Fred, if it is history you are after - you didn't say - I can tell you that Frederick Barnes set up an engineering business at Hamilton in 1915. Main business was motor car repairs. Some time between then and 1919, he produced the Model D engine. It had mechanical inlet and atmospheric exhaust valves. See TOMM 127.
In partnership with Douglas Fraser and Edward Shaw, he patented the Model F, 3.5hp engine in Dec 1919. This was the side valve engine we see at rallies today.
There were also 1.5hp, 8hp twin and 14hp 4 cylinder. Ford T parts were used in the 3.5 and 8hp engines at least.
By Feb 1923 the firm was in liquidation, and everything up for sale.
Eric