320i to 325i engine swap

[groselha]

Hi,

I'm thinking in swap my original m20b20 to a m20b25 engine.
What i need to change?
The engine loom is the same?

Thanks

[Dave_M3]

If both engines are pre-facelift or both facelift, its just the engine and ECU you need to swap and possibly the gearbox and oil-cooler if you want them.

51mm struts and 325i brakes would be a good idea too or later on when the brakes or shocks are worn out.

[groselha]

If both engines are pre-facelift or both facelift, its just the engine and ECU you need to swap and possibly the gearbox and oil-cooler if you want them.

51mm struts and 325i brakes would be a good idea too or later on when the brakes or shocks are worn out.

Thanks.

If the engine is pre-facelit, what i have to change?

It's for a 89 touring.

Best regards.

[Dave_M3]

The engine managment is a different system so sensors, plugs etc are different but it all can be adapted.

there's a threads on here somewhere with all the info on doing it anyway so best a read through a few so you know exactly whats involved

[tomcat2040]

Dunno if this is still in the works, but assuming both engines are the same side of facelift (i.e. both pre, or both post) then it is totally plug and play.

Did the exactly same swap a few months ago and took us 14 hours

The viscious fan is a b*tch to get off >_<

[sihooker]

The viscious fan is a b*tch to get off >_<

A sharp tap with a hammer, the 'wrong way', on a 32mm spanner and it's away! If you want to upset Mr. Moooore you could always use a chisel...

[eddie124]

Hi all,

Sorry for barging in, but my 320i Touring is exactly in the same situation, but the bloke who did the conversion can't be sure of the 325is' year of manufacture, it's probably pre-facelift (86-87).

In this case (89 Touring with pre-facelift engine transplant) what mods need to be done to the loom?

Cheers, Eddie

[stonesie]

None, transfer the later management onto the early engine and see Ant for a slightly more spicy management chip

IIRC the biggest difference is the early management takes its engine speed and crank position from the flywheel, the later management uses a much more reliable trigger wheel on the front pulley and a sensor on one of the plug leads, with both engines next to each other it should be easy to transfer all the relevant bits over.


For the engine ID, on the inlet side near the engine mounting arm will be a flat area with the engine code stamped on it:-
25 6 E = early high compression
25 6 K = later low compression (K=Kat prepared)

[eddie124]

Hi stonesie,

the problem is the engine's already been put in there, and afaik, they just placed the engine/box and its ecu in place on the Touring. I'm going to have it collected later this week as the kid I got it from and the electrician can't figure out how to make it run, but he says he didn't keep any hardware from the original m20b20...

Can I get the loom there to accept the older engine (he's just confirmed it's from a late-85 325) with its own ecu and loom, or do I have to get a correct set of stuff for the Touring's year?

Cheers, Eddie