The Specifications
Engine R.A.C rating.....................12.8 hp
B.h.p at 2000 rpm.......................27.
Bore and stroke..........................72mm x 114.5mm
Total capacity...........................1861cc
Wheel-base..............................9ft 4inches
Track.......................................4ft 8inches (older models 4ft)
Full car length including grid.....13ft 6 inches
Full car width.............................5ft 6 inches
Body space..............................8ft 0 inches
Tyres.......................................4 3/4 inches for 20inch rim with medium pressure
Ground clearance.....................8 1/2 inches (216)mm
Weight of chassis........................16 cwt
...........................5 seat touring car........................22 cwt
...........................Saloon........................................24 cwt
.........................Petrol tank capacity......................8 gallons
General Gear Ratios
1st speed....................... 20 to 1
2nd speed...................... 12 to 1
3rd speed........................ 8 to 1
top speed .......................5.1 to 1
How to set the camshaft timing
The way to set up an Austin engine fitted with a chain driven camshaft is
as follows.
Turn the engine until the mark on the flywheel indicates that No1 piston is
at TDC
Next, turn the camshaft until the inlet valve of No1 cylinder is just commencing
to rise.. The two timing gears are now in the correct position for the chain
to be fitted .It will sometimes be found, however, that the chain will not
engage properly with the teeth on the timing wheels when they are in this
position In such case turn the camshaft back until the teeth engage,
remembering that the camshaft rotates in the same direction as the crankshaft,
and not in the opposite direction as with the Austin seven
In the case of the Austin Twelve, when the timing is correct, the TDC mark
on the flywheel, when the inlet valve commences to lift, mat come anywhere
between 3/8 of an inch before or after TDC.
Scource
Austin service journal