Dorman Introduce Air-cooled Diesels
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ALTHOUGH rt developed specifically for use in construction equipment such as loaders and diggers as an alternative to auto
motive.type watercooled engines, a new range of four-stroke
air cooled diesel engines which has been developed by W. H. Dorman and Co. Ltd., of Stafford, may have possible application in commercial vehicles in the future. Known as the DA series there are at present two units—a fourand a six-cylinder in-line—but a V8 is to be added shortly.
Maximum continuous ratings of the engines are: 4DA four-cylinder, 64 b.h.p., 6DA six-cylinder, 95 b.h.p., and 8DA eight-cylinder, 125 b.h.p.—all at 2,500 r.p.m. These ratings increase by 10 per cent for intermittent use, making them 70.4, 104.5 and 137-5 b.h.p. respectively. If the engines were installed in vehicles these latter outputs would be the lowest ratings that could be expected. Engine capacities are 4-154 litres (253 Cu. in.) for the four-cylinder, 6.23 litres (380 cu. in.) for the six-cylinder and the V8 (which will be double the capacity of the fourcylinder) will be an 8-3-litre (506-6 cu. in.) engine. The engines have common bore and stroke sizes of 105 mm. (4-134 in.) and 120 mm. (4-724 in.) respectively and the weight given for the 40A is 825 lb. and for the 6DA 1,050 lb, No figure is given for the 8DA.
The new Dorman engines are basicath of conventional design and the finnei cast-iron cylinders are bolted to the tot of the crankcase with their skirts extend ing down into the crankcase to add to thi strength. Individual cylinders can IN removed complete with their pistons -am connecting rods for maintenance Cylinders are cast in aluminium alloy am the four cylinder head studs for eacl also bolt the cylinder barrel to the crank case.
As with the other series of these engines made by Dorman, common corn ponents are used so far as possible including cylinder barrels and heads pistons and con rods and all bearings Oil, fuel and air filtration equipment i of large capacity and the air cooling provided by an axial-flow fan, belt drivel from the front of the crankshaft. A pressed-steel duct provides even distribu non of the air along the engine and at oil cooler is mounted in the side of thi duct,