A 997cc Cortina-based engine with an overhead cam alloy head that revs to 11,000 rpm? Scream if you want to go faster with the Cosworth SCA.
With a new 1-litre F2 category due in 1964, Ford commissioned an engine from Cosworth. Basing this on the existing five-main-bearing Cortina 116E cylinder block, Keith Duckworth designed his first-ever aluminium cylinder head, complete with single overhead camshaft and two vertical valves per cylinder. Drive to the cam was by a train of gears, and the combustion chambers were formed in the piston crowns. As with all future Cosworth race car engines, it was miraculously compact.
Up until this point, Cosworth had concentrated on modifying the Ford Anglia/Classic/Cortina engines (the most famous, MAE, being the Modified Anglia Engine), so new engineering for the SCA was a real shot-in-the dark. Duckworth had to play safe, by improving on what other engineers had already done but soon started to develop novel, and forward-thinking, ideas of his own.
This engine was always purpose-built for F2, which explains combining the five-bearing Cortina bottom end with the bore/stroke dimensions of the original 997cc Anglia. The final engines peaked at more than 11,000 rpm, when they reached their breathing limits. Driveability was always a problem — but there was never a need for them to be used at low-speed or in heavy traffic.
To fit the tiny single-seater race cars from Lotus and Cooper, the SCA engine was designed to be canted over at an angle in the chassis, so the steeply angled inlet ports ended up vertical, the carburettors being immediately behind the driver’s head. In later years Duckworth was ashamed of this: “The SCA was the first cylinder head that I ever designed, and now I think there was a lot wrong with it. We had all sorts of trouble with the combustion — we couldn’t make it burn — but it was still good enough to win a lot of F2 races…”
Having started life with an impressive 115 bhp, the SCA was eventually persuaded to produce up to 143 bhp (from just 997cc, though with an early type of Lucas fuel injection), but by 1966 it had been matched by a new and complex F2 engine from Honda. Cosworth had, however, also learned enough about four valves per cylinder to banish two-valve heads for ever.
Cosworth SCA: the spec
Used in: 1-litre F2 and other race-car series
Layout: four-cylinder, single overhead cam head, two valves per cylinder
Capacity: 997cc (later 1098cc and 1498cc)
Block/head material: Cast-iron/cast aluminium
Power: 115 bhp from 997cc, rising to 140 bhp by 1966, 175 bhp from 1498cc
Words Graham Robson
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