Semi-Diesel Hot-Bulb engines
L. Gardner & Sons of Patricroft, Manchester are best known for their economical road transport diesels, many of which have passed into preservation during the post-war years.
Gardners also made a big range of other engines, some of which would have required some very specialised trucks to carry them to their destinations. In common with other
companies in the early 1900's, Gardners went into the hot-bulb engine market as a progression into the oil engine market. The following pictures are from a set which illustrate the 4-cylinder
hot-bulb semi-diesel engine very well.
The main lower crankcase casting with main bearings and oil pipes installed.
Gardners had their own large foundry site where all their castings were produced
ready for machining in the main factory machineshops.
Nice and clear picture of an assembled crankshaft. The balance weights were added after the crankshaft was machined from a single billet of metal.
Note the ring oil feeds for each big-end bearing, a practice which continued into the 1960's with some engines.
Section of the original cylinder head design with the early burners which were fitted to heat the hot-bulb before starting.
The burners were run off petroleum and compressed air, and were automatically turned off when the engine started.
A shot of the reversing mechanism of the engine, located at the end of the engine over the gearbox or clutch.
The engine could be
reversed easily from speed by simply winding the handwheel
from forward to reverse, all the fuel and timing adjustments being carried out
Line drawing of the Gardner fuel pump assembly.
I will put a description of the pump operation here at a later date.
A somewhat clearer version of the reversing and governor controls.
Later cylinder head with electric glow plug starting, replacing the older blow-lamp heating.
Worth mentioning the way the fuel nozzle was
rotated to vary with the engine loading.
Section of the flywheel, clutch and thrust bearing for the propellor shaft.
The complete engine with no stern equipment fitted.
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