BMW M70


The BMW M70 is a SOHC V12 petrol engine, which was BMW's first production V12 and was produced from 1987 to 1996.
The BMW S70/2 engine, largely unrelated to the M70 and S70B56 engines, is a DOHC V12 petrol engine, which powered the 1993 to 1998 McLaren F1.

Design

The M70's design is similar to that of two 2.5 L M20 straight-six engines joined at a 60 degree angle, due to the following features: single overhead camshaft valvetrain, bore spacing of, bore of, stroke of, and a compression ratio of 8.8:1.
The M70 has the following differences with the M20 engine:
The M70 has two Motronic 1.7 ECUs. To provide redundancy, the M70 also has two fuel pumps, fuel rails, distributors, mass air flow sensors, crankshaft position sensors, coolant temperature sensors and throttle bodies.
Some M70 engines are fitted with two alternators. The second alternator is smaller and is used to charge an auxiliary battery and power equipment in the rear passenger compartment, such as a telephone, fax machine, wine cooler, independent climate control and power sun shields.

Versions

Applications:

S70B56

The first engine to use the S70 name is a variant of the M70 engine fitted only to the E31 850CSi. With 1,510 units produced, this is the lowest production BMW engine to date.
Three prototype dual overhead camshaft S70 engines were constructed, prior to the decision to not produce an E31 M8 model.
Applications:
The S70/2, while sharing the same 12 cylinder layout, bore spacing and design principle as the S70B56, is essentially a new design with the heads based on the European market S50, and thus featuring 4 valves per cylinder and variable valve timing and individual throttle bodies. A dry sump oiling system is used. The weight of the S70/2, plus ancillaries and full exhaust, is.
Applications:
The S70/3 is a racing engine based on the S70/2.
Applications