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www.leylandprincess.co.uk B-Series After the end
of World War II, Austin and Morris continued to rely on pre-war engines for
their mid-range family cars. Out of the two companies, it was Austin that
managed to introduce an entirely new engine for its A40 Devon model. This
engine displaced 1.2-litres (65.5mm x 88.9mm bore/stroke), produced 39bhp at
4300rpm and was an overhead valve design. Morris, on the other hand,
continued to rely on the side-valve solution for its engine, as used in the
Issigonis designed Morris-Cowley. By the time of
BMC's formation in 1952, this was still very much the engine situation, and
it meant that the company had a choice between the Austin A40 engine and the
1477cc Morris unit. Given the
relative merits of the two engines, and the Austin-biased management in the
new organisation, it comes as no surprise that the Austin unit was adopted as
the new engine to power all
of the company's cars in the mid-range. Logically
enough, it was subsequently dubbed the B-Series, and it proved to be
significant in BMC's history because its features defined the style for all
of BMC's later engines. Included in this list would be the location of its
electrical equipment and the induction/exhaust complex on opposite sides of
the engine block. Also, the pushrods passed through passages on the induction
side of thecylinder head in order to avoid the use of pressed-in tubes
passing across the plug cavity. The crankshaft had three main bearings and
the connecting rods were split diagonally. In 1954, the
first three-box BMC saloon was launched; the Austin Cambridge, which employed
the B-Series engine in 1.2-litre guise, as well as a newly-enlarged 1489cc
version. The uprated B was produced by a simple process of
"boring-out" to 73mm. The power output of this version of the
engine was 50bhp, which was produced at 4400rpm. This engine was also used in
the Morris Oxford series II and the MG ZA Magnette, although the MG was
treated to a twin-carburettor set-up, which boosted power to 60bhp at
4600rpm. It was with
the engineers at MG that the B-Series went through further development in
order to release more power - eventually resulting in the 68bhp version that
powered the 1956 MGA. In 1961, the
B-Series had been further evolved: the B's engine block was redesigned in
order to accomodate newly-siamesed bores, thus enabling the bore to be
increased to 76.2mm. This increased the capacity to 1622cc and it was
possible - with tuning - for it to produce 83bhp. This extra power was
produced at 5600rpm, and these higher rev limits were possible thanks to the
use of Vandervell VP3 in the main bearings. Among the other changes were
improved valves, pistons and rings. It was not until the following year that
a "cooking" version of the B found its way into the Farina
saloons... they made do with a more realistic 61bhp at 4500rpm. Further
development of the B-Series led to a 1798cc version of the engine, which - in
three-bearing form - first saw the light of day in the MGB. The bore centres
remained the same as the original 1.2-litre A40 Devon engine, but the bore
measurements grew out to 80.3mm. In time for the launch of the ADO17 in 1964,
the three-bearing crankshaft was replaced by a five-bearing item in the
interests of increased smoothness, and this new set-up resulted in a power
output of 84bhp (gross) at 5300rpm. Development continued as far as the
addition of twin-carburettors, a set-up developed with the help of Daniel
Richmond, which was used in the Austin and Morris 1800S versions. Such a
twin-carburettor model never found its way into the Princess, though the
Special Tuning department at BL offered a bolt on twin-carb accessory kit
through the dealer network for the Wedge, which resulted in a car that was
quicker than an MGB! By the early
1970s, it became clear that the B-Series needed to be replaced with a new
unit that would be able to meet with upcoming US emissions regulations. The
B-Series was by then, well established in 1800cc capacity alone, and was used
in the front wheel drive 1800 models as well as the rear wheel drive Marina
and MGB. Because a development programme to replace it never got far off the
ground, the engineers at Abingdon worked hard on an OHC version of the
engine, which would meet and exceed the forthcoming emissions regulations.
This was the nearest thing to a replacement in the pipeline, and when it became
clear that the ADO17's replacement would need a de-smogged engine, the new
car, which subsequently evolved into the Princess, was designed to use the
OHC version of the B-Series engine. Given that the
two engines were initially going to be physically very similar, the
development of the newer engine would not need to be accelerated to meet the
new car. And that led to the MG engine being adopted as the corporate
replacement for the B-Series, which resulted in further and wider ranging
changes. The result was the O-Series; an engine that started out as being
related to the B-Series, but became more of a case of the Irish hammer - two
new handles, three new heads, but the same hammer! The 1800
versions proved to be the most popular models in the 18/22 Princess range. Copyright © 2007. Keith
Adams Certain paragraphs added by Kevin Davis. Updated 7th May 2007. |
1800 versions
of the Wedge were the most popular, though Morris 1800 and Austin 1800 models
are extremely rare now. In fact there are also very few Princess 1800s around
now despite their popularity when new. |
