In order to provide the truck and bus industry with a lightweight diesel engine that provided low weight to power ratio a new Gardner engine was designed. The first LK prototype engines were made In early
1934. The first was a six cylinder engine with the serial number 31891, two six cylinder LK engines were built and subsequently fitted in Gardner owned motorcars. The six cylinder LK engine never went into production and the two six cylinder units that were built are in the hands of Mr Paul Gardner of the Gardner family.It was decided not to build a six cylinder LK engine but to build a four cylinder version named the 4LK. The first 4LK engine serial number
34405 was built and tested on 10th of October 1935, most were fitted into Foden and ERF trucks although a number of private car owners fitted this light and economical engine in their cars.The cylinder heads, cylinder blocks were cast in Iron the crankcase and base chamber being in magnesium alloy. The engine had a bore of
3.75 inches and a stroke of 5.25 inches resulting in a swept volume of 3.8 litres. The 4LK produced 52 bhp at 2000 rpm later increased to 57 bhp at 2100 rpm. Typical fuel consumption in a 3 ton truck was in the range of 25 mpg, considerably more was achieved by engines fitted into motorcars.Due to the success of these engines and their outstanding fuel economy people started fitting these engines in luxury cars, and due to this demand Gardners' designed a special edition 4LK engine. This engine featured aluminium alloy cylinder heads and cylinder blocks fitted to the standard magnesium alloy crankcase. Only about forty of these special edition engines were produced with a maximum power of 85 bhp at a very high speed of 3000 rpm in the 1930's.
The 4LK was fitted into a number of motorcars from Lagonda's to Wolseley and Jaguars, a Jaguar XK150 fitted with a Gardner 4LK in the
1950's achieved an amazing 90 mpg when competing in a Mobil economy run in Cheshire. Capacity Automotive