E30 318i M40 to M44 conversion
 

Hey guys,

A friend of mine's timing chain broke in her E30 318i and I was thinking about recommending an M44 to replace the M42 that came with her car. The M42 is plagued with issues involving the timing chain breaking. How hard would it be to replace the M42 + transmission with the M44 + transmission provided I have the wiring harnesses, DME, and EWS together?

As far as I understand, the motors almost fit together perfectly, but I'm sketchy on these motors. The transmission could be dismounted and connected to the current tranny, if needed too.

I would not go thru the trouble of doing an OBDII to OBDI swap for a 4 cylinder. There are TONS of little modifications you have to make. If you must have DOHC go for the M42.

Why would I have to do an OBDII to OBDI conversion? I thought that OBD was only required for Inspections and they would inspect it without OBD at all since it's made pre-OBDII.

I suspect it would work fairly well. The most difficult thing to get working would be the EWS. Did the E30s have this? Isn't there hardware in the steering column that's part of this system? That's the only thing I would worry about. If you have the whole M44 with all the associated sensors, etc. I think you'll be good. Don't forget the airbox and all the sensors there too. The DME will want those. You might also have difficulties with the ASC+T. I don't know if the E30 have the wheel-slip sensors. Good luck and keep us posted.

Are you sure it's an M40 engine? I didn't think that the M40 was available in the USA and it has a timing belt not a chain. USA 318i models had the M42 engine which is a twin cam 1.8L with a timing chain.

Converting from M40 to M42 in an E30 would be much easier than an M44.

I'm pretty sure, but not positive. It's whichever motor had the premature timing chain failure in 1991. Actually, it sounds like the M42 makes more sense now.

Well if it is a USA car then it won't be an M40 for sure so it must be an M42 and, as I said earlier, the M40 has a belt not a chain. M42's had a common problem with the profile gasket but I am not aware of premature timing chain failure as a common problem. (The two E30 318is's I have owned both have had 150,000+ miles on their original chains). However, the timing chain tensioner was changed in design and the part from the M44 is now the recommended replacement for the M42.

The M44 and M42 are very similar in specification except the M44 is 100cc larger. Power is almost the same and torque is up slightly but the peak occurs lower in the rev range. I would say that it wouldn't be worth the expense to install an M44 in an E30 due to large number of changes necessary. Fitting a second hand M42 would be the easiest and most cost effective option.

Alright, thanks for your advice guys. I've told her not to get the M44 because of these issues. Looks like she's gonna get a 318ti now! Maybe we'll have another forum member soon.