Australian Road Rider — August 2017

NEWS FOR ROADRIDERS

A HEAD OF ITS TIME?

We all know BMW horizontally opposed engines as “Boxers”. But why?

G

lad you asked. Boxer engines got

their name because each pair of

pistons moves simultaneously in

and out rather than alternately, like

boxers showing they are ready to go into ba le

by touching their gloved fi sts against each

other before a fi ght.

Of course, they have become synonymous

with BMW for motorcycle applications, but

Boxer engines of up to eight cylinders have

proved highly successful in cars and continue

to be popular for powering light aircra.

Many years ago, Max Friz, BMW’s head

designer, reluctantly turned to motorcycle and

automobile engines to sustain the company.

Within four weeks, Friz designed the now-

legendary horizontally opposed twin-cylinder

engine known today as the Boxer engine.

The fi rst Boxer engine M2B15 was based on

a British Douglas design. The M2B15 proved

to be moderately successful but, with the

development of the fi rst light-alloy cylinder

head, a second more successful version of the

Boxer engine evolved. In 1923, the fi rst BMW

motorcycle, the R32, was produced. Using the

new aluminium alloy cylinder heads, Friz

designed a 486cc engine with 8.5hp and a top

speed of 60mph. The engine and gearbox

formed a single unit. The new engine featured

a recirculating wet-sump oiling system, which

was very advanced for 1923 as many motorcycle

manufacturers still used a total-loss oiling.

BMW used this type of recirculating oiling

system until 1969, showing the advanced

design of the times.

The R32 became the foundation for all

future Boxer-powered BMW motorcycles.

BMW oriented the B oxer engine with the

cylinder heads sticking out on each side for

cooling. Yep, it was all about cooling, folks.

Some reckon they are ugly; others swear by

them. Your thoughts?

12 | AUSTRALIAN ROAD RIDER

UPFRONT

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