M42 compatability

[lcgtrplr]

Hi am looking at a newer m42 for my 91 e30 318is as a replacement Are all of the m42 engines compatible or is there any components that will be different?...AC compressor etc  thanks

[DesktopDave]

I think all years of the M42 are pretty similar, except intake manifolds.  I've heard that the serpentine belt system can even be retrofitted as well.  The e30 never had knock sensors or OBD2 so your selection of engines is pretty good...any e30, early e36, '95 e36 Ti or Z3.

The M44 would bolt up but require an engine wiring harness & DME.  I'd assume EWS would be a problem without that silly RF key sensor ring, EWS brain & matching keys.

Someone else on the board will know for sure though.