Vintage Thing No.4.1 - The supercharged two stroke Trojan engine

A chap called David Pickard has sent me a link to the Trojan Trust website where there is a reproduction of an article published in the October 1946 issue of the Commercial Vehicle User's Journal. What wonderful names we used to have for our magazines!

And the engine featured in this article appears to be the same supercharged engine that I found in an old copy of The Motor Vehicle by Newton and Steeds.

This engine powered the 15cwt & 25cwt Trojan vans after World War II and in general terms the Commercial Vehicle User's Journal matches the technical description provided by Newton and Steeds - to wit 24bhp and 1186cc (65.5mm x 88mm). Although it is a four cylinder engine, it has six cylinders - four of them paired in two split cylinders that share a common combustion chamber.

But the most interesting feature of the design is an inlet rotor in the head of the charging cylinders. This is driven from the crankshaft by bevel gears and a shaft that also doubles as the drive for the contact breakers. This rotor ensures a fresh charge of fuel is drawn into the pumping cylinder on the down stroke and then into the transfer ports on the up stroke.

Despite it's prosaic calling in life, I can't help wondering whether the performance potential was ever explored. I feel that there must have been some. In the usual state of affairs these engines drove through a three speed box to a conventional live axle (i.e. not a chain driven one) and lived in a pressed steel chassis on to which was mounted a fibre board body. Brakes were hydraulic.

A 2.3 litre (3.5" bore by 5" stroke) Perkins P3 diesel option came along in 1953 accompanied by a 1.29 litre variant of the blown four. There was also a version of the Trojan van with an electric motor. The accent was always on economy rather than high performance but you could argue that the Trojan two stroke was actually a 2.3 litre six - although I think including the supercharging cylinders is cheating. Production ended in 1959 when Trojan were gearing up for taking on bubble car production but these little vans were immortalised by Dinky Toys. And I had one of these models when I was a mixed infant at Goonhavern County Primary School! If only I'd known it was a supercharged - I might still have it today instead of later setting fire to it along with all my other model cars.

Gentle reader, fear not - I now weld regularly and this has kept such behaviour at bay.

This picture is a press release photo supplied by the Trojan Museum Trust and illustrates among other products the van on the right and the minibus variant on the left. I find myself liking the body styling of these two post war vehicles. They are simple but quite distinctive.

When it came to going to racing the Trojan company had links with Elva and even entered Formula 1 with a Cosworth DFV V8. This sounds like an easy alternative to wringing more power out of their two-stroke van engine but "woarr though eh?" Somebody must have had a go at seeing "what'll she do mister?" even if it was out of sheer curiosity.