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Reference in our July 4th issue to the Gosport & Fareham Omnibus Company's Provincial bus with its air-cooled diesel engine has now been followed by a visit to Fareham where The Transport Journal was able to see the vehicle, ride in it and talk to the man who brought it into being - H. Orme White, Director, Manager and Engineer of the Gosport & Fareham undertaking.

As previously stated the conversion has been made to a 10-year-old Guy Arab double-decker having a new fully fronted body built by Reading & Co Ltd of Portsmouth. Bodywork is generally orthodox with 56 seats provided, but there are variations to the front end, The distinctive radiator grille now standardised on full-front bodies in the Provincial fleet hinges back completely on the bus with the Air-cooled diesel to present a secondary shield In which is a sliding panel lined up with the engine blower.

At present the sliding panel is being adjusted from day to day to assess the ideal air input. The other unusual aspect of the bodywork - although it is in fact standard practice on Provincial buses - is the use of the area to the nearside of the cab as luggage space: the N/S door is marked "luggage compartment" and as many as 12 folding pushchairs have been carried in it.

The 6 cylinder Deutz Air-cooled Diesel (described later in this article) is rubber mounted at four points and no difficulty was experienced in fabricating the necessary brackets to suit both engine and chassis, although it was necessary to tilt the engine by some 10 degrees to position it the space available. As with most engines there was some judder to the unit on starting, slow tick over, and stopping but one simple rubber at the offside front mounting point has completely obviated this.

Considerable attention has been paid to engine insulation - both for heat and sound - and the engine compartment is lined with one and a half inch glass fibre, while additionally there is a quilted cover over the engine compartment. This has proved very successful: the engine is very quiet - certainly no noisier than a comparable water-cooled unit -while little or no heat is transferred to the driver's cab. Thoughts that it might be difficult to keep the engine operating temperature low enough have also proved wrong for, if anything, the temperature is on the low side. On the hot summer day at the beginning of July when we travelled in the bus the cab temperature was 80 degrees F and that of the engine 140 degrees F.

Vibration is also noticeably low. At engine idling speed, when vibration is often noticeable in the seats and stanchions, there was complete absence of movement: this may be accounted for by the Deutz engines comparatively high idling speed of 500 RPM. Fuel and oil consumption figures approximate closely to the fleet average.

The Deutz engine is the F6L 514 six-cylinder in-line model. Air cooling, which is the main interest of British operators, is effected by a large capacity fan on the offside (vee belt driven), with ducting to give a flow from starboard to port through cylinder fins. Cylinder barrels are separate units with detachable heads, the securing b9olts passing through the heads and into the crankcase. The barrels are spigotted top and bottom for location and made in cast iron, while heads are die-cast in light metal. Gas sealing is effected by rubber rings at the lower end and by a joint face at the top. Air and exhaust passages are on the same side to the head, opposite the injector and heater plug. Gudgeon pins are offset towards the exhaust side for smooth running. The drop-forged connecting rods are H section and the big ends are split diagonally: bearings are lead-bronze shell type.

Of high-grade steel, the crankshaft runs in seven steel-backed lead-bronze bearings. The camshaft and tappets are carried in the crankcase and light alloy push rods operate the overhead valves; eats and valve guides are renewable. Rocker arms on bronze bushes and an oil tight cover enclose the valve gear.

The thoroughness of German design is evidenced by several safety measures built into the engine. For example a temperature indicator is built into the cylinder head and this can be coupled to either an audible warning device or a shut down mechanism. Similar devices are operated by a simple spring mechanism attached to a the vee belt jockey wheel to warn of any belt breakage. Lubricant is force fed by a gear pump driven from the crankshaft, a secondary line feeding the camshaft and rockers. An oil cooler is also provided. Fuel injection pump is by Bosch and is gravity fed, while the engine incorporates a Deutz injection timing device and governor for idling and maximum speed.

Various fuels may be used in this engine, the normal one being gas oil, but the range includes brown coal fuel oil, tractor fuel, kerosene, and petrol/lubricating oil mixture in the ratio 90%-10%. One more unusual mixture is that of 99% motor spirit and 1% Kerobrisol, this latter substance raising the ignition quality and cetane number of light fuels.

It is too early to decide whether the air-cooled diesel engine will become widely accepted for British operation, but certainly the first results are promising. Soundproofing more than obviates any extra noise in operation and fuel consumption appears to be comparable with that of similarly sized water-cooled diesels. Due regard must be given to the fact that no radiator and attendant water cooling system is required; the complicated gaskets are eliminated; that the cooling air reached a temperature of 176 degrees Fahrenheit and can be used for saloon heating; and that buses with air cooled engines can be parked in the open in any weather, these factors must carry considerable weight in the minds or manufacturers and operators.

No of cylinders	6 in-line
Injection principle	Indirect :swirl chamber
Maximum torque	332 ft lb at 1,200 RPM
BHP	125 at 2,300 RPM
MEP	86.9 lb per square inch
Bore and stroke	4.125 inches X 5.5 inches
Compression ratio	17.8:1
Specific fuel consumption	.396 lb/bhp/hr at 1,1200 RPM
Starter	12 volt
Net weight	1430 lb