HomeMotor Car Exhibition at Olympia
Another completely new car exhibited is the 10 horsepower BSA.
This has an air cooled twin cylinder engine of the 90 degree V pattern, and the cylinder dimensions are 89.75mm bore by 85mm stroke.The body is designed to carry two adults, but there is room for a third in emergency, the front seat being 3ft 6in wide, and there is a dickey seat at the back. We propose to give further particulars of the mechanical features of this car in our next issue.
The 10 horsepower car built by the Birmingham Small Arms Company, to which we referred in our last issue, is a distinct departure as regards its mechanical features from this firm's standard practice. It also possesses originality as regards the design of the body. The great objection to the ordinary dickey seat - that in had weather its unfortunate occupants are left exposed - has been overcome in this case by a hood of ingenious design which can be extended to cover the dickey seat when necessary.
When the dickey seat is unoccupied, the hood is of the ordinary
two seater form, and with the side curtains provides complete protection from the
weather. Should the dickey seat be occupied, however, the extension of the hood
is only the work of a few minutes. There is also a fair amount of space for luggage
in the tail even when the dickey is occupied, while with the dickey seat unoccupied
the luggage space is very considerable, as, in addition to space inside the tail, the
flat sloping top is covered with ribbed aluminium and is adapted for use as a
luggage grid on which quite large articles can be carried.
With regard to the motive mechanism, there is nothing in the outer appearance of the car to give any suggestion that the mechanism differs from that of an ordinary car. The engine is placed under the usual bonnet, and not even the cylinder heads are exposed. The whole of the air for cooling purposes is taken in through the dummy radiator, and passes out partly through louvres in the bonnet sides and partly under the floor hoards. The engine is of the twin V pattern, with cylinders 89.75mm bore by 85mm stroke. Sectional views of the engine are given in Figs 14 and 15.
The cylinders are of cast iron in one piece with the heads. There is a
patented valve gear, whereby the radially inclined valves, which seat directly in the
spherical head of the cylinder, are operated by rode lying parallel to the axis of the
cylinder. The valves themselves are made of a new alloy produced by Wm. Jessop
and Sons'Limited, and are tulip shaped. The cylinder walls and head are thick to
provide ample conductivity, and thus prevent distortion due to unequal heat
conditions.The 
cooling fins are deep with roots of reasonable thickness, while the
fins on the cylinder heads are so disposed as to equalise the temperature all over,
and so prevent excessive temperatures in the neighbourhood of the exhaust valve
scat and pocket. It is claimed that the inclination of the valves makes the
combustion space of almost ideal form, so that the flow of heat to the walls from
the burning gases is as small as possible, while the turbulence of the charge is kept
at the maximum. The aluminium alloy pistons are full skirted, as opposed to the
'Slipper' type, so as to provide good dissipation of heat to the walls of the cylinder.
By the insertion of a small spring ring at each end, the hollow floating gudgeon
pins are prevented from moving axially and so scoring the cylinder walls. Both big
ends, of course, work on a common crank pin, each big end being provided with
a large diameter roller bearing. The crank shaft has balance weights, and is carried
by two hall bearings which are seated in cast iron housings and not direct in the
crank case, so that they cannot become loose in the aluminium.
At the rear end the crankshaft carries the flywheel in the usual way, while adjacent to the front bearing is the spur pinion which drives the half-time wheel on the cam shaft. The latter is mounted directly above the crank shaft, the cams themselves being inside the crank case, in the angle between the two cylinders. The four cams work direct on the mushroom ended tappets, which are prevented from rotating, and the tappets in turn operate the overhead valve rockers through the medium of long hall-ended push rods. Each overhead rocker is completely enclosed by telescopic tubes. The whole of the overhead valve gear is thus protected from dirt, and is lubricated automatically by oil mist sprayed up from the crank case through special grooves cut for the purpose in the tappet guides. Tappet adjustment is provided on the overhead rockers, and is immediately accessible by removing the rocker case lids.
The ML magneto is gear driven off the half-time wheel on the cam shaft, and is provided with a micrometer adjustment for setting the ignition timing. The magneto contact breaker faces forward and is thus very accessible. An oil sump holding sufficient oil for well over 200 miles' running is cast in one with the crank case. Oil is drawn from this through a large filter by a submerged gear pump driven by the crank shaft through spiral gears and a short vertical shaft. From the pump oil is forced under pressure up a pipe leading to the wall of the near-side cylinder, while small branch pipes cause jets of oil to impinge on the timing gears and the magneto drive gears. An oil spray is thus formed which effectually lubricates all hearings in the timing case. The off-side cylinder and piston are lubricated in the usual way by splash from the rotating crank shaft and big ends. Surplus oil from the crank case drains hack to the sump, while the sump itself is finned to ensure that the oil is kept at the correct temperature. An oil flow indicator is fitted in a convenient place to show whether or not the lubrication system is acting correctly when the engine is running.
The starting handle is carried in an extension of the aluminium casting which forms the timing case cover, and engages with a dog on the end of the cam shaft instead of the crank shaft. Thus the engine is geared up from the starting handle, a feature which makes it easy to 'swing' the engine at a good speed without undue effort. There is a special induction system, combined with the exhaust arrangements, which calls for attention. In this system a 'hot spot' is provided adjacent to the Zenith carburetter, which ensures vaporisation of the lowest grade fuels.
From the engine the power is transmitted through a double plate clutch of the cork insert type to a three speed and reverse gearbox of conventional design, see Fig 16.
This gearbox is bolted to the crank case, so as to form one unit with the engine.
The clutch is completely enclosed in the fly-wheel pit between the engine and
gearbox, but can be got at if necessary through an inspection door. The gear
change is operated by a centrally placed lever, mounted on a ball and socket joint
in the gearbox lid itself. It should be noted, however, that contrary to usual
practice, when a central gear change is employed, the hand brake lever is not
placed in the centre of the car, but is at the right hand side of the driver, where
it does not obstruct the seats and cannot be interfered with by the passenger.
From the gearbox the drive is taken to the rear axle by a tubular propeller shaft,
which is completely enclosed in a spherical headed torque tube. Inside the
spherical joint and completely enclosed by it is a ring universal joint, which is
automatically lubricated from the gearbox. This is the only universal joint on the
car.
The rear axle of the BSA car is of the built-up type, with a cast aluminium centre and steel axle tubes. It incorporates a Daimler-Lanchester worm gear, which is silent in action. Daimler-Lanchester worm gears have been a feature of Daimler and BSA cars for many years, but this new BSA car is the first light car in which such a rear axle specification has been included. A standard type of bevel differential gear is fitted, while both hand and foot brakes are of the internally expanding type, operating in drums of unusually large diameter on the rear wheels. The brakes are of the non-compensated type, operated by rods throughout, and are provided with means for instant adjustment by spring-locked wing nuts, situated in an accessible position. Another interesting feature of the brakes is that if it be desired to inspect the brake shoes it is only necessary to remove the detachable rear wheels, when the brake drums themselves can be pulled off by hand and the shoes with their operating mechanism exposed to view. This is an improvement on usual design which necessitates the wheel centres being pulled off the axle shafts before the brakes can be exposed, a job which, as most owner-drivers know, often requires special tools not available in the owner's garage.
The front axle is of the usual I section forged type, but the stub axle and swivel pin design is unusual, in that it is so arranged as to allow the swivel pin to be in the plane of the wheel. Thus no bending moment is caused on the swivel pins by the weight of the car or by road shocks, and, moreover, there is no tendency whatever for the wheels to be deflected by road obstructions. This feature greatly reduces the stress on the steering gear, and makes it possible to drive the car with the lightest touch on the steering wheel, even on bad roads, and in spite of the fact that the steering gear is not irreversible. The steering gear, front hubs, spring shackles, brake rockers, are fitted with Enots grease gun fittings. Quarter elliptical leaf springs are fitted front and rear. The foot accelerator pedal and ignition lever are on the steering column. An electric self-starter is fitted, and when the spark is fully retarded a special cam automatically opens the throttle to the correct starting position.
This has an air cooled twin cylinder engine of the 90 degree V pattern, and the cylinder dimensions are 89.75mm bore by 85mm stroke.The body is designed to carry two adults, but there is room for a third in emergency, the front seat being 3ft 6in wide, and there is a dickey seat at the back. We propose to give further particulars of the mechanical features of this car in our next issue.
The 10 horsepower car built by the Birmingham Small Arms Company, to which we referred in our last issue, is a distinct departure as regards its mechanical features from this firm's standard practice. It also possesses originality as regards the design of the body. The great objection to the ordinary dickey seat - that in had weather its unfortunate occupants are left exposed - has been overcome in this case by a hood of ingenious design which can be extended to cover the dickey seat when necessary.
When the dickey seat is unoccupied, the hood is of the ordinary
two seater form, and with the side curtains provides complete protection from the
weather. Should the dickey seat be occupied, however, the extension of the hood
is only the work of a few minutes. There is also a fair amount of space for luggage
in the tail even when the dickey is occupied, while with the dickey seat unoccupied
the luggage space is very considerable, as, in addition to space inside the tail, the
flat sloping top is covered with ribbed aluminium and is adapted for use as a
luggage grid on which quite large articles can be carried.
With regard to the motive mechanism, there is nothing in the outer appearance of the car to give any suggestion that the mechanism differs from that of an ordinary car. The engine is placed under the usual bonnet, and not even the cylinder heads are exposed. The whole of the air for cooling purposes is taken in through the dummy radiator, and passes out partly through louvres in the bonnet sides and partly under the floor hoards. The engine is of the twin V pattern, with cylinders 89.75mm bore by 85mm stroke. Sectional views of the engine are given in Figs 14 and 15.
The cylinders are of cast iron in one piece with the heads. There is a
patented valve gear, whereby the radially inclined valves, which seat directly in the
spherical head of the cylinder, are operated by rode lying parallel to the axis of the
cylinder. The valves themselves are made of a new alloy produced by Wm. Jessop
and Sons'Limited, and are tulip shaped. The cylinder walls and head are thick to
provide ample conductivity, and thus prevent distortion due to unequal heat
conditions.The cooling fins are deep with roots of reasonable thickness, while the
fins on the cylinder heads are so disposed as to equalise the temperature all over,
and so prevent excessive temperatures in the neighbourhood of the exhaust valve
scat and pocket. It is claimed that the inclination of the valves makes the
combustion space of almost ideal form, so that the flow of heat to the walls from
the burning gases is as small as possible, while the turbulence of the charge is kept
at the maximum. The aluminium alloy pistons are full skirted, as opposed to the
'Slipper' type, so as to provide good dissipation of heat to the walls of the cylinder.
By the insertion of a small spring ring at each end, the hollow floating gudgeon
pins are prevented from moving axially and so scoring the cylinder walls. Both big
ends, of course, work on a common crank pin, each big end being provided with
a large diameter roller bearing. The crank shaft has balance weights, and is carried
by two hall bearings which are seated in cast iron housings and not direct in the
crank case, so that they cannot become loose in the aluminium.
At the rear end the crankshaft carries the flywheel in the usual way, while adjacent to the front bearing is the spur pinion which drives the half-time wheel on the cam shaft. The latter is mounted directly above the crank shaft, the cams themselves being inside the crank case, in the angle between the two cylinders. The four cams work direct on the mushroom ended tappets, which are prevented from rotating, and the tappets in turn operate the overhead valve rockers through the medium of long hall-ended push rods. Each overhead rocker is completely enclosed by telescopic tubes. The whole of the overhead valve gear is thus protected from dirt, and is lubricated automatically by oil mist sprayed up from the crank case through special grooves cut for the purpose in the tappet guides. Tappet adjustment is provided on the overhead rockers, and is immediately accessible by removing the rocker case lids.
The ML magneto is gear driven off the half-time wheel on the cam shaft, and is provided with a micrometer adjustment for setting the ignition timing. The magneto contact breaker faces forward and is thus very accessible. An oil sump holding sufficient oil for well over 200 miles' running is cast in one with the crank case. Oil is drawn from this through a large filter by a submerged gear pump driven by the crank shaft through spiral gears and a short vertical shaft. From the pump oil is forced under pressure up a pipe leading to the wall of the near-side cylinder, while small branch pipes cause jets of oil to impinge on the timing gears and the magneto drive gears. An oil spray is thus formed which effectually lubricates all hearings in the timing case. The off-side cylinder and piston are lubricated in the usual way by splash from the rotating crank shaft and big ends. Surplus oil from the crank case drains hack to the sump, while the sump itself is finned to ensure that the oil is kept at the correct temperature. An oil flow indicator is fitted in a convenient place to show whether or not the lubrication system is acting correctly when the engine is running.
The starting handle is carried in an extension of the aluminium casting which forms the timing case cover, and engages with a dog on the end of the cam shaft instead of the crank shaft. Thus the engine is geared up from the starting handle, a feature which makes it easy to 'swing' the engine at a good speed without undue effort. There is a special induction system, combined with the exhaust arrangements, which calls for attention. In this system a 'hot spot' is provided adjacent to the Zenith carburetter, which ensures vaporisation of the lowest grade fuels.
From the engine the power is transmitted through a double plate clutch of the cork insert type to a three speed and reverse gearbox of conventional design, see Fig 16.
This gearbox is bolted to the crank case, so as to form one unit with the engine.
The clutch is completely enclosed in the fly-wheel pit between the engine and
gearbox, but can be got at if necessary through an inspection door. The gear
change is operated by a centrally placed lever, mounted on a ball and socket joint
in the gearbox lid itself. It should be noted, however, that contrary to usual
practice, when a central gear change is employed, the hand brake lever is not
placed in the centre of the car, but is at the right hand side of the driver, where
it does not obstruct the seats and cannot be interfered with by the passenger.
From the gearbox the drive is taken to the rear axle by a tubular propeller shaft,
which is completely enclosed in a spherical headed torque tube. Inside the
spherical joint and completely enclosed by it is a ring universal joint, which is
automatically lubricated from the gearbox. This is the only universal joint on the
car.
The rear axle of the BSA car is of the built-up type, with a cast aluminium centre and steel axle tubes. It incorporates a Daimler-Lanchester worm gear, which is silent in action. Daimler-Lanchester worm gears have been a feature of Daimler and BSA cars for many years, but this new BSA car is the first light car in which such a rear axle specification has been included. A standard type of bevel differential gear is fitted, while both hand and foot brakes are of the internally expanding type, operating in drums of unusually large diameter on the rear wheels. The brakes are of the non-compensated type, operated by rods throughout, and are provided with means for instant adjustment by spring-locked wing nuts, situated in an accessible position. Another interesting feature of the brakes is that if it be desired to inspect the brake shoes it is only necessary to remove the detachable rear wheels, when the brake drums themselves can be pulled off by hand and the shoes with their operating mechanism exposed to view. This is an improvement on usual design which necessitates the wheel centres being pulled off the axle shafts before the brakes can be exposed, a job which, as most owner-drivers know, often requires special tools not available in the owner's garage.
The front axle is of the usual I section forged type, but the stub axle and swivel pin design is unusual, in that it is so arranged as to allow the swivel pin to be in the plane of the wheel. Thus no bending moment is caused on the swivel pins by the weight of the car or by road shocks, and, moreover, there is no tendency whatever for the wheels to be deflected by road obstructions. This feature greatly reduces the stress on the steering gear, and makes it possible to drive the car with the lightest touch on the steering wheel, even on bad roads, and in spite of the fact that the steering gear is not irreversible. The steering gear, front hubs, spring shackles, brake rockers, are fitted with Enots grease gun fittings. Quarter elliptical leaf springs are fitted front and rear. The foot accelerator pedal and ignition lever are on the steering column. An electric self-starter is fitted, and when the spark is fully retarded a special cam automatically opens the throttle to the correct starting position.
   
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