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M117 engines 450
M117 engines 450

Mercedes-Benz used same engine numbers M117.982 (D-Jetronic) and M117.985 (K-Jetronic) to deliver different engine versions for Europe / standard, the USA (emission regulated) and low compression (NV= niederverdichtet) markets with lower fuel quality both in 450SL and 450SLC as well as with other numbers in W108 280 SE(L) 4.5 and W116 450SE . But in reality these are very different engines that vary in compression, power, torque, cam shaft and emission control a lot.

The following table tries to give an overview over 450SL and 450SLC engines. 90% of all 450SL were built with US engines, so don't be surprised to normally find them in all the 450SL reimported to Europe from the US. The 450 engine at first was only available in the US while Europe got the smaller 350 engine with a similar power. Only as of 1973 MB delivered a more powerful European 450 engine. Unfortunately it is really difficult to identify which kind of engine is built into a car. Neither cam shafts nor the absence of exhaust return valve or the presence of European Jetronic and ignition components can make you really sure about the version as everything could have been swapped. There is a white paint labeling on cylinder heads back side, but you can harldy read it, even if engine is out of compartment. You can see that EUR labeling on pictures below,, USA is hard to read. In doubt only a compression test can give such a hint.

Data 350 SL 4.5
/ 450 SL/C
350 SL 4.5
/ 450 SL/C
450 SL/C 450 SL/C 450 SL/C 450 SL/C 450 SL/C 450 SL/C 450 SLC lightweight
Country USA USA USA USA Standard NV Standard NV Experimental
Engine no.  M117.982 M117.982 M117.985 M117.985 M117.982 M117.982 M117.985 M117.985 M117.405-186
Injection D-Jetronic D-Jetronic K-Jetronic K-Jetronic D-Jetronic D-Jetronic K-Jetronic K-Jetronic K-Jetronic
Start of make 1971-02-01
SLC 1972-06-26
1973-08-24 Calif.
1974-08-01 USA
1975-09-01 Calif.
1975-11-21 USA
Sep 79 1972-06-26 1972-06-26 1975-11-21 1975-11-21  
Power DIN/SAE hp 190 180 180 160 225 210 217 200 282
  at rev/min 4750 4750 4750 4200 5000 4800 5000 4750 6000
Compression ratio 8 8 8 8 8,8 7,5 8,8 7,5  
Max. torque Nm 325 298 298 312 378 353 360 345 365
  at rev/min 3000 3000 3000 2500 3000 3500 3250 3000 3000-4500
Cam shaft no. left 52 56 00 06 56 56 00 00  
Cam shaft no. right 53 57 01 07 57 57 01 01  
Max speed km/h 198 198 198 179 215   210   245
Acceleration 0-100 km/h in s 10,5 10,5 10,5 11,7 8,8   9,3    
Acceleration 0-100 mls/h in s 29,5 29,5 29,5 35,0 22,6       14,0
Differential ratio 3,07 3,07 3,07 2,65 3,07 3,07 3,07 3,07  
MY 73 1972-06-26 Introduction 450 SL/C in Europe and worldwide, earlier only USA
USA MY 74 1973-08-24 California with exhaust return valve
USA MY 75 1974-08-01 all USA with exhaust return valve
USA MY 76 1975-09-01 K-Jet California
Worldwide 1975-11-21 K-Jet worldwide
USA MY80   K-Jet 160 hp

Compression ratio is done by different pistons. Main shaft is identical.

According to EPC cam shafts are changed more often than shown here.

Sources: Engelen, Wikipedia, EPC

M117 450 engine with EUR label
M117 450 engine with EUR label
M117 450 engine with USA label
M117 450 engine with USA label

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