Beardmore-Halford-Pullinger
The B.H.P. engine
WWI The authorities brought Frank Halford back from France to develop the 160 h.p. Beardmore engine (which had been based on a water-cooled six-cylinder Austro-Daimler engine) with a view to designing a more powerful unit, which he did with Arrol-Johnston in Dumfries, where he worked with T. C. Pullinger.
In the B.H.P. Halford departed from the accepted practice of using a single large inlet exhaust valve, instead using two small exhaust valves and a single large inlet valve per cylinder.
1917 The outcome was the B.H.P. (Beardmore-Halford-Pullinger) engine — a 230 h.p. (170 kW) vertical six-in-line water-cooled engine embodying cast-iron cylinder heads, steel cylinder liners, and sheet-steel water jackets.
This engine was further developed by Siddeley-Deasy for aircraft use. They changed the cylinder heads and water jackets to aluminium and the name to Puma. They made over 6,000 Pumas.[1]