Hello
The changes in US and euro 113 fuel injected engines were very minor compared to other engines manufactured after 1975 in the US. In the US after 1975 major changes in compression and timing and emmissions caused manufacturers to make special engines castings and parts for the US market. The W113 engines were never equipped with a catalytic converter or had their compression lowered. In fact at the end of production the compression was still at 9.5 to 1 in the 280-SL, which was the highest of all the 113 cars. The 113's with their M130 engines, were produced up to 1971.
The carbureted Mercedes engines of these years did not burn as clean as the injected engines and starting in 1969, were loaded down with air pumps and many other emission items. The fuel injected 113 engines were more efficient and powerful and ran a little cleaner than the Mercedes carbureted cars during those years and were spared some of the other emission add-ons. The W113 engines had some changes made to engine timing and the injection pump after 1968. The camshaft was the biggest performance change in the US versus Euro engines.
If the valve cover is removed, an ID number is stamped on the firewall end of the camshaft. A mirror is needed to view it since it is on the flat end of the cam. Or you can also view the casting number on the side of the camshaft. The last two digits of this seven digit Mercedes part number is the ID number of the cam. The US emission cams were normally stamped 01, the euro were stamped #09 & # 02. I believe that some of the early USA 280-SL's 1968 and 1969 were delivered with the #09 cams also.
The ignition distributor with it's retard and advance feature is unique to the US emmission cars. The distributor and the timing relays that were added to the US engines are the most obvious USA emission features. Prior to 1969, the USA and Euro engines were nearly identical.
If you compare the 0-60mph (0-100kph) times in the Mercedes technical data books you will see that the times range from 9.0 seconds to 11.l seconds. Rear end ratio and transmission made the biggest difference not the engine type. Only ten kilometers per hour variation at top speed for all the models and all combinations!
Joe Alexander
Blacklick, Ohio
