SOME SPECIAL BENTLEYS
Mr. McKenzie, of McKenzie’s Garages Ltd., 1, Bridge Place, Belgrave Road, London, S.W.1, was with the RollsRoyce Company before the War, engaged in the experimental and competition departments. In 1924 he came into close contact with 3-litre Bentley cars owned by the sons of Rolls-Royce clients, and later he opened his present premises behind Victoria Station for the purpose of specialising in Bentley and RollsRoyce sales, service and special construction.
At the end of last month we invited ourselves to view these extensive premises and found much of direct interest to MoToR SPORT readers.
The first car to catch our eye was a special 1932 8-litre Bentley modified for a friend of the late Sir Henry Birkin and fitted with. a Corsica four-seater open body designed by McKenzie expressly to meet this client’s requirements. This is a truly imposing motor-car. The radiator and scuttle have been lowered five inches, mainly to improve driving visibility, and this has imparted to the car extremely fine and sporting lines. The radiator was cut towards the top and all the shutters shortened to suit, but it Is impossible to discern the joints. A new honeycomb is used, 18 lb. lighter than the old block, and of modern style with baffled tubes, which results in 33* per cent. improvement in cooling. The thermostat maintains the water temperature at 85(C., the shutters operating at once if the heat rises or falls either way. Owing to the lowered header tank the thermostat had to be moved over to the near side, and a neat link-action was incorporated to work the shutters. The elektron dash was also cut down and welded, a remarkable piece of work, which has enabled all the components mounted thereon to go back In practically their original positions. Owing to the difficulty of correctly synchronising coil and magneto ignition, and in the interests of easy starting and low-speed pulling, Mr. McKenzie has fitted twin Delco coil units. The carburetters are the usual twin S.U. instruments, with black-painted bodies and the additional Bentley slowrunning miniature carburetter. Fuel feed is now by two Autopulse electric pumps set beneath the forward carburetter at frame level, because the lowered
position of the autovac only ensures a reliable feed up to 70 m.p.h. On the other hand, the autovac is retained as a reserve, and a switch behind the instrument-board enables the pumps to be cut out completely when desired. Movement of a big tap beneath the bonnet then brings in the autovac. Wheu the pumps are in use a small tap relieves the autovac suction valves, which would otherwise suffer. The fuel-pipes unite via a clever four-branch union, and are polished in keeping with the high finish of the whole engine.
The crankshaft has been carefully balanced, and the pistons are of McKenzie’s own design, weighing 2 lb. 1 oz., a saving of 6 oz. They are of “Y” alloy, heat-treated, made on special dies by Specialoid Ltd.
The compression ratio has been increased from 5.1 to 1 to 5.6 to 1. Experiments have shown that with the standard exhaust system 28 b.h.p. is absorbed at 3,000 r.p.m., and consequently a 3 inch tail-pipe replaces the former 2 inch pipe. A cut-out is fitted, controlled by a small lever in the centre of the driving compartment, reminiscent of a remote gearlever. Incidentally, Mr. McKenzie has had extremely good results from Servais straight-through silencers. The clutch of this 8-litre is lined with a special friction material that gives 334 per cent. greater adhesion than formerly, without recourse to heavier clutch springs, so that clutch weakness is obviated and the pedal pressure is astonishingly light. The right-hand gear-lever has a neat fume-excluding gaiter and the right-hand brake-lever has been arranged to lie horizontally, in a very convenient position. The footbrakes have a wing-nut adjustment by the gear-lever and can be adjusted while the car is in motion. The rear drums have the single-wide shoes, which wear extremely well, operated by the hand-lever, all brakes being applied by foot via a Dewandre vacuum-servo, which is the standard 8-litre practice. 19″x7″ wheels replace 21″, resulting in a one-inch lowering of the whole car. They are shod with Dunlop 90 Fort covers, which, unlike certain other tyres, do not endow the steering with unfortunate characteristics. The rear-axle ratio is now 3.3 to 1, obtained by making up new hypoid bevels. Andro telecontrol shock-absorbers are fitted to both axles. The former saloon body has been replaced by the McKenziedesigned Corsica four-seater, with cutaway front doors, high rear panels and a raised-surface dropped waist-line. The scuttle has raised wind deflectors, to which the single-pane screen conforms. The latter folds flat for speed work, deflected slightly downwards to improve streamlining, and having an automatically-broken plug-in contact for the central wiper box. In either raised or folded position its rests on rubber pads, and has Lancegaye safety glass. The hood disappears into a roomy well which allows the material to hang clear of the sticks. The specially arranged side-screens store in a zip-fastened pocket in the front of this well, which is covered by a nonshrinkable cover. In the tail is a well to take two specially-shaped suit-cases five inches deep. The Hobson Telegauge has been dropped to give a smooth unobstructed floor area. The lid also folds back when it is required to carry additional luggage, and the strap staples have been disposed to render such accommodation easy. Bosch built-in direction indicators are fitted, with a 15 sec. time lag for the automatic cancelling. Upholstery is in leather, and the separate front seats have Leveroll adjustment. Their cushions consist of semi-inflated air cushions covered with 1* inch swandown, which Mr. McKenzie finds combines the maximum of comfort with the minimum of rolling. The fully equipped instrument board has large black-dialled and very unobtrusive rev-counter and speedometer mounted side by side directly before the driver. The Blume’ steering wheel has the finger-grip rim, suited to heavy driving gloves, and a specially large boss to eliminate trouble with cracked spokes, the latter being of limited flexibility. The chassis is the shortwheelbase type, unshortened, the actual wheelbase being 12 ft. Tool-boxes are fitted under the floor and beneath the rear seat. The equipment includes Ace inbuilt number-plates, incorporating twin rear lights, stop and reversing lights. The wings and running boards are shapely without pretence to modernity, the dynamo mounting beneath the radiator is standard, and a dumb-iron apron is fitted. The engine rums up to 4,000 r.p.m., and the maximum speed as the car stands is 110 m.p.h. The attention to