Lotus Type 50 - Elan +2
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Engine, The Lotus Twin cam

The Lotus Twin cam is one of the great engines, yet comes from humble origins, having a block originally found in the Ford Anglia 105E.

General description

The engine is a four cylinder, four stroke, twin overhead camshaft unit, with a cast aluminium cylinder head. The head is machined to have hemispherical combustion chambers and a separate port for each of the valves. The camshaft is driven by a chain at the front of the engine and runs at half engine speed.


The engine was produced in various configurations, increasing in power and with variations to conform with Federal regulations. Many current cars do not carry there original engines, having received replacements from other sources, or having been modified to more powerful specification. The main types found in the +2 were as follows:

  Carburetors Output Suffix /
Cam Cover colour
Fitted in
Special Equipment Twin Webers 118 bhp F / red +2 and +2S
American Federal Twin Strombergs 108 bhp M / red +2 and +2S Federal
Big Valve Twin Webers 126 bhp P / black +2 S130
Federal Big Valve Twin Strombergs 113 bhp U / red +2 S130 Federal
Big Valve Twin Dellorto 126 bhp EN / red +2 S130

The different versions

Special Equipment Webers American Federal Strombergs

Big Valve Webers

Federal Big Valve Strombergs

Big Valve Dellorto

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