I've got a 1990 420SEL with an engine that's getting a bit tired at 217k miles, it needs new valve stem seals, new timing chain and a few other bits and pieces. I've also got (sat on the garage floor), an M117 5.0 from a 1990 500SE (I'm in the uk).

I know it will physically fit no problem, but are the electronics between the two engines the same? Can I just drop the 5.0 engine in and will it work with the 420ECU/Ignition modules etc?

Cheers, Martin

__________________
1990 420SEL 217k Miles
1975 Chevy K10 400ci SBC power!
1995 Jeep Cherokee 4.0 Limited
1997 Suzuki GSXR750 SRAD
1989 Kawasaki GT550G4

the ignition module shouldn't care. There might be some slight difference to any built-in advance behavior, but I doubt it. The FI system shouldn't care either, as long as the components are basically the same. Can you account for all the wires and vacuum lines on the two motors?

-CTH

__________________
- cth350@gmail.com
http://www.111lakeside.com/