1927 Amilcar C6
- Zahl der Sitze2
1927 Amilcar C6 Voiturette
Chassis no. 11032
Engine no. 90032
The C6 offered here, chassis number '11032', was a complete car when discovered by a Swiss journalist, Mr Heinz-Ulrich Wiesselmann, in East Berlin. Together with a spare chassis, '11023', the Amilcar was eventually smuggled out bit by bit into Switzerland. Both were purchased by a Mr and Mrs Frost of Florida, USA, who restored '11032' and sold the spare chassis '11023' to Desmond Peacock in the UK. '11023' was later rebuilt as a complete car and featured in The Automobile (January 1997 edition).
Maurice Frost ran '11032' for some time as a road car having fitted an accumulator box and starter motor. After some years the engine block cracked and a repair proved impossible, so Frost sold the Amilcar to a small motor museum. '11032' was later purchased from the museum by a British motor dealer, Mr Dan Margulies, who sold it on to a German client called Zinkle. Mr Zinkle delivered the car to Tomkins Engineering in Essex for rebuilding, and a subsequent deal involved Tomkins taking the Amilcar into stock. Bob Graves purchased the partially rebuilt car from Tomkins in 1982.
This Amilcar C6 was purchased as a complete car with matching part numbers except for the rear axle. Amilcar manufactured cars from kits of components, all stamped with the same number as the engine, though the chassis were never stamped during the 1920s. A serial number comprising the engine number with the first two digits substituted for '11' would then be allocated to each completed car. However, this C6's obviously very original body had no trace of any number, so it must obviously have been on a plaque. This car would have been '11032'.
This chassis has the engine number stamped on the dumb-irons but its lettering is different from all other stampings and was probably done for customs purposes to facilitate crossing boarders. The front axle assembly is stamped and the entire original assembly of stub axles, track rods and steering arms is in place. The steering box is original and correctly numbered. The radiator shell is original but the matrix has been renewed using the original honeycomb.
Plated '90032', the damaged engine was beyond use. New iron castings were commissioned to replace the original block and cylinder head, and were made by Grainger & Worrall Ltd, suppliers of iron castings to Cosworth. At the same time the opportunity was taken to provide an outlet for a modern full-flow oil filter. Many original components were used in the rebuilt engine: camshafts, magneto, water pump, timing gears, etc. The remanufactured engine is in a sense more 'original' than before, as machining has been done accurately to conform to the original Amilcar drawings, unlike the often sub-standard factory castings.
Cylinder head gasket failure was a common problem with these Amilcar engines, and Bob Graves's solution was to commission special seals that fit into concentric slots machined in the block around each cylinder. The new cylinder head casting, thicker in crucial areas, was machined to take modern 10mm spark plugs. Machining was carried out on the jig used for the very first Cosworth DFV heads. Fixing thread sizes were changed wherever it was thought they would improve reliability. Later cylinder head castings were thicker under the inlet ports, resulting in a stronger structure and superior port shape. Improvements were made to the oil and water pumps, and the clutch relined with a modern material, the latter necessitating a thicker pressure plate and stronger springs.
The gearbox and torque tube are correctly numbered but the gearbox casing was cracked and attempts at welding were aborted because of its porosity. A new casing was cast from the original in LM25 aluminium alloy, and the lengthy standard gear lever replaced with a remote linkage.
The original body has been retained and looks very good externally but is in fact full of filler, while its steel frame is deeply rusted. In a letter on file, Bob Graves remarks that C6 bodies were obviously hand built when the cars were ordered, as he had never seen two identical shapes. The current body was made from templates of the original. Construction is based on steel angle frame exactly as the original. The oil tank, normally carried between the front dumb-irons, has been moved to the engine bay firewall.
The brake back plates (the front ones are used to reinforce the steering arms) have been replaced because, like all C6 aluminium castings, they are highly suspect. Those fitted currently are replicas in heat-treated LM25.
The front dampers are built to Amilcar pattern but are of larger diameter and have additional friction plates. The rears are 1920s Rotoflex concealed behind the body because they were considered somewhat ugly. Road springs are the originals complete with the French maker's name. The rear ones are 'keyed' together, an Amilcar patent to supposedly provide lateral stability. Additional location is provided by a Panhard rod.
The rear axle carries the number '90016'. That is the number of the engine in the other C6 referred to above, which has this car's original axle, stamped '90032'. These axles were obviously interchanged while in the ownership of Mr and Mrs Frost in the USA.
Although just about acceptable when the car was purchased, the brakes quickly revealed their shortcomings and were progressively upgraded by Bob, their development taking a number of years. A mechanical balance bar has been installed to make the rear brakes more effective; some of the cables have been replaced with rods; and the front brakes have been converted to twin-leading-shoe operation.
In another letter on file, Bob states that the only power output enhancement on this car is the use of a standard Amilcar exhaust camshaft in the inlet position plus using steel tubes in the inlet ports to reduce their diameter and thus increase gas velocity and fuel atomisation. While satisfactory for running on petrol, the stock induction pipe was found quite unsuitable for alcohol fuel. Bob fitted a single feed from the supercharger to a primary pipe, feeding in two places into a secondary pipe, which in turn feeds the individual inlet ports. Experimentation revealed that alternative inlet and exhaust systems gave significant power increases but their use would have involved altering the bodywork and thus was rejected. Modifications to the fuel system included a new custom-made mechanical air pump and a smaller-capacity tank.
One of the more surprising discoveries was that the standard rev counter lagged well behind the crankshaft - blipping the engine to an indicated 4,000rpm actually revved the motor to 7,000! Bob cured this problem by using a modern Stack digital rev counter disguised with an Amilcar-style dial and bezel.
Bob estimated that manufacturing a C6 engine from scratch took 2,500 hours, and given the amount of care and attention to detail that this seems to have involved, that figure may well have been an underestimate. The development history of his Amilcars is recorded in detail in a fascinating 17-page document on file (perusal highly recommended). The highest power output quoted therein is 150bhp at the crankshaft, and the Graves Amilcar C6s are recognised as being the fastest in existence, dramatically quicker than the works cars were in period.
'11032' was raced extensively by Bob Graves in VSCC events and is pictured competing at Silverstone in 1994 and 1998, and the Brooklands Sprint in '98. The car is offered for sale by the Graves family and comes with a copy of the VSCC 'Buff Form'.