The Monarch 600 was Canada's one and only all-out racing engine. This 9.90 cc (0.604 cuin.) twin ball-race disc rear rotary valve spark ignition unit was produced to high standards in very small numbers in Toronto, Ontario by a manufacturer called Monarch Motors at a cited address of 169 Audrey Avenue, Toronto 13. The engine displayed a number of highly original design features.

The date of this engine's manufacture has previously been cited as 1940/41 on a purely anecdotal basis, but several pieces of hard evidence suggest that the period 1946/47 is far more likely to reflect the true dating. Whenever it was produced, the number manufactured was extremely small, likely coming nowhere near reaching three figures. The engine was most likely manufactured by an artisan constructor working in a home machine shop and serving the local Toronto-area market on a custom order basis. Only three surviving examples are presently reported, although there are almost certainly a few more out there.

A full report on the Monarch 600 may be found elsewhere on this website, togther with an overview of model engine manufacturing in Canada.