Fuel efficiency isn't a new concept, despite what automakers would have you believe these days. (Though it must seem like a new concept to some automakers who snoozed away the last decade selling heavily ornamented light trucks only to be jarred awake by $100-per-barrel crude oil prices.)
Post-war microcar builders counted among their strongest selling points an ability to wring four dozen or more miles out of a gallon of gasoline--a given in war-torn Europe, but a quality treasured strictly by cheapskates and novelty seekers in the U.S.
The inexpensive, fun-to-drive Berkeley sports cars, built by a travel-trailer manufacturer in Great Britain, were claimed to be capable of 60 mpg, thanks to a series of motorcycle engines under their hoods. The last and most powerful of these engines was the Royal Enfield 692cc twin, an air-cooled, four-stroke engine used in Royal Enfield's Super Meteor.
The 692 was an overhead-valve, pushrod engine that used a 70mm bore and 90mm stroke with 7.25:1 compression to make 40hp. The Enfield was a dry-sump design with the oil tank integral with the crankcase. The crankshaft was a cast one-piece unit, and the pistons were made of aluminum alloy.
The excellent fuel economy could be due in part to the single Amal carburetor listed in the car's original specs, but the Berkeley pictured here, belonging to Jamie Pfeifer of Santa Barbara, California, uses a pair of Amals and probably has considerably more top-end power over a stocker.
The Enfields put power to the front wheels with a chain and sprockets through a multi-plate Albion clutch (with cable actuation) and a four-speed Albion gearbox with a 13.7:1 first gear, an 8.62:1 2nd, a 5.95:1 third, a 4.31:1 fourth and a 14.05:1 reverse.
The little cars used a 12-volt electrical system with a Lucas generator. Since motorcycle engines rely on gravity to supply the fuel and have no provision for a mechanical fuel pump, Berkeleys used an electric fuel pump and a rearward-mounted fuel tank.
With a curb weight of between 700-800 pounds, the Enfield produced enough power to give Berkeley drivers a fun time behind the wheel. Unfortunately, the good times didn't last, as the company had quit making the cars by 1961. Only 4,200 were built, and just 1,000 made it to the U.S. Pfeifer's car is a B95 model, and only 12 of its kind were sent here.
This article originally appeared in the June, 2008 issue of Hemmings Motor News.
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