BMW M337

The BMW M337 is a straight-6 OHV petrol engine installed at a slanted angle which was produced in three variants (M337/1, M337/2 and M337/3) from 1952-1958. Built to power BMW's first new car after World War II, the M337 engine was a replacement for the BMW M78.

BMW M337
BMW 501- the first car to use the M337
Overview
Production	1952-1958
Layout
Configuration	Straight-6
Displacement	2.0–2.1 L (122–128 cu in)
Cylinder block material	Cast iron
Cylinder head material	Cast iron
Valvetrain	OHV
Combustion
Fuel type	Petrol
Chronology
Predecessor	BMW M78

Design

Compared with its M78 predecessor, the M337 features a revised cylinder head, a new inlet manifold and a reinforced crankshaft with bigger, more modern bearings.^{[1]: 88 [2]} As per the M78, the M337 has an iron engine block, an iron cylinder head and overhead valves with two valves per cylinder.^[3]: 46

Versions

Model	Displacement	Power	Torque	Year
M337/1	1,971 cc (120.3 cu in)	48 kW (65 PS; 64 hp) at 4,400 rpm	129 N⋅m (95 lb⋅ft) at 2,000 rpm	1952-1954
M337/2		54 kW (73 PS; 72 hp) at 4,400 rpm	130 N⋅m (96 lb⋅ft) at 2,500 rpm	1954-1955
M337/3	2,077 cc (126.7 cu in)		135 N⋅m (100 lb⋅ft) at 2,500 rpm	1955-1958

M337/1

The first version of the M337 engine has a displacement of 120.3 cu in (1,971 cc). It produces 48 kW (65 PS) at 4,400 rpm and 129 N⋅m (95 lb⋅ft) at 2,000 rpm.^[4]

Applications:

• 1952-1954 501

M337/2

In 1954, a revised engine was released which produced 54 kW (73 PS) at 4,400 rpm and 130 N⋅m (96 lb⋅ft) at 2,500 rpm.^{[1][4][3]: 48} The compression ratio for this engine is 6.8:1.

Applications:

• 1954-1955 501A
• 1954-1955 501B

M337/3

The final version of the M337 had an increase in bore of 2 mm (0.079 in), which increased displacement to 2,077 cc (126.7 cu in). The compression ratio was also increased to 7.0:1. Despite these changes the M337/3 produced no more power than the previous version. However torque increased to 135 N⋅m (100 lb⋅ft) at 2,500 rpm.^{[1]: 92 [4]}

Applications:

• 1955-1958 501/3