The Keil K6 was a short-lived spark ignition engine which was introduced to the British market shortly after World War II by KeilKraft Ltd. under the leadership of Eddie Keil. There has long been an anecdotal tradition that the engine was designed for KeilKraft by Harold Kemp, who is known to have been a business associate of Eddie Keil. However, this suggestion is completely unsubstantiated - indeed, the engine displays little evidence of Kemp's subsequent design and manufacturing styles. The true identity of the engine's designer/manufacturer has never been established.
The first advertisement for the K6 appeared in the March 1946 issue of "Aeromodeller" magazine. The engine was subsequently advertised on a rather intermittent basis, the final advertisement appearing in the November 1947 issue of "Aeromodeller". Mention was made of 3.8 cc and 10 cc companion models, but these never appear to have materialized.
Although always cited as a 6 cc unit, the K6 featured bore and stroke dimensions of 19.84 mm and 20.64 mm respectively for an actual displacement of 6.38 cc. It weighed in at 214 gm (7.55 ounces).
The engine appears to have been produced in relatively small numbers. It is rather fragile (check out those mounting lugs!) - good examples are quite rare today. My own illustrated example, engine no. 214, has an interesting history! It was originally owned by Eddie Keil himself but was presented by Eddie as a gift to his friend Fred Johnson at a meeting at Fairlop in 1946. Fred had kept it ever since. I acquired it from Fred in 2011, shortly before his death, along with its story. I am thus only the 72 year old engine's third owner!
A brief article about the Keil K6 may still be accessed on Ron Chernich's "Model Engine News" (MEN) website.