I like it! Running up your engine in the back of a Sankey trailer is an 'interesting' way to get first-smoke.
On a much-more-micro scale I once conspired with the owner of a Heinkel bubble-car to replace the seized single-cylinder sub-200cc engine with a 3-cylinder Klockner-Humbolt-Deutz marine Diesel engine of about 1.5 Litres, and a centrifugal clutch. The usable rev-ranges of the two engines didn't coincide too well so some obscure shaft was turned-round in the gearbox. The KHD had so much torque a gearbox was unnecessary except for starting on the steepest of (Dutch) hills. 0-135KM/h in 2nd gear was fun. Eventually it caught fire catastrophically while stuck in a traffic-jam somewhere between Breda and Doordrecht.