Difference between Euro and USA M117 4.5L engines.

Hi Norbert,

I am sure the difference would be obvious if the two pistons were compared on the work bench. But unless you really knew what to look for, I suspect endoscope wouldn't show much.

As it is, the engine number indicates it was originally in a RHD car and it has the 4.5 M117 Euro distributor installed, so we are pretty sure now that the engine is a 4.5 M117 Std/Euro.

The lady who owns the car (badged 350slc) was getting very frustrated in attempts to get it running properly. Not proven yet, but problem is more than likely that someone did not transfer the 4.5L MPS and ECU when the engine was transferred..

Regards

Graham

Hi Graham,

and please do not forget the engine wiring harness. I once saw a 450 SL US where I was surprised to find a 4 pin connector on the 5 pin throttle switch. It turned out to be a 350SL harness. That does not fit at all ! Signals from T.C: are then completely wrong.

Good point on harness! Just another possible complication!

Our NA 350/450SLs have the 5 pin throttle sensor plug. Did not know that the 1974 Euro 350sl did not have the full load contact.

No idea what the mechanic who did the engine swap did about harness. We know he did not change the ECU/MPS , but what did he do about the harness??

I will suggest they check how many pins on Throttle sensor and the sensor plug. It should have 5 if it matches engine (part 0 280 120 015)

Thanks

Hi Graham,

It has nothing to do with Europe versus NA. EVERY 350 engine has a 4 pin throttle switch. They do not have full-load contact. They use full-load diaphragm in MAP sensor. ANd please do not consider the 350SL 4.5 a 350 SL. It is a 450SL with a wrong naming.

The only 350 engines in NA were in early W111 and W109. R/C 107 never had a 350 engine M116 in NA. Grey imports might have - but than they are European models anyhow. With nice bumpers and better performance.

Addtl: Contact sequence on 350 and 450 throttle switch is different. So connecting a 350 harness to a 450 throttle switch (no matter whether left or right position then) will not work.

It has nothing to do with Europe versus NA. EVERY 350 engine has a 4 pin throttle switch. They do not have full-load contact. They use full-load diaphragm in MAP sensor. ANd please do not consider the 350SL 4.5 a 350 SL. It is a 450SL with a wrong naming.

I think we have got off subject We have established which engine the New Zealand lady has and what parts she needs to match the engine. Used parts have been located. It's up to her now to decide what to do.