Difference between Euro and USA M117 4.5L engines.

Hi Volker,
I seem to recall that you have a 107 with Euro 4.5L engine.

There is a lady in New Zealand that has a Euro 74 350slc. Someone apparently swapped in an M117 4.L engine. However, they left the 350slc ECU and MPS in place. The car does not run very well! So she needs to find suitable ECU and MPS for the engine.

So question is - How would we determine whether or not she has a Euro or USA M117? The ECU/MPS part numbers are different. Engine number is 11798222022800.

Are the engines mechanically different - stroke, compression etc? I am away from home and don't have my reference info.

Any help appreciated.

Hi Graham,

actually M117 Standard and M117 US and M117 NV (Niederverdichtet = low compression) are 3 different engines. While we have a separate engine no. for NV, Standard and US version share the same engine nos.

That makes life difficult to differentiate. Neither cam shaft nos nor D-Jetronic or K-Jetronic injection components are a safe way to differntiate as they might have been swapped. What is different: Pistons and head plus ignition and injection components. So the only way to really know is compression. Or exhaust recirculation measurements which only US engines have.

I have written a German article on the 450 engine . Maybe that helps. You can see compression rate of 8.8:1, 8:1 and 7.5:1 . So if you have a leaking Standard version, you will also not be able to notice the difference. It is stupid that MB did not create 2 different engine nos.

EDIT: I forgot that I have also done it in EN: English article on 450 engine M117 .

PS: Since January, 2nd I have also taken over the biggest German forum on MB 107 SL /SLC, named Sternzeit-107.de (startime-107) . Currently I modernize it and it will also have an English speaking forum for the 107.

Thanks Volker,
I wondered if the the '22' in the engine number might help in determining which engine she has. The first '2' indicates engine was intended for a Right Hand Drive car. This would rule out European and US cars. What we don't know, is if engines with the 8.8:1 compression ratio M117 were built for Japan, South Africa, UK and other RHD countries.. This car was imported with a M116 engine, but the source of the engine is unknown.

Do you think the German Classic center might have a data base that would allow us to determine which M117 engine this is? I suppose we should just ask.

Finally, the lady is running out of money! A few options come up:
- leave M116 ECU/MPS in place and try and adjust mixture using MPS so that car does not run rich as it does now (It has the blue 036 injectors)
- install lower capacity yellow injectors (if they can be found used) or equivalent and again adjust MPS.
- install USA MPS and ECU and see how it runs (lean?) adjust if need be.

It is an unusual situation.

Interested in your new 107 site - My German is very limited, so look forward to the English version. Mind you, Chrome does automatic translations, so I will have a look.

PS: I will send her the link to your M117/4.5 page.

Hi Graham,

well a left hand could very well be European! O do you consider England, Wales, Scotland and Northern Ireland non-Eurpean? Well, one might wonder these days...

However a righr-hand engine M117.982 or M117.985 engine should always be a Standard engine. US versions were only delivered to US and CAN and they were always left-hand cars. But for sure she needs to swap ECU, ignition distributor, injectors and MAP sensor. Tell her to log in here, we might find a deal. But first she should be sure which exact components are installed.

When I lived in UK, Europe was on other side of the channel

I sent an email to MBUSA Classic center to see if they have an engine database.

Owner is in New Zealand, so assuming RHD, motor could have come from Japan, South Africa or other Asian countries or even UK. You are saying that all of those would have the 'standard' 8.8:1 compression M117?

Problem she will have, is that unless someone would swap her M116 ECU/MPS for a Euro M117 ECU/MPS, she would looking at quite a lot of money for the parts, even with a good deal

Hi Graham,

yes I mean that all RHD engines should be Standard engines.

If she finds someone to swap those parts (don't forget injector and ignition distributor?) in NZ that would be great. Otherwise shipping is already expensive.

G´day mates,


I´ll be Down Under X-mas 2018 (!) for some gliding, sailing and other stuff (XXXX).
So I can offer my shipping-services from QLD to NZ if required If there is any chance for me to hop over (e.g. accomodation?), I´d be happy to deliver things personally

Best regards,

Markus

If she finds someone to swap those parts (don't forget injector and ignition distributor?) in NZ that would be great. Otherwise shipping is already expensive.

The engine has the blue Bosch 036 injectors. Don't know about the distributor.. If it is different from a 4.5L USA or 3.5L Euro distributor, perhaps that is another way of confirming it is the 8.8:1 engine?

Is the vacuum advance/retard system different for the 4.5L euro vs the 3.5L euro? Different advance curve? Hopefully the distributor is the one that came with the engine.and it has been adapted properly to the original vacuum system.

An owner in Australia has a 73/74 4.5L euro parts car and is checking if he has the needed parts.

Hi Graham,
yes also iggnition distributors are different. You find correct one in attachment A of my compendium.

Looks like both 4.5 & 3.5 had retard & advance in 1974. But just how car is set up is another thing! Timing could be another thing that is off. Hard to be helpful at a distance and it doesn't seem they can get much help in New Zealand.
MBUSA Classic could not tell me which engine it was from engine number! But I suspect that being RHD engine, it must be a Euro.

Hi Graham,

yes also ignition timing is different. And I am not surprised that MB USA cannot tell you what kind of engine it is.

Hi Graham,
hi Volker

aren't the piston bottoms of the USA and Europe M117 engines different?

Then a quick insight through the spark-plug-hole using a endoscope-camera would help to identify the engine.

'Obelix' will know the differences between the engines ... maybe I remember the differences were once listed in the sternzeit-107.

Regards
Norbert

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.