JS Motorsport’s final assembly shop

Lotus Twin Cam

The Lotus Twin Cam is a 1558 cc engine developed for the 1962 Lotus Elan and also used in a variety of other vehicles up until mid 1970s. John Smirthwaite and his team at JS Motorsport have decades of experience in rebuilding and providing race support for championship-winning Lotus Twin Cam engines. Having earned an unparalleled reputation for excellence and attention to detail, the team is pleased to offer its expertise to customers across the country and also offers wide range of high spec components for Lotus-Ford Twin Cam engines.

Technical Detail of the Lotus Twin Cam engine

The 1558 cc Lotus Twin Cam engine has internal dimensions as follows:

3.250 inches (82.55 mm) bore
2.900 inches (72.746 mm) stroke
The 116E block was used in 5 basic versions
The Mark 1 - from 1962 to 1967
The -6015 block with round main bearing caps and 4 bolt crankshaft
The Mark 2 - from 1967-1975
The 3020-6015 block with round main bearing caps and 6 bolt crankshaft
The 681F-6015 block with round main bearing caps and 6 bolt crankshaft
The 681F-6015 block with square main bearing caps and 6 bolt crankshaft
The 701M-6015 block with square main bearing caps and 6 bolt crankshaft

The cylinder head has hemispherical combustion chambers similar to that first used by Peugeot on their 1912 Grand Prix car and subsequently refined by Jaguar in their XK engine of the 1950s.

Valve sizes used are 1.530" diameter inlet and 1.325" diameter exhaust on all engines except the "big valve" Lotus Elan Sprint and Europa models which have an inlet valve measuring 1.565" diameter.

Power output of the Lotus Twin Cam engine

The power output for roadgoing versions of the Lotus Twin Cam engine are as follows (official figures as claimed by Lotus):

100 bhp (75 kW; 101 PS) Elan 1500
105 bhp (78 kW; 106 PS) Elan 1600, S2, S3
105 bhp (78 kW; 106 PS) Elan S4
115 bhp (86 kW; 117 PS) Elan S2 S/E, S3 S/E, S4 S/E
118 bhp (88 kW; 120 PS) Late Elan S3 S/E
126 bhp (94 kW; 128 PS) Elan Sprint

Contact us today

For more information on any assistance required with your Lotus Twin Cam engine, please call John Smirthwaite at JS Motorsport on 01827 830096.