 Factory Originals Technical index

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