M50 Developments - considering an M50? Read this.

[Brianmoooore]

Sorted my clutch problem out,
the gearbox had an E30 slave in it
This is the difference \/ E30 on the left / E36 on the right

Right, glad that's sorted, because I've got an E36 box and a M20 flywheel on mine and didn't have any problem!

[DanThe]

You obviously had the correct slave then Brian, did you have to shave the flywheel?
By the way, the output flange on my gearbox has 12mm holes in it.
I got hold of an E36 donut and bolts and drilled the prop flange out today with no problems

[Brianmoooore]

Flywheel was bog standard, and I used an E36 320 gearbox and slave cylinder.
Still haven't checked whether I have 10mm bolts in 12mm holes.

[DanThe]

Maybe slight differences in the blocks? I had to do this to mine

Before . you can see where the bolt heads were touching


And after, with 7mm removed


Also, did you notice the slight difference in ring gears? I used an M20 starter

[Brianmoooore]

No problem with anything touching the back of the flywheel that I can recall.
M20 starter was used.

[stevetigger]

No problem with anything touching the back of the flywheel that I can recall.
M20 starter was used.

Im using the starter that came with the engine!

[Brianmoooore]

Im using the starter that came with the engine!

If you're also using the flywheel that came with it, then that's correct.

[stevetigger]

Yep, Just bunged it all in there!

[irish320i]

after reading through the whole topics eyes bleeding at this stage just got my 525for an engine need to no what gearbox works best and if someone has what rewiring i need to do i sorry to ask all this but this car is my everyday 120miles so i need to know what i need to get before i start thanx for any help

[DanThe]

The ZF boxes are supposed to be stronger with better syncro's, but you will need either an M3 prop or to have a E30/E36 combo prop built.
If you use the Getrag with the smaller of the two output flanges you can use a 325i prop if you drill the prop flange holes out to 12mm.

Im sure there is a pin to pin wiring list about somewhere

[irish320i]

have any yous had any problems when you removed the cat on the m50 engine did yous remove the sensor or mount it in the new exhaust system

[DanThe]

Working on this at the moment
Ive had it running with no sensor fitted and it wont tick over smooth at all.
With the sensor connected but not fitted it idles perfectly but tries to cut out at around 3000 rpm.
With it connected and fitted it still ticks over a bit 'lumpy' but revs a lot more freely/smooth.

I have got a full Scorpion exhaust system so it may be due to less back pressure but im not sure yet

[irish320i]

has anyone whos done the swap said how they ve got round this prolem do you need a programable ecu or is there another way round it

[Brianmoooore]

has anyone whos done the swap said how they ve got round this prolem do you need a programable ecu or is there another way round it

What problem do you mean? Only problem I had was the ECU fault light coming on untill I worked out that the ECU needed the carbon cannister solenoid valve to be connected to keep it happy.

[DanThe]

has anyone whos done the swap said how they ve got round this prolem do you need a programable ecu or is there another way round it

Never heard of anybody compaining of it before

[irish320i]

just read this again and it means the gearbox from my 525 won t work will i be able to use my 320 box and shaft if i do what flywheel do i need to use and another small thing the info for doing the wiring is there any difference in it when the car was originaly a 316 were have mustt people cut to join the looms have any of yous tryed to unpin the plug to connect it

[DanThe]

No way of removing the pins without damaging them, you can buy the pins from the dealer though

[irish320i]

i can get a pin crimper as i work on aircraft and they use a lot of plugs like the engine connector one they also have pin removal tools are the wires going to the connection plugs the only ones i need to change i sorry to ask so many questions but im trying to find out as much as i can before i start got my tubular manifolds today 50 euro not to bad i thought

[jmc330i]

No way of removing the pins without damaging them, you can buy the pins from the dealer though

You can remove the pins and reuse them, it just takes a bit of patience doing each one very carefully. I did this with a couple of the pins that I wanted to move.

The only problem with the pins from the dealer is that they come with a length of wire already attached, so you still have a soldered joint in the wire.

[irish320i]

cheers for that im just trying to get this engine as ready as i can before i take my car of the road

[DanThe]

What did you use to remove them James?
Ive removed a couple but I cut the plug up to get them out

4 pins that need straightning out IIRC


Ive got the lovely job of extending the ECU wires next week
so I will be doing a fair few soldered joints

[Brianmoooore]

It's easier to use a E30 C101 plug with a length of original E30 loom still attached, and join all the wires inside the E34 wiring box. You can leave the E30 wires that go to the ECU longer, so that you don't have to extend these wires when you lengthen the ECU branch of the loom.

[irish320i]

sorry to seem stupid is the wiring box the wire holder that runs across the back of the engine

[Brianmoooore]

sorry to seem stupid is the wiring box the wire holder that runs across the back of the engine

That's the one I mean. E34 box hangs neatly from a couple of studs added to the heater accesss panel.
Looks as OE as the original E30 one, and much better than the E36 one.

[irish320i]

thats sound thanx for that will be starting that tommrow were did you mount the 3 relays that come out with the loom of the e34

[Brianmoooore]

Mine ended up on a bracket near the top mounting bracket of the steering column, with the ECU in the standard E30 position. (ECU wires extended).
Next one I do (when a couple of E34 sumps come my way), I will probably evict the battery to the back end, and put the ECU and relays in a waterproof box on the front battery tray.

[jmc330i]

What did you use to remove them James?
Ive removed a couple but I cut the plug up to get them out

Ive got a pin removal tool from RS.
It takes a bit of practice to use and get the pins out clean, but if you get them out carefully enough, you can use a very small screwdriver to lever the lugs that hold in the pin in place back out again.

I also bought some pins from the dealer with the wire attached, and carefully unpicked the crimp to remove the wire. Again, if youre patient and careful enough, you can reattach a length of wire using the original crimps.

I forgot you guys were talking about the M50, so I would suspect that Brians way of connecting the wires in the E34 wiring box would be easier as you need to extend them anyway.

[irish320i]

my engine is from an e34 so i think the ecu connector might just about make it into the car not sure yet

[Brianmoooore]

my engine is from an e34 so i think the ecu connector might just about make it into the car not sure yet

It'll make it into the car, but only just. Won't reach anywhere near the stock ECU position.

[irish320i]

im using a m20 from a e34 at the moment cause my car was a 316 to start and as you say it fits into the car but only just may just move my battery to the boot would nt take to long to do and would make a bit more space under the bonnet

[Brianmoooore]

im using a m20 from a e34 at the moment cause my car was a 316 to start and as you say it fits into the car but only just may just move my battery to the boot would nt take to long to do and would make a bit more space under the bonnet

Bit of confusion here I think! This thread is all abut M50 engines.
E34 M20 engine is the same as the standard E30 325 engine (except for a few bolt on external bits. You're going to need bits from an E30 M20 engine to do this swap, so get the correct loom as well.(Although I don't know what, if any differences, in the loom there are).

[DanThe]

I think what he's saying Brian, is he has an E34 M20 engine fitted at the moment and is about to change to an M50

[Brianmoooore]

I think what he's saying Brian, is he has an E34 M20 engine fitted at the moment and is about to change to an M50

I see that now. Shouldn't post five minutes before the start of a GP I suppose

[irish320i]

thanx for that is what i meant about the m20, just had a look at the loom of the old 316 i have in the garage was gonna use the plug of it to wire onto the m50 loom so i can have it all ready to put in but the colours dont match the ones given ealier in this thread just have to find one in a scrapper from a 320 to cut of as had a look at my car and the m20 plug matchs the ones given in the thread

[DanThe]

Dont take any notice of the colours mate, they vary for some reason.
Just work of the pin No's