Just signed up to ask a few questions, Have been looking at the site for a few months now and am wanting to build something a little different. My father has a MGB roadster and i like the shape of the GT (coupe) version.

I am thinking of rebuilding one to run with a bike engine, as i love to rev things HARD!!
Can anyone tell me:

What engine is best to use on a heavy car (about 1ton) i have been told a zzr 1400 would do nicley?!
Would the gearbox handle this extra weight? - are Reversebox's stronger?
Has anyone tried to do this before?
Would it need to go through an SVA test?

Any and all help is welcomed!

Cheers

Dave

I don't want to sound blunt but there is no way on earth you'll get a bike engine to reliably pull 1 ton of car around!

If you can get the car down to ~600kgs max (including bike engine) then you've got a chance, if not then I'd suggest a more conventional route of a car engine, maybe something like an S2000 engine if you want it to be reasonably quick and rev happy.

the mgb weighs in at 18.5cwt which is 839.14588 kg

engine and box has gotta be a good 100kg?! I have seen one on youtube with a supre engine in, so im not ruling a car engine out but would prefer a bike engine.

to heavy mate

dont forget your gonna be sitting in it aswell

then perhaps a passenger

youll just end up dissapointed

840kgs isn't quite as bad a starting point I guess, would still need to be significantly lighter than that to make it worthwhile, not only from a reliability point of view, but also because performance simply won't be anything amazing if it weighs 800kgs!

I'd guess an MG Engine / box is more likely to be 150-180kgs combined, but a big bike engine like a busa or ZX12 is 90kgs so at best that gives you a 750kg car with the bike engine installed, still too heavy IMHO unless you fully strip it out and get it down to 600kgs or so, ideally less.

Cheers for that guys, i am already typin away on the web to see what my options are!

if you totally stripped it

fitted a big bike engine

perspex windows etc etc

little heater

youd get it down a bit more

it would be ok but youd still get beaten by a good performance car and youd end up pissed off

most of our Bike engine cars weigh 410-520kg

thats where the performance comes in

my bec has 125hp and weighs 450kg its pretty quick up to 60mph but then you can feel the lack of power compared to a car engine once the air is pushing against you ,with nearly double the weight i think anything under 150hp will be a let down

Like Chris says, ideally you'd need to get it down to about 600kg. If you could manage that, you'd then need a Turbo Hayabusa engine to give it decent performance and they aren't cheap.

Phil

A better solution IMHO would be to do Duratec conversion. Plenty of power and (more importantly) torque to cope with the weight. Still a nice rev happy engine and a better all round car project - again IMHO.

Alternatively if you have the time/inclination/money, then a carbon fibre bonnet, roof, doors, boot lid, wings, seats, lightweight alloy uprights, wilwood calipers, perspex windows, IRS, magnesium wheels and light weight tyres might get the weight in the right ball park.

Even then you'd need a turbo Busa to get anywhere near what you're after.

There is always the option of two bike engines, if the bay was big enough.

Sounds excellent to me All I can say is go for it, try a 1.0L plus engine and you will be satisfied.

Try stripping all the extra weight off and you should have a quick MGB.

Ripping the B series engine and box out and replacing it with a bike engine will have the classic crowd up in arms but you have come to right place for advice, the weight saving wil make up the difference. After all a B series engine and box will weigh around 180kg with 80~90bhp?
A 180bhp R1 engine engine and box come in at around 75kg. No contest.

For me its all about satisfying yourself, and like me, I would love a classic looking car with modern power and underpinnings.

I considered a TR6 with Ford mechanicals but was put off and went down the MNR road when I found out how much a Heritage shell and chassis was. If you've aleady got the car, your onto a winner!

sorry coozer dont want to confuse the bloke

even with the engine change the car weighs !WAY! to much

Gotta agree, a highly strung R1 engine (or any bike engine) trying to drag around 750kgs plus 2 passengers and fuel is simply not going to be reliable nor is it going to be particularly quick.

Its going to be hot hatch quick maybe, but no more, and you'll only do one enthusiastic start before you'll need to change the clutch!

You'll be alright till you come to a hill. MGBs aren't meant to go fast anyway, if they were they would have been fitted with proper suspension. It wouldn't need SVA as you aren't changing the chassis but you might have to have an engineers report for insurance.

I think a V6 engine in an MGB would be nice, get a cheap Mondeo V6 and mate it to a type 9 gearbox, 200 bhp will be plenty for the old girl, loads of torque and a nice sound, parts supply is easy and it'll probably be faster than most of the V8 B's out there.

The bike engines clutch won't take kindly to pulling that much weight off the line, in mine the wheels spin too easily so it helps to save the clutch but in a 700+Kg car you'll probably need a new clutch evey 2 months, unless you drive it like my auntie Vera..... which is not going to happen I'm sure

I have seen a couple of nice K series conversions in MGB's and that would work well but it's been done before. V6 if it will fit !