Mercedes-Benz M103 engine

The Mercedes-Benz M103 was a 15-degree, straight-6 crossflow cylinder head automobile in production from 1984 to 1997. It is a single overhead cam design with 2 valves per cylinder. The M103 was replaced by the M104 starting in 1989. This engine received several updates over the years of production, one of the updates was a change from a "heart shaped" to a "HEMI" spherical combustion chamber.

Specifications

The only mechanical differences from the M103 3.0 L to the M103 2.6 L were the smaller bore and intake valves, with a slightly different airbox. The CIS-E components between 2.6 and 3.0 variants are all shared for any given model year with the exception of the ECU making engine swaps from 2.6 to 3.0 virtually bolt-in.

Data accuracy

The M 102 and M 103 engine family has a common piston stroke of 80.25 mm. As only one decimal place is usually given, a large number of publications are in circulation with the incomplete specification of 80.2 mm. This applies in particular to more recent publications after production was discontinued. As a result, the inaccurate figures of 2,597 cc instead of the actual 2,599 cc for the 2.6 l engine and 2,960 cc instead of 2,962 cc for the 3.0 l engine have become established.