Replica Austin Seven Works OHC Single Seater Sports
Owner Sean Smedley
This beautiful replica of the works OHC single seater has been built by Sean Smedley
Photographs by Sean Smedley
Sean started this project in July 97. He started with the ‘A’ frame chassis, body supporting spaceframe, tubular front axle and an offset rear axle casing with nothing inside! His aim was to produce a copy of the works OHC single seater. Sean had seen one at the VSCC Prescott Hill Climb and thought what a fantastic little car...sort of a 2/3 scale ERA!
The engine has a 1932 crankcase, Phoenix 1.5" crankshaft, Renault 4 rods and pistons (the 58mm bore gives 805 cc). The engine has an aluminium head (with a 7.5 compression ratio) and a single 1.25" SU carburettor. If you look at the photographs, you will see the water flow is out of the radiator at the bottom, through a pump (you cannot see in the photographs), into the front of the block via the core plug hole, out of the back of the block, into the rear of the head and finally out of the top front of the head. All the interior water holes between the head and block are blanked off. This should result in efficient cooling.
The oil system is mounted on a bracket which takes the place of the starter motor (car is bump started). Its a full flow system with an adjustable pressure relief valve. Two oil feeds go to the engine, one to the front of the old gallery, the other to the "top hat" structure on the nose of the crankshaft. This "contains" two back to back oil seals. A third valve outlet dumps excess oil back into the crankcase where the mechanical fuel pump used to be.
The gearbox is a four speed synchro with close ratios, the constant mesh gears are modified to give 1, 1.22, 1.93 3.2 as overall ratios. This is a modification performed by Don Rawson in the UK. The clutch is operated by the hanging pedal bearing directly on the operating arm. It has extra springs and the flywheel is lightened. Brakes are Morris Minor with 100% flexible piping back to the master cylinder (a Landrover clutch cylinder). This flexible piping is sold by motorbike outlets and the easiest way to connect up hydraulic brakes.
Sean built the motor with a lot of advice from Tim Myall, a well known Austin 7 engine builder in the UK. Rod Yates built the aluminium body. Sean made a jig from chipboard for the difficult rear shape. Vertical sections at 4" intervals were measured from museum photos.
The project has moved on since the photographs shown here were taken. Sean fired the car up in March 2002 and successfully raced at the French vintage car races held at Montlhery in April 2002.
The Austin Seven Motoring Pages