11 replies to this topic

[Dev]

take out an mpi 1275 and replace with a carbed engine?

talking to guessworks last night i need to move the rad and wiring? anything else?

also how much is this likely to cost? i dont have a crane at home but do have a friendly spanner man.

cheers
Dev

[Wiggy]

You'll need to change the fuel pump. Not sure if that entails a new Fuel Tank or not?

[Guess-Works.com]

basically strip the engine bay.... you may even have to change the subframe as the dizzy will be blooming close to the grill, as will the alternator... because the engine mount points were moved forward to accomodate the MPI unit, although I've heard that turbo boys have used the MPI subframe as it give a little more access at the back...

You'll also have to take the alarm out, and the air bag, because the control units will come out with the loom.. you may actually find there's a lot more room under the bonnet than you thought :cheese:

[Jammy]

You will have to change the subframe. As Dan said the other day, if you mount the carb engine on the subframe it will pull the gear linkage forward as well, which will put strain on the mounts and could cause them to fail.

Good thing is you can get decent condition second hand subframes for a few quid, scrubbed up, waxoyled and hammerited, it'll be a lot less than paying the £100 for a new one!

[Guess-Works.com]

But surely the gearlinkage on the MPI will be long enough or are you telling me the linkage changes on MPI gearboxes ???

[Jammy]

I'm not sure, just going by what Dan said, I'll see if I can find his post...

Edit: Can't find it, but I'm sure he was talking to someone who had re-drilled the holes in a subframe, and that this was wrong for some reason.

[chairchild]

MPI subframe mounting points are the same as an SPI AFAIK - so plenty of space for dizzy and alt (even if it IS a bit squished!)

But if the MPI alarm is actually part of the main loom (unlike an SPI, where the engine loom can be totally seperated from the main loom) then you'll have to rip out the whole loom to replace it with an older style one if you're to ever get it working without the ECU - which controls the immobiliser




Or you could just ditch the injection inlet, slap on some carbs (with a few small mods) - and have the best of both. Fuelling of carbs, ignition of an MPI :wink:

AFAIK, the ignition purely goes by MAP and TPS sensors, so you wont need the lambda sensor

[AlexM]

are there any legal things to watch out for, how about emmissions?

[Kerrin]

HI all

I am changing SPI to carb. the subframe holes are only 1/2 an inch further forward so AFAIK there would still plenty of room for the Dizzy as long as front mount rad is not used.

The gear linkage looks the same but it wouldnt be too hard to bend or change the mount to suit 1/2"

As long as the sub frame and corresponding linkage is matched you should be fine.

I have read that the standard manual pump will pull through the injection pump in the tank.

or fit a electric pump in the boot if required.

I am changing my tank to an older type so have not got this problem.

Why are you changing it anyway. would it be better to recon the engine you have?

[Dan]

As above it's fine as long as you use the gear linkage and steadybars that go with the subframe you are using rather than the ones from the engine and gearbox (assuming you aren't trying to fit a remote change obviously).

The engine is as you say 12mm closer to the grille and the frame is the same as the SPi one yes but don't assume that that means the carb engine will fit fine. Remember that the SPi dizzy is about 25mm shorter than a carb one as there's no middle 'guts' section in it, it's just an empty box. So you may well find you have trouble between the HT leads and any water shield you have fitted.

The wiring from the MPi is pretty well integrated with the ECu's from the engine, alarm and SRS as far as I know. You may well be able to save it if you open the loom right up and strip out one wire at a time from the fuse box back, just keeping what you need but it would be a headache. If you did this though then you would be able to keep the nice internal fuse box. I would have a go at that for you if you needed. It's easier to take the loom out in an MPi as it doesn't go through the headlining but under the carpets. It wouldn't take too long to do that if you knew what you were doing.

Be very careful when disarming the SRS as the system is full of explosives. You need to remove the battery and leave the car overnight basically to allow the system to discharge. It has it's own power reserves and if you just pull the fuse and start work it could all go off still.

You would also need to put normal seatbelts in after disarming the system.

If you do swap the engine the new one will need to be from pre '92 with documents to prove that in order to pass emissions. You've got almost no chance of passing the test with carbs.

For the same reason you can't carb the engine you already have.

There could be all kinds of legal and type approval implications here that your insurer wouldn't like but I can't say for sure either way.

[minidaves]

carb engine will fit in the tpi but why do this?

dave

[chairchild]

easier power - MPI's cant really supply power above 90Bhp (unless you use an aftermarket ECU, or bodge it with a presure regulator)

and if you want proof of a carb dizzy working on an injection subframe - ask Bud666 how his is running :wink: