The A-70 featured a cast aluminium crankcase in two sections, a two piece forged chrome-nickel steel crankshaft, and one piece master connecting rod. All rods were H section. The crankshaft was mounted on ball and roller bearings.
The pistons were unribbed cast aluminium in composite steel and aluminium cylinder assemblies. The heads were screwed and shrunk to steel barrels. The valves were tulip, tungsten inake and CNS exhaust.
All accessory drives except pump cross shaft were on plain bearings with full pressure lubrication. The rocker arms were on ball bearings.
There was no rotary induction system, but a double branch manifold feeding a horseshoe header. The lubrication system elibinated all internal and external piping.
The engine could be installed in the mounting ring without removal of any accessories.
Standard equipment was the exhaust nose ring and piping complete, nose cowling, air heater and cleaner assemblies, priming pump and fittings, ignition switch, and tool kit.
Accessories available at extra cost were any starter (including Heywood) using standard SAE mounting cylinders drilled for Heywood fittings, any generator with SAE flange, any fuel pump with SAE flange, and propeller hub.
Type: 7 cylinder air cooled radial
Dept of Commerce Approved Certificate
Rating: 165 hp at 2000 rpm
Displacement: 544 cu.in
Compression ratio: 5.4-1
Bore: 4 5/8 in
Stroke: 4 5/8 in
Length: 39 in
Diameter: 41 3/4 in
Weight: 430 lb
Fuel consumption: not more than .55 lb/hp/hr
Oil consumption: not more than .035 lb/hp/hr
Lubrication: Pressure and scavenger gear pumps, 75 lb/sq.in
Ignition: 2 Scintilla magneto
Spark plugs: 2 per cylinder B.G.