M42 swapped Z3 1.8

dimiras

Dedicated Member
Joined
Oct 3, 2019
Points
43
Location
Azores, Portugal
Model of Z
z3 1.8 M42 swap
One year ago I got a 1996 Z3 with the M43 1.8 engine with almost 160k km on the clock, the car was Imported from germany to Portugal (S.Miguel Azores) in 2007. When I test drove it looked fine and cared after, drived fine and I only noticed some cosmetic blemishes so I bought it. The car passed MOT with no issues the day I bought it (July 2018).
Here is a photo of it the week I bought it:

One week later the problems started, the clutch started acting up and I had to replace the slave cylinder.
I also noticed that no matter how hard I pushed the car the temperature was always on Cold, so I ordered a new thermostat and flushed the cooling system because the last owner used tap water :mad:. After discovering that he used tap water I no longer trusted what we told me about the maintenance of the car so ordered new oil, new filters (fuel, engine and K&N air filter), new spark plugs, new water pump, new belt and rollers, new coolant hoses and flanges and replaced them all.

Here are some photos of the old fuel filter (production date 02.02.1996), like the last owner told me he only used genuine bmw parts in this car, the only problem is that these parts are there from factory =)).


I also found this:



The new thermostat solved the temperature problem and I kept a look for the coolant level and it was losing some coolant after some days driving (this was my daily at the time), I kept adding coolant thinking it was air in the system and then found a leak on one of the heat exchange hoses and fixed the leak. The car continued losing collant so i kept it topped up and gave up on it for some time (later I found that it was leaking from the back of the head.

After some time driving the car everyday I was driving and a loud noise came from the back of the car (whine), got to a service center and the diff was leaking fluid and there was no more fluid in it, the service center topped it up so I could go home and park it on the garage waiting for the diff repair kit to arrive. Some weeks later I rebuilt the diff at home and the car was running again.At least I found that the car has an LSD. I'm not finding pictures of the process so I will add them later.

To be continued ...
 
Last edited:

dimiras

Dedicated Member
Joined
Oct 3, 2019
Points
43
Location
Azores, Portugal
Model of Z
z3 1.8 M42 swap
So
Used the car for some more weeks and then it started getting hard to start and when it started a cloud of white smoke was getting out of the exhaust, a blown head gasket i tought, tested the head for warpage and it was fine so i tought the head gasket was just corroded from being used with tap water and doing only 1000km per year for the last 6 years (MOT km history).
Head gasket, bolts and seals ordered and I replaced the head gasket home, got the car running and still white smoke from the exhaust, I tought it was remnants of coolant that where still on the exhaust , but after a week of driving I was still losing coolant. Got the head off again and sent it to the machine shop to be tested, they found a huge crack between the exhaust valve and intake valve of cyclinder 3.
Now my options were buy a used Head, buy a remanufactured head or replace the engine with a known working one. I decided to put in a 1994 M42b18 from a 318is Coupe.
The engine was installed with all new sealsm, the intake heater hoses were deleted and the engine loom and the ecu from the M43 where maintained so I bought an M44 throttlebody with the later Idle control valve.
The engine started first time and then I did a remap to the M43 ECU in order to adapt it to the injectors and powerband of the new engine.
Here are some photos:




Now after a year of owning the car I have it running properly so the next mods that I have in mind are painting the valve cover and intake manifold black, improve the brakes, suspension bushes and do a plug and play Coil On Plug Convesion using pencil coils from later BMWs.
I'm already running adjustable Koni Sports with H&R lowering springs so I think I am good at that department.
Also when swapping the engine I noticed the Xbrace was not installed so I ordered one and Installed it (What a difference).

That's all for now tell me what you think.
 

dimiras

Dedicated Member
Joined
Oct 3, 2019
Points
43
Location
Azores, Portugal
Model of Z
z3 1.8 M42 swap
Weekend Updates!
Replaced the front control arm bushes.
The rubber from the old ones was so bad that it separated from the lolipop when I touched it, again they seemed to be original from when the car was produced. To remove the rubber from the control arm I cut a slot in the bushing to make it easier to remove from the control arm.



Also painted the upper manifold and throttle body.

 

dimiras

Dedicated Member
Joined
Oct 3, 2019
Points
43
Location
Azores, Portugal
Model of Z
z3 1.8 M42 swap
This weekend I finally finished my Coil on Plug conversion using the pencil coils present on the latest s54 engines and some e90.
Had to do a convertion harness to adapt the stock engine harness to the new coils.


And here is the final result:

I now need to make a cover to keep the oem look.

If someone is interested in doing the same I can help with the part numbers needed for the different plugs and the schematic or even create a tutorial.
 

Jack Ratt

Zorg Expert (I)
Supporter
British Zeds
The West Country
Joined
Dec 3, 2013
Points
200
Location
TRURO, CORNWALL
Model of Z
2.8i AUTO and 2.8i MANUAL
Good work Dimiras :beer
 

jayroll

Newbie
Joined
Mar 17, 2020
Points
4
Location
Finland
Model of Z
M44 1.9 Automatic
If someone is interested in doing the same I can help with the part numbers needed for the different plugs and the schematic or even create a tutorial.
Very nice thread! You've really had challenges with the car, but the end result is great. I would at least be interested about the details of the conversion, even though I've got a M44.
 

dimiras

Dedicated Member
Joined
Oct 3, 2019
Points
43
Location
Azores, Portugal
Model of Z
z3 1.8 M42 swap
The M44 uses the same round plug as my harness so you can do the same conversion, if you happen to go that route let me know so I can help you
 

dimiras

Dedicated Member
Joined
Oct 3, 2019
Points
43
Location
Azores, Portugal
Model of Z
z3 1.8 M42 swap
New Mod - cold air intake using the stock airbox.

3d printed a 76mm intake to replace the fog light:
image4.jpeg

and an adapter for the airbox:


DIfference on the airbox inlet size:
image2.jpeg


Then I have a flexible 76mm hose connecting the 2 parts.
The car seems the to be breathing better and the engine noise is more pronounced.
 

Attachments

Top