4.6 Stage 3 MGB GT with a Brand new 5 speed gearbox conversion
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- Опубліковано 7 лис 2018
- A feature video on this project from start to finish plus our road test at the end.
We build up a 4.6 litre Stage 3 RPi Engineering Rover V8 power house with Piper 285 camshaft. Plus an installation of a brand new 5 speed 2 wheel drive gearbox. Feature video and photos of the new gearbox option coming soon. Check our library.
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Shortly after retiring, I bought a factory built 1975 rubber bumpered MGB GT V8 in 2002.Drove on MG Owners tour in Norway in 2006.Had engine and rear axle reconditioned in 2012. Ventured to Ventnor etc on Isle of Wight, UK 2015. Toured around Pyrenees in Spain and France in 2016. MG Owners Club trip to Barcelona in 2017. Used it as fun car and transport to golf club weekly for 10 years too.Sold it in April 2022. Because of that car, I saw places I would never would have visited otherwise. Now in my 80s with many special memories.
I upgraded my B Roadster from a 3.5 to 4.6 using an RPI engine,I got much help over the phone from Chris and Holly, great company to deal with.
I used the RV8 front crossmember and a Hoyle IRS kit on the back end, the car was a joy to drive.
I did the upgrade in 2002/3 and finally sold the car a few months ago, beginning to regret it a bit now.
I'm not going to help here.....................WHAT, you sold it!!!! I'm sure there was a good reason at the time. You never know, you may be able to buy it back one day or build a better one
My Dad (before I was born) had a MG-TD, then (after I was born), a MG-A.
My oldest brother had a New (from factory) '71 or '72 MG-B (we time and distance rallied in it).
I learned the finer points of shifting after practicing in a '64 Corvair convertible.
Finally I had a '72 MG-B that I had painted from a dark green to a British Racing Green like my brother was. ;-)
Why did I watch this? Sitting in the office at 6:30 am waiting to open my business, I usually watch TRex, Bowie or Faces videos. I drove my ex-NYC gas company auction Focus station wagon to work on this beautiful spring morning. I could have driven my MGB V8, 4.6, T5, 3.08 LSD, convertible! Whaaaa! 3rd one I've built, went a bit overboard, RV8 front suspension & brakes, F.A.S.T. fuel injection, stainless fenderwell headers, MGOC SS dual exhaust & Crower cam. I also have a late model Mustang 5.0. The MG is infinitely more fun to drive. Even though I could just make it back home to swap cars I'll wait. Despite all of the current restrictions in place there's no rule against a top down drive on a nice evening. On second thought, thanks for the motivation. Now I have something to look forward to. It will be a long day.
Thank you for your comment :-) Hope we have inspired many to do the same
@@RPIEngineering I'm sure you have, extra power, handling, refinement are always an inspiration. Of course, the cars themselves do a pretty good job too. Far more so now than when they were current I think
The memories this generates. Had a 75 B early model with the plastic bumpers but twin Solex carbs. Drove it for nearly five years from Southern Utah to Las Vegas, Winter, spring, summer, and fall. Engine would overheat at each stop light during the hot months so I took a windshield washer tank and pump, laboriously filed notches every 4 inches on a copper tube that formed the outside of the radiator then installed a foot button (from horns) to spray mist during each stop. Would empty the reservoir between I15 and Eastern Ave so I would refill before heading home. July and August would literally burn your feet so I installed aluminum sided insulation under the floor rubber. It helped but didn't make the interior any cooler. Look back at those years and now think they were the most exciting in my professional career. An MGB, Mahler, and a 32 oz Dr Pepper. Doesn't get much better than that.
The original 3.5 V8 sounded pretty damn good!
Yes when setup and running well the 3.5 litre engine still has good power and flexibility
just got my hands on a 79 MGB, 73k, 2 owner... love it!
As the long-time proprietor of a US-spec Midget 1500, that BGT is the stuff of dreams. What a stunner! There but for money go I...
Drop a 150hp engine in your Midget. Plenty of modern 4 cyl FI engines that will weigh less than the 1500 and have more go than any stock MGB. A Midget that will go 130 mph and blast by most anything on a mountain grade is a new world of fun. Lots of net info on engine upgrades for Midgets and Spitfires with that sad 1500. Go for it. 🙂
Yeah, the Rover K-series is a popular conversion in the UK. They aren't available here in the US. :-/
@@rizzlerazzleuno4733 Nooo drop a triumph rocket 3 motorcycle engine in it. Keep it nice and light.
What a beautiful BGT!
Thank you. We are very lucky to get such beautiful cars in our workshop.
Nice upgrade
I've suffered the dreaded British sports car lust (possibly an American phenomenon) for nearly 50 years. After giving up on a near dead 66 MGB my father purchased from a neighbor for $60, he asked if I wanted it for my 18th birthday. Of course I did! Soon after getting it going I saw a Hot Rod engine swapping book article about a Buick 215 in an MGB. Next up I looked at buying (and declined) such a swap where the shifter of the 3 speed came out through the radio support. A few years later I ran into Glen Towery, from whom I had previously purchased used parts, at a show with his "Purple Porsche Eater" converted GT. He had been to England and purchased 2 sets of conversion parts from Dave Vail at the V8 Conversion Co. Within a couple of days I owned the second set. Another acquaintance happened to have a '63 Buick Skylark with 215 4 barrel V8 which his wife wanted gone. It was mine for a tow & a case of beer. A few weeks later I had my first MGB V8 and have never looked back. My current car was built about 20 years ago and unfortunately sat for about 10, initially derailed by college tuition. This car incorporates parts from just about every known supplier of V8 conversion parts. I am sure I have purchased parts from RPI at some point but have lost track now. I have had it back on the road for about 8 years now and still love to go for a spin in it. As to the dreaded BSC lust, although a have continually had a B since that first one I also had a '68 E-Type 4.2 FHC for 14 years, some Midgets & Sprites, an 1100, and have owned an Austin Healey 3000 MkIII BJ8 for about 40 years, sans engine. Last summer I found a running car with a derelict body so now I have two! I am afraid the beauty of those cars may temporarily distract me from my V8. But never totally.
Instablaster...
@@baylordanny978 I'll take it over my 420HP 2013 Mustang 5.0 anyday. No comparison, fun wise. The Mustang does have A/C but that's on the wish list for the MG too.
great content
Thank you
In the early 90's I did almost the same swap on my BGT, I fitted a 3.1 Buick V6 to a 5 speed camaro box, I used the OE GM fuel injection, same wheels and hood louvers, Paint in GM Black Rose, a Corvette color. Where is it now.
Nearly three decades ago I think it was recommended I put a five speed Ford Sierra box in the MG V8 I was driving then, but do correct me if my memory is letting the side down. And if so was that a good swap? I guess this Mazda box is the modern alternative. Should never have sold that car but it was a rubber bumpered one that didn't quite feel proper
Is there a pilot bearing? Where is that whine noise coming from?
Very nice. Shame about the dreaded diff whine. Plus it is too low geared really. Not sure were they 3.7 or 9. Would easily pull 3.5 if they were available. My thought for the roadster build was a complete rear end from the MX5 MK3 sport tech , which has the 6 speed getrag box & a limited slip rear diff.
which mazda’s gearbox is it
What torque can the mazda gear box take ?
Which model transmission are you installing? The M5OD?
Gorgeous car and brilliant upgrades reducing weight massively i imagine with that new gearbox as well.
I wonder why it wasnt converted to fuel injection?
Customers spec on this was keep it simple however EFi is possible and we have done them before. Overall power between a good carb setup and EFi setup should be much the same however EFI will always have more refined throttle feel etc.
RPIEngineering yes, and better fuel consumption and lower emissions.
Where I can find information about the T5 matted to the Rover 4.6?
Won't take the torque.
If you really want to test the worth of a chassis take it out on “The Ring”. Great place to test out the handling.
I'm not sure I could justify a "Ring" trip to customers under the scope of "testing" :-)
Hi ..Can this V8 engine and gearbox be fitted to a MGB 1966 ?
I think about the same v8 conversion. so i have to buy a 4.6 v8 with a mazda 5 speed conversion from moss europe or frontline and v8 rear diff? Maybe i would like to ask a few about this.
Hi,
Yes we can supply oyu with engine and gearbox etc however it would be best to discuss this via email on info@v8engines.com
Why not use an Ford 289 cu. in. 271 hp or the Shelby 306 hp version? It’s an extremely narrow and compact engine capable of extremely high reliable power output. I will admit the Rover engine is a capable engine BUT its weak link are the cylinder head attachments. My favorite vehicle was my 2000 Range Rover 4.6 HSE. EXCEPT for the cylinder head attachment failures. Yes 3 times!
Nice, but a modern fuel injected turbo 4 cylinder (example:Ford 2.3L turbo) would be more than enough power for an MGBGT and being lighter would improve handling, and bonnet louvers would not be necessary. And better gas mileage than a V8. Just sayin. But I did enjoy the drive around the country roads. 🙂 👍
Well, you a bit incorrect about the weight being a problem with the Rover V8. My 'B lost about 40 pounds over the front axle when the aluminum block replaced the old 1.8. Mine was also set with with Sebring kit, and recently sold on Bringatrailer. Mine frankly wasn't near as nice as this one, bringatrailer.com/listing/1963-mg-mgb-v-8-conversion/
Its not going to have that Classic V8 burble and bottom end torque that the V8 has though.
Saw a SR20DET engine fitted in a MGB GT some time ago on the internet though and was certainly different
@@RPIEngineering A friend is installing a SR20 with 5 speed in a MG Midget. It also has a Corvette front suspension/steering and a Jag rear end. Gonna be awesome whenever it gets finished. 🤔
@@qqq854 Yep, just about any modern 4, 6, or 8 is going to be an improvement over the original 1.8. It is just astounding that there are so many 4s that have over 200 hp. All that being noted, it is fun to go to auto shows and see a completely original (or restored) MGB. The B is one of the cleanest sports cars designs, but with the bonnet closed who knows what could be hiding in there......that's why I don't like louvers or scoops.
@@rizzlerazzleuno4733 First engine I ever completely rebuilt and upgraded was an SR20DE lump, still love the SR engines but afraid the RB trumps it some what :-)
Just wondered why you used a Mazda gearbox? I have converted 3 MGBs to V8 on each one I used the RoverSD1 5sp gearbox (which is bullet proof) and Rover P6 2000 prop shaft all bolts straight in.
Because the LT77's and even R380's although very strong most are badly worn now and parts for them are tricky to get. The Mazda box is a great little box thats brand new, it had a great feel on shifting gear where as the LT77's and R380's where always a little more agricultural :-) More explained in this video here
ua-cam.com/video/fvTfL7Bh1RM/v-deo.html
What sort of power & torque figures did this one make?
Around the 280 bhp mark and up to 300 lb/ft torque. As you can tell from the video though the torque comes in really early
That's pretty healthy, enough to give the car a good workout!
@@RPIEngineering Unfortunately that low rise manifold will be costing you a lot of BHP, I suppose you did not have much choice really. Even the Edelbrock Performer manifold starts to become the restricting factor on a tuned 4.6, port matching helps a bit!
how d'you get the air out of that top hose?
Push the highest point down the small amount needed whilst filling. No issues at all.
How much HP can the Mazda g'box handle?
Hi,
We cover that in this video about the gearbox
ua-cam.com/video/HbVHST5qZ1I/v-deo.html
I notice the exhausts are not linked, is this not required for this engine.
Nope no need, we see cars with both balance pipes and without and see no difference in how they run. Makes a difference to how they sound depending on how large the pipe work etc is.
I have a question. Why not use a Ford 4.7 liter (289 cu. in.) engine? It’s light, narrow, tons of factory and aftermarket parts available. Hey if it was good enough for Cobras and Mustang GT350’s to blow everyone’s doors off in the 60’s. Why not now?
I've seen lots of different engine swaps in different cars before. Even a SR20DET Nissan turbo engine in a MGB however as the MG B GT was factory produced with the Rover V8 engine fitted many customers like to keep it this way and as its the engine we have focused on for the last 30 years its why almost all our videos etc are Rover V8 based.
RPIEngineering, how about head gasket issues? I know my Range Rover had to have its heads redone twice. I loved the 2000 4.0 SE that I had but mine was a very limited production model that met California emissions standards. You could only use parts for that particular model and that year only. I was going to do an engine swap but could never get answers from Land Rover on bolt patterns on the transmission bell housing. I wanted to install a Chevrolet 400 small block in it because it was a high torque engine. I finally sold it to my repair shop owner. Even with the tons of issues it had I loved the old girl.
@@arttafil6792 If the engine is built properly and cared for well then there should be no head gasket or block cracking issues.
RPIEngineering, no block cracking but head gasket and warping of the heads. The second time it was repaired the left head was.003 out and the riright head was .004 out. Once they were planed it required a thicker head gasket. I had a solid copper gasket installed. All new grade 8 head bolts were installed and sequence torqued per my instructions. Old time hot rod method.
Running the vac advance off the timed port is an emissions dodge, you will get better results running vac advance off the non-timed port assuming you can find a suitable vac canister. You can then run much more idle and low rpm timing but allow the timing to back off if required when you floor the throttle.
Not from what we have experienced in 30+ years and real world road driving. Throttle response is greatly increased with vac advance on a timed port. When the MG R V8 went off to Japan they moved the vac advance to a non timed port and its a known correction to assist in getting the vehicles to drive better to place it back to the timed port where rover designed it to be (along with correct mapping etc as well)
However I do see the logic behind your explanation with decaying vacuum under opening throttle however in the real world on a dizzy setup it just does not translate to throttle response and drivability for a road car.
@@RPIEngineering Please don't assume that I'm not driving in the 'real world'. There is no way that the throttle response can be 'greatly increased' by running off the timed port because by definition it won't have any effect at very small throttle openings. The only time you would see an improvement using this port would be if the vac canister was not well suited to the signal from the non-timed port of the carb, (which is very often the case with the 500 carb), in this case the fix would be to modify the canister or find a suitable one, not just plug it into the timed port.
Until stupid emissions laws came into force all cars run vac advance on a non timed port, for example old Minis running A series engines are setup with around 6 degrees of timing at idle with the vac disconnected, the engine runs very poorly due to the retarded timing, you then plug the vac tube back in and the idle becomes stable because the canister has added around 14 degree more timing, the idle timing is now up around 20 degrees. Its the same thing with the Rover engine, just as a test set the timing to 10 degrees or even more if you wish, then with the engine running slowly add more timing, the engine will pick up speed because it wants more timing, from memory my 4.6 stage III needs about 24 degrees. Of course this would be way to much if you then floored the throttle because the VE would go up which means the initial cylinder pressure would go up, the result is that effectively the timing would be too advanced. (we are aiming for peak cylinder pressure after the plug fires to occur at around 14-20 degrees ATDC).
I run around 32 degrees total timing so on the face of it it would seem that I only have an advance range of 8 degrees (32-24) but this is not the case because my vac system can back off the timing by 14 degrees, so if I floored the throttle at idle my timing would back of to 10 degrees (24-14). At the same time my all in timing when there is a high manifold vacuum is actually way more than 32, its 46 degrees (32+14).
It is just about possible to setup a system with the above figures using bob weights and a vac canister although I have found that any of the standard canisters need opening up and modifying, i run a fully programable MSD 6530 ignition system with a modified (locked out Lucas dizzy, all the guts removed and a MSD pick fitted). It also runs a MAP system which allows me to setup the vac advance system.
Even with in the limits of the standard ignition in conjunction with the 500 carb when I have modified such systems the driver says that the car now pulls in third in the same way that it did in second gear.
@@sidecarbod1441 We will have to agree to disagree. There is often more than one way to get to similar results. For us we have always seen great results as our customers have experienced, is seen in our videos and the tens of thousands of engines that we support remotely have reported back.
@@RPIEngineering Just try advancing the timing on an idling engine until you reach the point that the idle speed stops rising, then measure the timing, even on a bog stock 3.5 with a short duration cam it will be up at 14-16 degrees. This is telling you at with the throttle virtually closed the engine needs that amount of timing at idle, it will therefore need more timing as the revs rise assuming that the VE still remains very low. As to thousands of customers reporting back, well "in the land of the blind".....
Is that a Rover V-8?
Yes it is
What diff ratio you running ? sounds like it needs another gear.
Its the standard MGB GT V8 rear axle. Feels great to drive however with a 4.6 under the bonnet it would probably pull another 3 or 4 gears :-)
@@RPIEngineering what torque can the gearbox take and have the ratios in the gear been changed to suit the V8?
@@mgbroadsterJ The diff ratio on the Mazda and the MGB GT are identical so the ratios in the gearbox are left exactly as they are and it feels like a great setup when driving.
The box is rated up to about 250bhp however there are lots of turbo Mazdas running 300bhp and not breaking the gearbox so the customer with this car was happy to install the 275bhp (ish) 4.6 engine in front of it. Of course subjective to traction and driving style. For sure if you were drag racing then you would want the T5 box
@@RPIEngineering The best ratio rear axle is a MGC diff 3.3:1, MGB standard is 3.9(too low) and MGBV8 is 3.08:1(too high)
@@biggles145 Subjective to what you want to use the car for really. There is no idea final drive ratio for everyone, nor is there one engine build that would suit all.
Any reason why you didn't go EFI?
The keep it simple approach. We have gone to EFi on the MG's in the parst with great results however this carb does so much of what you need without the expense and extra work involved for EFI.
@@RPIEngineering Thanks for the quick reply. I am in the early stages of planning an MGB GT conversion using a Rover 4.6. I assumed that EFI vs carby was an easy decision, but from your reply it seems I may have to do some more homework. When you say "expense and extra work", is that in the context of this particular project and the customers desired time frame and cost? If like me you were starting with a blank canvas, would EFI be viable? Sorry for long question, but with your experience I value your opinion.
@@ricbarker4829 Each project is of course individual. Out and out power is very similar between EFI and carb. Efi will always win in terms of drivability as with computer mapping you can get fuelling spot on under all circumstances where as with a carb there is sometimes a small area that is not quite right, however that being said I'd be hard pressed to find that scenario when out driving normally.
Best to me a call on 01603 891209 (Ian) to have a chat about the different setups etc as far better to bounce ideas back and forth on the phone than emails etc.
Again, thanks for replying and the offer for a chat. I might just give you a call when I get closer to trigger pulling time. Like I said, I am in the early stages of planning the build and still trying to get my head around the legalities here in South Australia when it comes to putting a 4.6 into and MGB.
@@ricbarker4829 AH yes finding out what emissions laws you might need to comply to etc might effect what fuelling setup you go for if CAT's have to be used.
OK, but what's the point of all that if you're expanding the engine capacity and its C02 output?!
To annoy you. Job done.
is it still an mgb ?
:-) It depends if your a purist or a motor head. From where I am sitting its one of the nicest MGB's I have ever seen and been lucky enough to drive.
However if you are looking for an all original MGB GT V8 then for sure this is not that.
no gear shifting shoot....
That hood/bonnet doesn't look flush with the fender/wing.
My brothers new 1971 or 1972 MGB and my used 1972 MGB were fine but it's a common issue due to the poor support structure from the hinges to the leading edge.
@I'LL BE BACK ! BS ! My 1964 B original aluminum hood/bonnet is a perfect fit and as new, never wrecked or modified, no body work.
How much would this cost to do?
Hi,
Every car is different depending on what is needed etc. If you would like to email through to info@v8engines.com with what you have already etc we can then advise you better.
RPIEngineering its a 76 mgb gt
@@alterra9774 Hi,
Please email through to info@v8engines.com with your current setup (i.e the details you have already given along with current engine setup etc)
I can then email you a detailed quotation, which is far to much to post on a UA-cam comment.
Kind regards,
Ian
RPIEngineering ok
RPIEngineering it says the email wont go because “user hasn’t enabled emails to this address”
and what does it cost to run this thing lol
How can I contact you?
Normally best to email info@v8engines.com, you can also call us on 0044 1603 891209
Fake farmers in the field? What do you mean?
Sorry, at 10:33 in the video I had spotted some steel cut out farmers in the field. I assume bird scares but the camera did not really pick them up.
@@RPIEngineering scarecrows
stage 1 or 2 ...its not hittin'
This engine is fitted with our Stage 3 heads.
Them terrible slave cylinders should be illegal
Bad idea on the gearbox, Maxda don't make good ones, Toyota do.
Well the Mazda box is doing everything that we need it to at the price range / power level it is rated for.
Nothing wrong with Mazda box, very strong!
Robin Horton hahahaha you really don’t know what your talking about !!