Help with a high comp M20b25 refurb/install

[Alyman]

I'm after a bit of help with a swap I'm doing. Myself and a couple of helpful Zoners are trying to transplant a prefacelift 2.5 lump into a facelift M40 bay.

Before sticking the engine in it's getting a light refurbishment. New belts, water pump, tensioner as well as rocker cover, inlet and sump gaskets.

I've got a few questions so far:

1. In between the water pump and the tensioner I'm told there should be a spring/pin assembly keeping the tension steady - but this is missing on the engine, and wasn't included with the new tensioner. Is it something that was only on facelift cars maybe?

2. The loom. I'd been under the impression that all of the loom right up to the ECU wasn't essential, just from the c101 plug onwards. Seeing as I was taking the engine out in a hurry I chopped the loom at the phantom bettery terminal where it enters the bulkhead to go through to the ECU (I kept the bit from inside the car too though). In retrospect, this seems to have been a bit stupid. Will I have to reconnect all of those wires together again? I looks that way at the moment.... am I missing something?

3. The radiator - it's prefacelift, from a car with AC. Is this going to fit okay in the space where the M40 one is at the moment or will I need diffferent radiator mounts?

4. The slave cylider - the thin metal pipe going into it got damaged and had to be clipped while the engine was coming out - can I replace the whole thing with the slave cylinder from the M40's gearbox?

5. Anything else you think I might be missing? I'll remember to check the additional wire problem from Brrianmoooore's sticky before firing it up.

Thanks in advance

[Brianmoooore]

1/ Spring and pin have probably gone AWOL as a result of a water pump change when not changing the cambelt.
Few pence from BMW.
2/ Yes, you have been a bit stupid! And totaly unnecessary - the loom comes out so easily!
If this was the pre face lift loom, you don't want it, or the antique ECU, anyway though. Far better to get a post facelift loom, along with the front timing pulley, crank sensor, oil pressure switch and ECU. 320 or 325 stuff will do.
3/ if it fits on the original mounts, then all is well, but I expect you'll need to change at least one. ETK will answer the question for sure.
4/ That pipe is ridiculously expensive new! I'm not sure if the slaves are the same without checking - compare them side by side for pushrod length from the mounting flange. Either way the pipe should be swappable.

[ric325i]

4) im using a 318i ( i guess thats the m40?) slave cylinder on my m30. used it with the m20 too. i dont know if strength is an issue but its working so far.

i would say the pipe work would be the same.

[Alyman]

Cheers guys

I'll order the pin/spring assembly from BMW then, and hope that the slave cylinder won't cause too much hassle.

Regards the upgrade to motronic 1.3, is it quite straigntforward then? Seeing as the engine is out, I've chopped the old loom, the front pulley is off and a lot of the loom is already disconnected it's probably the right time to think about doing it... Is it plug and play or will the car need a trip to the rollers to get it running right? What exactly is required?

I've spotted this loom for sale from a facelift 325i - so I'd still need the front lower pulley and the oil pressure switch? Is that the crank position sensor I see attached to this loom?



Would anything else have to be changed for facelift stuff? The car has the L shaped ICV installed, is there any need/benefit to changing to the T shaped one? Any changes to the distributer etc?

Cheers

[Simon13]

Either ICV will work fine both types were fitted to early and late engines. looking at that picture, you'll need the crank sensor and bracket. Plus the front timing pulley

That loom will go on no problem, dizzy is all the same

[mirage]

nice to c someone who is swaping a m40 to m20b25 cause im doing the same at the moment.my car is RHD and the donour car is LHD.will the facelift 325i engine loom work perfectly if i just connect it to the c 101 cause the LHD loom to the meter cluster is shorter?

[ric325i]

i bet the LHD loom will work, it just needs to be able to reach over.

will you need a RHD mani?

Alyman jaffro might have a spare crank wheel if you need one? im not 100% sure though?

nice sig pic by the way

[mirage]

the engine loom is the same just that the loom after the c101 to meter cluster is too short.....im gonna try use the one from my m40 and see if it works .....any idea?

[Alyman]

OK, went to the scrappies today with Neil (320Touring).

Stuff we got:

Complete engine loom from a 325i
ECU
The fuel rail - I've been told that the connections for each injector differ on prefacelift engines
The HT leads - same as above

Stuff we didn't get:

Front lower pulley (didn't have the right tools with us)
Bracket for the crank sensor (only occurred to me after getting back)

So if Jaffro has either of these Ric, let him know I'm interested.

The engine itself is looking good. The new timing belt, tensioner and water pump are all on now and the inlet and thermostat housing gaskets have been done. The whole engine has been given a clean up and any removable parts have been taken off, wire brushed and given some fresh paint. I'll get some pics next time I'm working on it.

[BadDave]

Aly

I've got the bracket for the crank sensor mate

[jaffro]

i have the spare crank senser wheel here ill pass it to ric a he can send it ya mate

[Simon13]

sump gasket!!!

don't forget that it's a really really sad job with the engine in the car!

[E30BeemerLad]

Brian, you're right about the cost of that flexi pipe that goes to the slave cylinder, it's about £80 at the stealers. I managed to snap the metal pipe where it goes into the slave cylinder when i enthusiasticly removed the M40 donk and forgot to disconnect the pipe.

I'm making up a replacement using brake pipe unions,cunifer and a rear brake hose

[Alyman]

Aly

I've got the bracket for the crank sensor mate

Perfect mate, do you want some paypallage? Or will you be down in Edinburgh at any point soon?

i have the spare crank senser wheel here ill pass it to ric a he can send it ya mate

That's great Jaffro - Have you or Ric got paypal so I can shuffle a few sheckles your way?

sump gasket!!!

don't forget that it's a really really sad job with the engine in the car!

Already bought, just waiting til the engine is in the air before changing it

[BadDave]

Aly

I'll take it off tomorrow mate

PM me your address mate
I'll send it out monday