325 Engine into 318IS

[P_VIDDY]

After managing to break to m42 engines within a year i am now considering dropping a 2.5 in my 318is. what needs replacing?

engine, gear box, exhaust and shorter prop shaft????

How much work is involved?

any help appreciated

[E30Mark]

ECU, engine wiring loom, AFM bracket, suspension springs & insurance!

[P_VIDDY]

sein as it is a 318is with the stiffer suspension would the suspension not be able to take the extra weight?

[E30Mark]

The 4 and 6 pot cars normally have different springs... haven't a clue how it might handle with the extra weight.

[Dan318-is]

The fron springs need to be changed or uprated to 325i ones. Youl also need a new differential; recommended is 3.64 for early lumps and 3.91 for early lumps; i wonder what an early lump would be like with a 4.10 diff

[jmc330i]

what needs replacing?

engine, gear box, exhaust and shorter prop shaft????

All the above plus ECU, engine loom etc as Mark said and the Rad/hoses etc. Provided you get a 6pot with the complete loom still attached, it will just plug in to the socket up by the fusebox. Run a new starter cable from the battery to the starter ( ) and connect the earths up and that should be the wiring done.

As well as the AFM and water header tank brackets, you may also need to sort something for the single coil on the 6pot - Im not sure how different the coil pack mounting is on the iS shell.

The iS should have the Mtech suspension fitted, so only the front springs should need changing for 6pot springs.

You will also need to change the diff - I think the iS has a small case 4.10, but you would need the larger case 3.64 or 3.91 and ideally an LSD

[Geeman]

Would have to be at least 325i Sport springs to match the rears.

[jaistanley]

Rears are the same I beleive.

I am planning to do the same at some point, the only difference being that my donor engine is an auto so I've bought a manual gearbox to fit (and apparently I need to wire some sort of short for the Auto box so it'll start??).

Good luck my friend, it's a pretty easy conversion. Let me know of any problems along the way so I can avoid them!

I have a medium case 4.1 LSD in my 318iS and I plan to use that with a non-sport gearbox (cos I want to spend very little and it's what I have). I shall go on the hunt for a 3.64 I think as I want to drive it to work on the motorway. The 4.1 will be fun for a while and I can sell it for decent money when finished (it's rare as hems teeth in the UK, came from an American M3).

Jai

[micktdel]

Jai,

How much are you after for the 4.1 LSD. I am looking to get one for my Is.

[Brianmoooore]

(and apparently I need to wire some sort of short for the Auto box so it'll start??)

Find a couple of single connectors above the glovebox, both with black/yellow wires going into them. Unplug and remove the starter inhibit loom and relay, and plug the two connectors still in the glovebox together.

[m-dtech]

you might need to change the propshaft ?

[Brianmoooore]

You will need to change the prpshaft!

[jaistanley]

I had to get a new propshaft but it came with the gearbox..

The diff isn't for sale just yet, I need the car still and I've provisionally agreed to hold it for Dan318is (unless someone offered me a right b0ll0ck for it) when I do take it off.

Jai

[sharkEr]

What about an oil cooler? I'm about to do the same thing, have both engines out of the cars and I'm going to leave the 4.1 diff.

[Morat]

Until an expert tells you different, I think you'll be OK without an oil cooler. The turbo boys disconnect them to make room for their intercoolers and say that modern engine oil can handle the temps without the dedicated cooler.
OTOH, that must mean that there are some spare oil coolers around that you could have for not much cash

[Brianmoooore]

M20B20 manages without an oil cooler, and oils have come a long way since the M20 was designed.
M50B25 doesn't have one either, so the M20B25 should be fine as well.