1275GT motor v newer MPI motor

1275GT motor v newer MPI motor

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p490kvp

Original Poster:

728 posts

255 months

Thursday 30th December 2004
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Hi - I'm after a Mini to do a few road rallies in over the winter.

Now it really needs to be a Mini with a bigger motor and so the choice seems to be either the newer MPI motors or an old 1275 GT.

What is the difference in these motors?

Also anyone know who does a decent roll cage for Mini?

Thanks.

guru_1071

2,768 posts

241 months

Friday 31st December 2004
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if you are going to do road rallies i would go for a older mini. the modern m.p.i wasnt designed with any sort of compatition in mind - it was designed to be quite, economical and comfey, and would not be the slightest bit competative without serious cash input. safety devices make a whole rake of differant cages, to suit all sort of applications and regulations.

there are a few people rallying the s.p.i coopers - these seem to do okay as far as reliability go - look how competative mighty minis is, but for a 'proper' rally mini you will need something you can bolt a set of carbs onto!!! and really get you teeth into the engine and box.

hope this helps

p490kvp

Original Poster:

728 posts

255 months

Friday 31st December 2004
quotequote all
Thanks for your help with this.

Yeah to be honest the road ralying I do is purely for fun and whilst I drive flat out it doesn't phase me too much if I'm off the pace - either as car or driver.

Having said that given I'm buying a new car - since I rolled my last road rally car - I should get one as fast as my money will allow.

I'll look at the 1275GT route then - although finding one at the right money isn't easy! Anyone selling one?

swindorski46

1,017 posts

290 months

Friday 31st December 2004
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personally, I wouldn't bother sourcing a 1275GT engine, any Carbed 1275 would be very easy to upgrade.

Echo the points about the MPi. There's not really that much that you can do to them without expending wallets full of cash.

danwebster

503 posts

241 months

Friday 31st December 2004
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First question is how much money do you want to spend on an engine. Next is how reliable do you want it to be and how long do you want it to last.

If you want something thats going to work well and last a while I wouldn't consider an old engine unless I was going to strip and rebuild it. When you consider that the youngest engine you will likely find will have 60k miles on it, and you want to road rally it, ie: you want it to work well and be reliable.

In my opinion, if you have the time, money and inclination I would build yourself a new motor / rebuild an old motor.

jeffriesmullet

134 posts

249 months

Saturday 1st January 2005
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the way to get an mpi more powerful is put an earlier g/box on it as the diff is different so i say for reliablity mpi with a different g/box

love machine

7,609 posts

242 months

Saturday 1st January 2005
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MG Metro engine A+
Set of 1.5 Su's
Lightened Flywheel/backplate.
1275GT/1300GT gearbox
649 cam/ S rockers should be the deal for a crazy engine on the cheap. Should be easy to set up. Do the cylinder head work yourself. Run about 11:1 CR and it will fly. Homespun exhaust.

Secondhand engines are a minefield. If you can't see it in bits or see it running, you are risking a load of money. Take this lesson from someone who has learned the expensive way.

I have a SD 6 point cage which stiffens the shell up noticably. Before you try fitting one, ask someone what the trick is.

I managed to break my switches and column cowl installing mine. As well as scratching the paintwork. On my 66.

British_Mini

56 posts

238 months

Monday 3rd January 2005
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I think the 1275GT engine is (in standard tune) relatively low output for a 1275cc?

Metro or later cooper (or any cooper for that matter) is probably better engine to look for.

In terms of reliability, I'd say although MPi may go wrong less often than a Carb/Dizzy set up, when it does go wrong (which it will, lets face it, it's a Mini) it's harder to find the fault because there's more bits to go wrong. Others may disagree...

danwebster

503 posts

241 months

Monday 3rd January 2005
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Its a common misconception that just because its a mini it'll go wrong. The fact is it will need more regular maintenance than a modern car to keep it alive, but it is a 45 year old design of car after all.

Chances of finding an old engine that won't need any work to keep it running well are slim unfortunately as not many people realise that mini's aren't modern cars.

rougeleo

213 posts

245 months

Monday 3rd January 2005
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go for the GT or a 1275 Cooper S

cooperman

4,428 posts

257 months

Tuesday 4th January 2005
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The 'A-Plus' engine is a better bet than an old 1275GT, if only because the crank is stronger.
Carbs are the best option, although the MoT may preclude this with a later car. IMHO the best set-up is either twin 1,5 SU's or a 45 Weber, both on a good manifold with an LCB exhaust. Personally, for optimum driveability, I prefer the SU's.
Whatever you do, don't use a 649 cam. It's too cammy and is really outdated compared with more modern cams like the Megadyne 286, which is what I use in my 112 bhp 1964 Cooper 'S' Historic rally car. For road use combined with some road rallies, you might be better going for a 276, or even a Metro GT cam. The Aldon Igniter dizzy is great and Aldon will build one with advance to suit your engine spec.
The head can, as said earlier, be reworked to an acceptable level yourself, so long as you have the necessary air compressor and a die-grinder.
Change the Verto clutch for an earlier type to rally spec. A steel one is not really necessary, but lighten the standard one and fit a wide starter ring.
Ideally fit a straight-cut close-ratio gearbox with a very low final drive. If you are using 10" wheels (that's best), then go for a 3.9:1 final drive. If using 12", then a 4.1:1 is better. Rally cars must be very low geared, as they spent their time at between, say, 40 mph and 80 mph, very rarely any faster.
You could do well to look at the new Enduro regulations for standard cars under 1400 cc. My Enduro car, a 1990 Rover Mini Cooper, has about 83 bhp at the flywheel, didn't cost a fortune to prepare, and seems competitive in relative terms (we were lying 8th overall out of 117 starters on the recent RAC Revival until I crashed right near the end).
For a roll cage for competition work I will only ever consider the full cage from Safety Devices.
Remember that for road rallies your car must not be too noisy. A twin box silencer is a must and I use a centre-exit RC40 with a Maniflow 'cherry-bomb' upstream of it. It's within the limits then. Make sure you have welded skid plates on the exhaust.
Don't forget to raise the suspension a bit and fit a good sump guard. With a sump guard fitted, plus a couple of decent spotlights, you do really need an oil cooler. Also, make sure you run all the lines (fuel, battery and brakes) inside the car - that's a real must.
Email me personally for any more info about rally preparation of Minis and I'll be pleased to help. The beauty with a Mini is that what needs to be done is well defined and any half-decent mechanic can do most of the labour themselves. You can find bits 'on-the-cheap' as well. A properly prepared Mini is reliable, so long as it's serviced between each event.
Of course, the most important accessory for a rally car is a good navigator - it's no good being the fastest competitor going in the wrong direction!