Historic Truck Brands
Sentinel
UK manufacturer, Sentinel Waggon Works Ltd was a British company based in Shrewsbury, Shropshire that made steam-powered lorries, railway locomotives and after World War II, diesel-engined lorries, buses and locomotives. The company ceased operating in 1956.
Sentinel remained stubbornly attached to steam propulsion, selling its last export steam trucks into a mine in Argentina, as late as 1950, but volume production of steam vehicles ended with the advent of WWII.
By the late 1930s it was obvious even to Sentinel management that the future propulsion for trucks would be petrol and diesel – not steam. The company wanted a style of engine that would suit installation in buses as well as in trucks.
The obvious choice was a horizontal layout, as already adopted before the War by Bussing and the first post-War Sentinel trucks were petrol fuelled, four-cylinder models.
A couple of prototype 6/7 ton payload lorries were tested by the trade press in late 1945 and the reports pointed out that most of the other truck manufacturers in the UK were building trucks with diesel engines.
It seems that’s when engineering consulting firm, Ricardo, was called in to help. Ricardo redeveloped the engine for diesel combustion, using an indirect injection design. The 90bhp, four-cylinder engine proved to be very quiet and powerful.
Sentinel produced its own chassis, cab and engine, but bought in components, as did some other UK truck makers. Sentinel used a Coventry Radiator cooling system; David Brown five-speed, constant-mesh gearbox; Kirkstall Forge axles; Girling and Lockheed brakes; and CAV and Simms electrics.
The truck cab design was interesting in its use of sliding doors that allowed entry and exit in narrow laneways.
The pre-chamber diesel engines had glow plugs, but proved tricky to start in cold weather, suffered from overheating and were thirsty. The underfloor mounting system was fragile and some vehicles actually had engines sag or drop out!
These early engine issues halted Sentinel’s post-War momentum in the underfloor bus business.
Commercial Motor magazine tested an early Sentinel 90bhp truck and reported favourably on it. Despite its underfloor location the Magazine said that maintenance access was very good.
A full-width seat was provided and although the fan tunnel bulged up in the centre of the floor boards, the cab was spacious, with excellent visibility.
Commercial Motor had no overheating issues, but did point out that the mercury was sitting at 35 degrees F.
Fuel consumption, at a GVM of more than 12 tons, was just under 12mpg.
By 1952, Ricardo had redesigned the engines for direct injection, using its Comet head design and they had better cooling systems. A six-cylinder, 135bhp engine and three-axle trucks were added to the range.
However, the UK gross mass regulations favoured the 8×4 truck configuration over the six wheelers that were popular in Europe, but that configuration wasn’t suitable for Sentinel, because of its post-front-axle engine location: there wasn’t space for the second steer axle.
The 8×4 configuration was dominant at the heavy end of the UK market and Sentinel could get none of that business, so the company was in serious financial difficulty by 1956 and was forced to sell out. Rolls Royce bought the factory and began building its own range of diesel engines. That didn’t have a happy ending either!
It seems that around 1200 Sentinel diesel trucks were made between 1947 and 1956, but there are very few survivors – many of which were re-powered by Gardner, with a horizontal version of the 5LW five cylinder, 100bhp engine.
Some trucks were converted to vertical engine location and others were produced by TVW, with vertical engines, after 1956, until the early 1960s.
Sentinel trucks Down Under
Sentinel trucks were advertised in the November 1951 edition of Truck & Bus Transportation Magazine – the Australian industry ‘bible’ in the 20th century. The dealers were Sidney Palmer Ltd, Stanmore, NSW; Austin Distributors, South Melbourne, Vic; BEA Distributors, Adelaide, SA and Wigmores, Perth, WA.
In the June 1953 edition of T&BT there was a Sentinel article about Clintons Nattai Colliery, of Camden, NSW, who had five Sentinel trucks in its fleet.
Like most Pommy, Euro and Yank trucks with five-speed main boxes, the Australian-market 4×2 Sentinels were fitted with two-speed drive axles. We’re not sure what the transmission arrangement was with the six-wheelers.
There are reports of at least one surviving Sentinel in Australia and we’d love some information on it.
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