The Lotus Mark IV is a Roadster from Lotus, built from 1952, at the height of the post-war boom. Under the bonnet: Ford side valve 1172cc. Colin Chapman drew it.
The story
Lotus Mark IV was a trials car by Colin Chapman built on an Austin 7 chassis. Chapman's success at building trials cars brought another previous customer, Mike Lawson, to order a second trials car in 1952 to replace his Lotus Mark II, in which he won the Wrotham Cup. Once again Chapman chose an Austin Seven as the starting point, reinforcing the frame and installing a four-cylinder 1,172 cc (71.5 cu in), Ford, sidevalve engine. Chapman used all the tricks he had learned in his previous cars, constructing a lightweight aluminium body with a rounded nosecone.
He fitted a 3-speed transmission taken from a Ford 8 and the divided front axle as on his previous cars. Lawson won his class in the first attempt in this car, following up with others, solidifying Chapman's reputation as a designer and engineer. The success of this car, and other requests for more cars, led Chapman and Michael Allen to establish Lotus Engineering in a disused stable in Hornsey. Ford Sidevalve Motor Configuration: S4 SV Displacement: 1172 cc Bore/Stroke: 63.5mm x 92.456mm (2.5x3.64")
What is underneath
Power comes from Ford side valve 1172cc. These are manufacturer figures carried by Wikipedia and Wikidata, not road-test measurements.
Its place in the line
Its family tree is legible: it took over from the Lotus Mark III; its successor was the Lotus Mark V. Its contemporaries in the catalogue — the Cadillac Eldorado, the Toyota Land Cruiser, the Chevrolet Corvette — show what else the money bought that year. Nearby in the Lotus catalogue sit the Lotus 100T and the Lotus 101.
What it costs now
MotorJury scores cars on the United States complaint and recall record, and the Lotus Mark IV has none: too old, too rare, or never sold there. Its value today is a collector's question, decided by provenance and condition rather than by a class average.