E30 M44??

[Jmorganix]

Has anyone yanked out the std M42 system in the E30 and replaced it with an E36 M42 system or an E36 M44 system?  What is the good, the bad and the ugly of doing it?

For that matter, has anyone ever fed an M44 from an e36 with an M42 harness/ecu?

Intake issues?  Harness issues?  Tell me whatcha know!

Jenn Morgan

[bmwman91]

An M44 swap would require it to be converted to OBD-I. That is expensive and a LOT of work. You might as well just run a stand-alone engine management system at that point.

The M44 did have a better timing chain guide system (no stupid little idler sprocket), and you can retrofit the timing case from one of those to the M42. Just make sure to use the M44 oil pump gears, and you'll need to make up a bracket to hold the crank position sensor.

The M44 head actually uses a more mechanically efficient valve actuation system (less friction) than the M42, so that is one advantage. People do tend to say that the M44 has a weaker crank since it is cast and only has 4 counter-weights versus the M42's being forged and having 8 counter-weights.

The M44 is advantageous in that it uses a MAF and it has the DISA intake manifold, which can help balance out the power band. It might be tricky to get DISA working well with a stand-alone, but it is certainly possible. I am not aware of anyone that has done the swap since the cost and amount of work would probably drive almost anyone to just swap in an M/S5x engine.

[benz-tech]

It appears you either go full M44 or Full M42, with a few hybrid exceptions. The M44 head will not work with the M42 Fuel injection since the cam sensors are different and in a different timing position, plus there is only one coolant temp sensor and its also different--all according to Metric Mechanics.
You could run the M44 crank/rods/pistons in the M42 block, with an overbore obviously. It may require removing the internal timing wheel, not sure but someone here or on R3v did that.
I will be running a full M44 setup including its Motronic, close-ratio trans and a taller axle to match.
A few other MM tidbits as well:
E30 intake manifolds flow better in the top end than the variable E36 stuff. M44 valve train is good to around 8K rpm with the right cams and springs.
That's all I know, and most of it is learned from MM since I called them for advice.
What I will learn in the following months I will share as well in a build thread

[HaNasich]

Has anyone yanked out the std M42 system in the E30 and replaced it with an E36 M42 system or an E36 M44 system?  What is the good, the bad and the ugly of doing it?

For that matter, has anyone ever fed an M44 from an e36 with an M42 harness/ecu?

Intake issues?  Harness issues?  Tell me whatcha know!

Jenn Morgan

Hi Jean,
in my E30 there's an E36 M42 engine, installed with E30 M42 engine management.
you can search and see my installation thread back from over three years now.

M44 and M42 engine mgmt are very different and adopting will take a lot of hassle, it will be easier to go with 3rd party mgmt (MS / MOTEC) and get better results.