It powered Triumph's Le Mans team entries in 1959, 1960, and 1961, and was considered for use in a production road car.
[2] The engine's two prominent front-facing domical camshaft end covers earned it the popular nickname "Sabrina", after contemporary British actress Norma Ann Sykes.
The project, called Zoom, resulted in a full-width body, with tall doors having wind-down windows, and headlamps moved to the tops of the front wings.
By 1959 two Zoom prototypes were complete; one convertible and one coupé with a removable roof panel, both powered by 20X engines detuned to around 120 hp (89 kW).
[8][9][10] By the middle of 1960, Triumph had prototypes for two potential TR replacements — Zest and Zoom — with a combined program cost of £676,000.
Having seen Zoom, some at Triumph wanted it to become the next TR, but the cost to produce the 20X engine in volume killed the project.
The crankshaft is carried in five main bearings, two more than are in the Standard wet liner inline-four engine used in production TRs.
The camshaft drive comes off the nose of the crankshaft via primary and secondary duplex chains with Renold hydraulic tensioners.
[16][17] The Jopp/Stoop TR3S was called in to have its blades removed, then ran as high as seventh place overall before being forced to retire due to an oil pump failure with just over an hour remaining in the race.
[18] Post-race, with clearances restored but prior to a full rebuild, the engines still produced around 120 hp (89 kW).
[5][13] A new body designed by Michelotti was fitted over a custom multi-tubular steel chassis fabricated by Italian engineer and Alfa Romeo tuner Virgilio Conrero.