So how interchangeable are M104's then ???

[poormansporsche]

So got my sights on a nice cheap W202 C280 M104 and its got dead high mileage and I was thinking of instead of changing the head gasket just bunging in a lower mileage M104 3.2 - is it a straight swap like the ole M103's or is there much more involved. I know the 300 24v is different but whats the differences between the 2.8 and 3.2's

any thoughts appreciated

regards

brett

 

[RBYCC]

Brett

Mechanically it should be a straight swap, with potential difference in the transmission being early or later version.
Just make sure you use the electronics and engine wire harness from the donor vehicle.

Ed a.

 

[poormansporsche]

Thanks, was hoping the loom from the 280 would be reusuable as they are less prone to degradation than the 320 for some reason. So its not quite as simple as the m103 2.6 to 3.0 , unbolt engine plug in new one, swap ecu?

 

[RBYCC]

Thanks, was hoping the loom from the 280 would be reusuable as they are less prone to degradation than the 320 for some reason. So its not quite as simple as the m103 2.6 to 3.0 , unbolt engine plug in new one, swap ecu?

Just compare the looms and if interchangeable use the later model.

Many of the 94-96 320 looms have already been changed out.
Usually the problems are visible by stripping back the loom cover to see if there is insulation breakdown.
You can also do a point to point test with a VOM to find open circuit or high resistance in the wiring.

Do use the ECU from the donor vehicle to avoid any running problems.

Check to see if the the accessories are in the same location ( alternator, air pump, etc )..they should be close.

M103 swaps are a bit easier as they have minimal electronics to deal with

 

[bolide]

Is the throttle body the same on 280 and 320?

Nick Froome

 

[BillyW124]

...need to speak to the king of the unfinished!

 

[poormansporsche]

Billy, I expected my guru to be along by now

 

[BillyW124]

^ Probably too busy tarting up my M104!!! lol

 

[carat 3.6]

Sorry I'm late guys, somebody left this m104 in my workshop that takes up all my time lately.

As Ed mentioned the 3.2 engine is a direct swap for the 2.8, all the accessories are in the same places and you can re-use the 2.8 loom. The only problem that you may have is the ecu.

Depending on which year and gearbox the c280 has, limits which cars the donnor ecu can come from. If the c280 is an early car with a 4 speed box, the ecu can come from a w124. If you have a later car with a 5 speed box, you need to check which type of flywheel pick up it is using. If you have the old type with the 3 segments the ecu can come from a w124 again, but if you have the later type with the 62 teeth around the flexplate, you may need a w210 ecu.