Engine Autopsy
The elegantly simple Villiers 8E – achieving 50mph from just 197cc
The Villiers 8E – as found in all the best Bond Minicar MKCS.
Bond's post-war Minicars were intelligent minimal designs. They both predated and outlasted the bubble car craze, continuing to develop all the way up to 1966.
All were powered by two-stroke Villiers engines, mostly tiny single-cylinder units.
[A] CHAIN CASES The two large ovoid cast aluminium items are the inner (above) and outer (below) chain cases. They fix to the lower nearside part of the engine and gearbox assembly, with the clutch mechanism concealed inside the larger end, towards the rear. The small seal in the centre of the inner case is made of felt in engines of this age and had a tendency to dribble as it grew old. Villiers was an early adopter of modern lip-type rubber seals.
[B] CYLINDERHEAD The cylinderhead’s four mounting stud holes are clearly visible, as is the small hole for the cylinder decompression valve (shown on the right, above the old pink Lodge spark plug). This device allows the engine to be turned over with no compression before it’s started. This draws in petrol/oil/air mixture to lubricate the bearings and piston rings, and to facilitate quick starting when the valve is closed.
[C] CYLINDER BARREL The finned barrel is one of the few cast iron items in this featherweight aluminium alloy engine. The left side here is the front when mounted in a Bond Minicar. The exhaust pipe fixes directly onto the exhaust port, curving back to the nearside of the front wheel. The tiny variable-jet carburettor is an S25 model, made in-house by Villiers.
[D] CRANKCASE The crankcase halves are paired at the factory – look for matching numbers and letters on the underside of both pieces. Each half features two of the four studs used to mount the cylinder. The right-hand half (as seen here) has two long studs that fit through the transmission casing.
[E] GEARBOX Villiers made its own gearboxes, too – but only for motorcycle use. A Bond customer who wanted their Mark C to go backwards paid extra for an Albion gearbox with three speeds plus reverse.
[F] CHAIN, COVERS AND LEVERS
The chain connects the 23-tooth crankshaft sprocket (below it) to the clutch drive sprocket (opposite page). The clutch then passes drive on to the gearbox. To the left of the chain is the clutch outer dust cover. Above it lie the little clutch lever, the large kickstart lever and its return spring, and the stubby Bond-specific gearlever. The company had its own foundries and was self-reliant for every aspect of its engine and gearbox production, the only exceptions being bearings, seals and chains. By 1955, the Villiers name had appeared on two million industrial engines and one million motorcycle engines, with factories in Australia, France, Sweden and Spain churning them out under licence.
The Bond’s engine was mounted ahead of the car's front wheel. It pivoted with the wheel on an ingenious steering mechanism and drove it by chain via its three-speed gearbox.
[G] PISTON This is a standard 59mm piston from the 197cc 8E engine. One popular Villiers mod involves boring out 8E barrels to 63mm to take the larger piston from the 1H engine, which shares the same gudgeon pin height. This gives 225cc and a boost in torque.
[H] MAGNETO This assembly lives on the offside of the crankcase. It provides ignition and generates current. The crankshaft passes through it and turns the flywheel, which contains six magnets that cause the magneto coils to create current as they whizz past.
[I] FLYWHEEL A poorly-magnetised flywheel may still have enough attraction to stick to a metal bench but can cause running faults and starting difficulties. It’s possible to re-invigorate the magnets quickly and cheaply, often returning an engine to good behaviour.
[J] CRANK ASSEMBLY Villiers crank assemblies are famously well-made: rotating a crank in its two roller main bearings rarely reveals more than 0.0005in of movement away from true. The little end has a plain bearing. The big end has 48 rollers that bear directly on the crank pin and a casehardened hole in the con-rod. A rebuild involves pressing the assembly apart [K] CLUTCH FRICTION PLATES The drive sprocket takes the chain drive from the sprocket on the end of the crankshaft. To the right of that is the outer plate. The cork linings can cause trouble by burning out or expanding when hot and causing clutch drag.
[L] CLUTCH HUB ASSEMBLY
The clutch hub (upper right) mounts an intermediate steel plate and the outer plate on the six studs in its centre. These studs also mount the springs and fixing bolts that push the plates together and force the corks to grip the steel plates and the hub.
[M] PUSHRODS These two rather modest-looking items work together to separate the clutch plates. The long pushrod passes through the transmission and is actuated by the little clutch lever on the opposite page. The shorter one fixes into the clutch hub and acts directly to release the hub’s grip on the cork linings.