Info for a Dennis Required

I am writing to you from Johannesburg and would like to know whether anyone can identify the year of manufacture of the bus in the attached photo please.
Our family hails from Walsall and my dear old Dad, Sidney Lockley, pictured in the photo, used to drive buses for Walsall Transport prior to WWII and after the war too, before he emigrated to Rhodesia in 1947.
I see from the photo that the bus may be a Dennis and it looks as though it may have been used on the Hednesford route, if I rightly interpret the signage on the bonnet. The white wall tyres are unusual.
Please would you be so kind as to let me have any info on the bus, particularly on the year of manufacture and the model? To see a photo of the full size bus would be wonderful too.

Sue Heyl

07/11/15 - 16:34

Thanks, Sue, for the photo of your Dad proudly showing off the Gardner 4L2 oil engine that had replaced the original petrol engine of Walsall no. 49 (DH 5500), a 1926 Dennis E-type with Vickers B31R body. The new Gardner engine must have halved the fuel consumption but it will also have given rise to a good deal of vibration and---I guess---very heavy steering.
A search took me to the National Archives website, where this bus is said to have been fitted with a Gardner 4LK, but that can't be right, as the 4LK is a very much smaller engine and wasn't even yet in production at the time of this photo. Incidentally, the Dennis Society website has a fine article by Jack Haddock on the trials of starting, driving and maintaining Dennis E-types so never let anyone dare suggest that your Dad had an easy life!

Ian Thompson

07/11/15 - 16:35

I'd say that it was a Dennis E, or one of its derivatives, the ES orEV, the first of which was produced in 1925 and would have had pneumatic tyres from the outset and, a first, brakes on all four wheels instead of only the rear ones! The chassis could accommodate a thirty-seat body, 25 feet long and 7ft 1in wide. They started with a four-cylinder petrol engine, but the EV had a 70hp six-cylinder one. In those days, the life of such a bus was unlikely to be more than ten years, possibly less. Walsall, however, had to keep them going throughout most of the war
The word Dennis on the front makes me wonder if the bus is a demonstrator, for bus companies to try out.
There is a really interesting history of these buses at the following link, including a photo of a Dennis E with destination board on radiator SEE; www.dennissociety.org.uk/nl/walsall.html
Incidentally, Hednesford is pronounced Hensfud!

Chris Hebbron

07/11/15 - 16:35

The bus is Walsall Corporation fleet number 49, registered DH 5500. It was a Dennis E-type fitted with single deck 31-seater rear entrance bodywork built by Vickers, and new in 1926. Originally petrol-engined (as were all buses of the period) it was experimentally fitted with an early Gardner oil (diesel) engine in 1930. It was taken out of service around 1944, and was scrapped in the Cannock area in 1946. (This is according to an old PSV Circle fleet history of Walsall Corporation dating from 1965).

John Stringer

08/11/15 - 09:47

The answer to the specific question about date and model etc : 5500 looks to be in the same condition as DH 4905 (the second photograph in the linked article) - i.e. Dennis E from about 1926 with the original Vickers body. The third photograph in the article shows DH 5505 - presumably from the same batch - as rebodied in 1935 by W D Smith. Assuming 5500 was rebodied about the same time, this may help to date the photograph?

Stephen Ford

11/11/15 - 07:15

I thought I should just add a little about the engine it was the same swept volume as the later 4LW but the L2 range were designed for marine use and launched in 1928.
It just happened that one of the first customers was Tom Barton, the Chilwell based bus operator and by 1929 he had fitted a 4L2 into a Lancia chassis he'd modified to forward control.
Although it displaced 5,580cc like the later 4LW it was much slower revving so peak power was in the region of 5Obhp at 1200 rpm rather than 75 at 1750 for the automotive version. The latter was launched in 1931 and the Guy Arab was the first PSV designed to fit it.

Stephen Allcroft

11/11/15 - 07:17

Some additional comments to those above. The L2 range of Gardner engines was designed primarily for marine applications, and the prototype, tested in June 1929, was a 4L2 with Gardner engine number 28203. This was then exhibited in August 1929 at the Engineering and Marine Exhibition at Olympia where it received just three new orders, two for marine use and one from the forward looking T. H. Barton of Beeston, Nottinghamshire. Barton's engine, number 28423, was completed before the two marine units (28421 & 2) and this became the very first production L2 engine. Thus, the first application of this remarkable power plant was not in a marine vessel but in a bus, a single deck Lancia which bore publicity announcing it to be "Barton's British Crude oil Bus". Barton always refused to use the term "Diesel", a view in which he was certainly correct - Halifax born Ackroyd Stuart has a much stronger claim to be the pioneer in the practical development of the compression ignition principle. The marine setting for the 5.6 litre 4L2 was 38 bhp at 1,000 rpm, but for automotive use this was raised to 50 bhp at 1,300 rpm. The Gardner powered Barton Lancia yielded twice the mpg of the petrol engine it replaced, and after running for 50,000 miles it was sent back to Gardner for examination. No problems whatsoever were discovered, and the unit was then sold on in February 1931 to be fitted into a lorry. It is generally believed that the Barton Lancia was the first direct injection oil engined passenger vehicle to run in the world. The Barton initiative was quickly followed by many others, one of which was the Walsall experiment detailed above by other contributors. The Walsall Dennis E, DH 5500, had its chassis extended by approximately 2ft at the front end to accommodate the extra length of the Gardner 4L2, and was shown at the Municipal Transport conference in 1930. Reputedly it averaged 18 mpg in service. Presumably it was not normally started by hand, though Gardner engines did have decompression levers that (theoretically) provided for hand cranking. The following year, 1931, saw the debut of the new automotive LW range, and DH 5500 had its L2 replaced by a 4LW. As Ian T points out, the smaller 4LK of 3.8 litres did not appear on the scene until 1935, and its installation in the Dennis E would have proved truly inadequate (ask anyone who has driven a Bristol SC4LK). The 4LW was removed in 1932 and sent back to Gardner, probably as part of a proving test agreement, and DH 5500 reverted to petrol propulsion. Whether or not it retained its front chassis extension is unrecorded.
The references to the Dennis E type in Jack Haddock's fascinating memoir on the Dennis Society website have to be put in context. These recollections recount the circumstances of acute wartime shortages and the necessity for often ingenious improvisation. In its day the E type was highly regarded, but the mid 1920s embraced rapid automotive engineering development, and, by 1941, all the bus designs of 1926, the year in which the E type appeared, were well obsolete. The E was the Guildford company's very first bespoke design for the passenger market. The earlier 4 ton double decker and 2½ ton saloon beloved of the London 'Pirates' were both built on modified lorry chassis. Despite having its cab alongside the engine, the E was effectively a semi forward control design with a dropped chassis frame. At that time, its main competitors in the single deck market were the ADC 411//3/5 (surprisingly, still straight frame designs from the maker that pioneered the NS), the Bristol B, the Tilling-Stevens B10, and, of course, the excellent Leyland PLSC Lion. The Dennis had a White and Poppe engine of 6.42 litres rated at 70 bhp, and was equipped with pneumatic tyres and four wheel brakes as standard. In 1928 the original version was updated and tidied up a bit cosmetically as the ES type, but in that same year the EV type appeared with full forward control and a more modern radiator shell, though the ES continued to be available. The "Dennis" badge on the front of the driver's dash panel in the picture of the Walsall DH 5500 was a standard fitment on the E type, though many operators replaced it with their own logos. However, 1927 witnessed the bus industry's "Dreadnought" event. The emergence of the Leyland Titan and Tiger rendered almost everything else obsolescent overnight. By 1929 Rackham had gone to AEC where the Regent and Regal moved things on rather further. It took Dennis and most of the other manufacturers some time to catch up, though Leyland and AEC continued to rule the roost for years.

Roger Cox

15/11/15 - 10:49

Thx, indeed, Roger, for another of your thorough and thoroughly interesting posts, this time on the background to early oil engines in road vehicles, particularly Gardner's. It's amazing that an engine primarily designed for marine use worked so well in road vehicles, too, where the operating environment was so different; steady revs for long periods versus continually changing revs and demands. The fact they were able to up the bhp and revs successfully and maintain reliability was quite an achievement. The story of White and Poppe is something that I recall long ago when reading about German Zeppelins being fitted with their carburettors! They were a very innovative automotive company from the earliest days, a main supplier of engines to Dennis Bros, who eventually took over the firm. Here is a synopsis of the two individuals and the firm: https://union.ic.ac.uk/rcc/rcsmotor/archive/white-and-poppe/

Chris Hebbron

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