We have recently made a test of the latest Alta aluminium cylinder head on an Austin Seven. The head, which increases the compression-ratio of a standard engine from 5.0-to-1 to 6.2-to-1, using a normal-thickness gasket, has specially-formed combustion chambers and 14-mm. plugs above the exhaust valves. We fitted the Alta head to a 1934 engine which had had no attention, apart front removing the carbon from the piston-crowns, since it was thoroughly overhauled 11,000 miles ago. As the car concerned is a saloon, no performance figures have been taken, but the Alta head gives a very evident increase in liveliness and improves acceleration, so that driving in the thickest London traffic is something of a joy—it is surprising how many cars a four-speed Austin Seven will beat from the traffic-lights if it is handled intelligently. The Alta head has been in use for only about 350 miles but in this distance the gasket has shown no sign of blowing, although the old one was retained when the head was fitted. On Pool petrol there is no “pinking,” the engine retaining its characteristic freedom from this malady, and the conversion has proved in every way worthwhile and satisfactory. We note, however, that a ¼-in. bolt has to be used in place of a 5/16-in. bolt to retain the water-outlet pipe, which renders the task of making a water-tight joint at this point, a delicate one.
These Alta heads not only improve performance but are appreciably lighter than the standard cast-iron head; they would appear to be a “must” for racing to the 750 Club Formula. The price is £5 10s. each and the makers are the Alta Car & Engineering Co., Ltd., Fullers Way, Kingston By-Pass, Surbiton, Surrey. We fitted a new set of 14-mm. plugs with the head and, using a Runbaken “Oil-Coil,” a new Lucas battery and Castrol XL oil in the sump, starting from cold is very certain, with a minimum of choke. The next component we intend to test on this engine is a Wico-Pavy vertical magneto.