Commer TS3

The petrol version used a development of the Humber Super Snipe engine, lying at a 66 degree angle, and the opposed piston design of the TS3 was used so that it would fit in the same space.

It is often thought that "TS" in the engine's name derives from its Tilling-Stevens origins, a company acquired by Rootes in 1950 but this is incorrect.

Development of the engine started at the Humber plant at Stoke Aldermoor some four years before Rootes had acquired Tilling-Stevens.

In general the engines gained a reputation for good performance, but this quill shaft was somewhat prone to breaking if over-worked.

The later United Kingdom 3D215 and 3DD215 TS3 motors had the Clayton - Dewandre SC-6 compressor fitted with a harmonic damper which removed any timing gear clatter.

Initially these were a sales success, as they were more reliable and economical than the then-current diesel-engined variant of the Bedford SB, however the noise produced by the TS3 was not acceptable to tours operators and the higher body mounting compared with the SB required extra work for coachbuilders and made the Avenger more expensive than the Bedford.

The last straw was in 1957 when Ford announced a PSV version of its Thames Trader, which could take an identical body to the SB and had a conventional six-cylinder diesel engine (which turned out to be quieter than either the TS3 or the Perkins R6 fitted to the SBO).

It's notable that Thomas Harrington Ltd never tooled updated versions of its Crusader body for the Avenger, although that is also perhaps due to the conservatism of the combination's sole customer Southdown Motor Services.

Opposed-piston diesel engines are rare enough at this size, the rocker lever arrangement was almost unheard of.