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Moto Guzzi V8 1956-57
1956 GUZZI VEE-8. Variety is the spice of life—or so it's
said. Obviously the Guzzi people had heard of this when, in 1956, after racing
500 c.c. single-, twin- and four-cylinder machines, they revealed to a surprised
world their latest "500" with an eight-cylinder engine! These tiny cylinders,
with dimensions of 44 mm. bore and 41 mm. stroke (624 c.c.) were arranged in two
banks at 900 to each other; a gear train drove the double overhead camshafts.
Eight carburetters, 20 mm. bore, were tucked in between the banks. Separate
exhaust pipes were used, without megaphones.
The radiator for the watercooling system was mounted low down
in front of the crankcase, and coolant was circulated by a pump driven from the
timing case. Apart from its small dimensions the motor followed fairly
conventional practice internally, with the connecting-rods for each Vee-pair of
cylinders mounted side by side on one throw of the 1800 crankshaft. Plain
big-ends were used; main bearings were four roller and one (drive-side) ball.
The original design called for a six-speed gearbox, as a narrow power-band was
anticipated. But it was discovered that the motor would pull quite happily from
7,000 to its maximum of 12,000 r.p.m. At 12,000 r.p.m. it churned out 62 b.h.p.,
which permitted a maximum speed of over 160 m.p.h. to be reached on a 61:1 gear!
The model appeared in the Isle of Man in 1957 when Dickie Dale
eventually brought it home fourth, after having trouble en route. In fact, it is
doubtful if more than seven cylinders were working for most of the race, as
misfiring set in early and the machine smoked noticeably from one pipe
throughout the later stages.
What a pity that Guzzi withdrew from racing at the end of that season, by which
time the Vee-8 was producing 79-80 b.h.p. at the rear wheel.
SPECIFICATION
Engine: 90° Vee-eight 500 c.c. d.o.h.c; watercooled;
drive to camshafts by gear train. Ignition: battery and eight coils.
Transmission: gear primary drive to four-speed gearbox in unit with engine;
final drive by chain.
Frame: semi-duplex cradle with swinging-fork rear suspension; large diameter
top-tube used as oil reservoir.
Forks: leading link controlled by hydraulically damped spring units mounted
forward of the main fork members.
By, Murray Barnard
Few motorcycles have captured the public imagination as the
Moto Guzzi 500cc V8 race bike. This machine was an incredible work of genius by
Guiliano Carcano. Although never developed completely, racing only from 1955 to
1957 the Moto Guzzi V8 is still a technical marvel which has still to be
equalled.
Development was stalled when Moto Guzzi pulled out of GP racing in 1957along
with most of the other motorcycle manufacturers, German, Italian and British. In
it's day the V8 was able to achieve remarkable speeds for the technology of its
time, reaching 187 mph at the MIRA test track in France. Whist still under
development it was clocked at an incredible 178mph at the Belgian GP in 1957.
Producing 75 bhp at a then remarkable 12,500rpm the machine only weighed 135kg.
Pictures fail to convey the incredibly compact design of the V8. The Moto Guzzi
250 and 350 GP singles at that time were the slimmest, lightest machines on the
track yet the V8’s fairing for all it's added complexity, was only 30mm wider
than the factory 350 single. The small bore and stroke of 44mm X 42mm enabled
Carcano to keep the transverse mounted engine quite narrow.
The carburettors were specially designed for this engine by Dell'Orto. In early
engines, the two banks of 4 Dell'Orto carburettors were fed fuel by two large
float bowls mounted on the left-hand side of the engine, but this led to rough
running so later engines were fitted with custom made Dell'Ortos, each with
their own individual float bowl.
The V8’s development was plagued with trouble at first. The V8 was first ridden
at the 1954 Belgian Grand Prix by Aussie rider Ken Kavanagh but it soon suffered
a crankshaft failure. The bike didn’t appear again until 1956 when Kev again
rode the machine, this time at the Coppa d’Oro race. He soon retired with
bearing trouble. Bill Lomas and Kev Kavanagh rode V8s at the Dutch Grand Prix in
1956 and after making the fastest lap they both retired. And so the sad story
went on. Little things such as water hoses let the machine down.
Bill Lomas
Tests of the V8 continued with a revised machine at Monza, then Montlhery,
Oulton Park and Snetterton! In 1958 the V8 won its first race at Syracuse in
Sicily, although this was a non-championship race. Finally at Imola Dickie Dale
won a GP recording the fastest lap. Dickie went on to ride the V8 at the Golden
Jubilee TT at the Isle of man coming a poorly placed fourth Beaten by a MV and
two Gilera fours there was no reason to go on with such a complex machine. Guzzi
retired from racing at the end of the year and the fascinating V8 motorcycle
disappeared from the race circuit, never to be equalled, although Honda has
tried with the oval piston NR500 which was even less of a success and a 4
cylinder at that.
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