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LMC Era Component Cross-Use
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Author:  9711T [ Sat Apr 05, 2014 1:51 am ]
Post subject:  LMC Era Component Cross-Use

An interesting facet of the LMC era was the cross-use of major components. That happened in a fairly major way after Leyland acquired Albion, and to some extent after the ACV acquisition as well.

The first example following the ACV acquisition appears to have been the use by Leyland of the AEC D197 gearbox in the Low-Weight Badger tractive unit, announced 1963 June.

This was the first extension of Leyland’s “Low-Weight” range, which had been started with the Low-Weight Octopus, announced 1962 October just ahead of the ACV merger announcement. After the Badger came the Low-Weight Retriever, announced 1963 August.

The Low-Weight Octopus had been fitted with the standard version of the Power-Plus O.600 engine, with its customary 140 hp at 1700 rev/min setting. It had an alloy-cased version of the “new” (1960) heavy-duty gearbox, with the overdrive option but as far as I know without the crawler option. It used the non-reactive four-spring rear suspension that had been introduced with the reworked 1960 heavy-duty range, but with the “small” three-planet hub reduction axles, similar to those used on the Albion Reiver. Whereas the Reiver tandem drive was of the pillow-block type, that on the Low Weight Octopus was of the through-drive type, as was that on the LAD-cabbed Hippo and Octopus heavy-duty models announced 1960 September. The forward axle on the Low-Weight Octopus looked somewhat like an Albion Reiver forward axle with the interaxle differential and transfer gears case bolted on to its front.

It is reasonable to assume that Leyland had planned a full Low-Weight range from the start, and one wonders what were its ideas for the four- and six-wheeled counterparts to the Low-Weight Octopus before the ACV merger was consummated. Was it perhaps pondering how to reduce weight even more than would be obtained by making these homologues of the Low Weight Octopus? And did the acquisition of ACV provide it with a previously unforeseen opportunity to do this through the use of a lighter gearbox? The time gap between the release of the Low-Weight Octopus and the introduction of the Badger at least suggests that Leyland took time to rethink the project.

The Badger was fitted with a derated version of the O.600 engine, whose curves were apparently designed to fit within the envelope allowed by the AEC D197 gearbox. So one may assume that the latter was pivotal; its perhaps sudden availability as a result of the merger provided a not-to-be-missed opportunity to reduce weight by using a gearbox that was intermediate in capacity and weight between Leyland’s GB241 (not big enough for the job) and its heavy-duty model (oversized for the job).

The version of the O.600 used in the Badger was set to 140 hp at 2200 rev/min. That was actually a derating in mean effective pressure terms, even though the power output was the same as standard. The 2200 rev/min rated speed was neither new for the Power-Plus O.600 nor for Leyland’s “big” engine. The Leopard bus chassis, which had originated in pre-Power-Plus days, had been switched over to the Power-Plus version by 1961 May. With that change, two settings were available, “bus” with 125 hp at 1700 rev/min and “coach”, with 130 hp at 2200 rev/min. With the earlier O.600, there had been one standard setting, namely 125 hp at 1800 rev/min. And the Power-Plus version of the O.680 had started life with a standard setting of 200 hp at 2200 rev/min, although I have heard anecdotally that early versions were not too happy at this rotational speed. If so, that might have been the result of Leyland’s rather hasty and allegedly underfunded effort to catch up with what was happening in the worldwide marketplace. By then it was probably evident that to meet future power and power-to-weight ratio requirements whilst retaining sane envelope sizes, automotive diesel engines would need to be pressed much closer to their mechanical limits. That meant mean piston speeds of around 10 m/s, with commensurate rotational speeds. Improving direct injection combustion technology had allowed a steady increase in maximum rotational speeds, from around 2200 rev/min in the late 1940s, to 2800 rev/min by the late 1950s, and even higher than that by the mid-1960s. For the larger engines, piston speed not rotational speed was anyway the limiting factor. Cummins was an early mover, with its HF6 engine (“FH” for “fast” H) in the mid-1950s, this pointing the way to its very successful NH, (“new” H), NT and N series engines, which pretty much defined the “big in-line 6” in some markets for quite a few years.

Of course, Leyland had to be somewhat Janusian, and provide somewhat different offerings for the domestic market, particularly in respect of the preference for more moderately powered vehicles. Hence the Power-Plus O.600 in standard form, which with its 1700 rev/min rated speed was fairly clearly intended to go up against the “legendary” Gardner engines. Actually, the legend became a bit tarnished when Gardner eventually had to up-speed and turbocharge its engines to align with modern practice.

Anyway, to return to the Badger, whilst derating the O.600 and running it at 2200 rev/min might have been a forced choice in order to match it to the D197 gearbox, it could also have been a positive in and of itself for this class of vehicle. The Badger to some extent would have been competing in the AEC Monarch/Mercury class, and here medium-sized engines with rated speed around 2200 rev/min would have been the norm. One may wonder whether or not Leyland considered using the AEC AV470 engine in the Badger, but even if suggested, one hopes it was dismissed fairly quickly. For whatever part of the market Leyland hoped to obtain, it seems likely that a derated O.600, notwithstanding its weight penalty, would have more appeal as being a differentiated offering than another AV470-engined chassis. Of course, this highlighted the lack of a mid-sized block in the Leyland engine range, but evidently the potential market was not big enough to justify the development work required in the early 1960s, and once the fixed-head 500 was in view, any conventional solution may have been outruled. Development of a six-cylinder version of the Albion EN335 “four” comes to mind as being one way in which it could have been done. But Albion’s reputation with engines was a bit patchy; the EN218 family and EN900/O.900 were evidently somewhat troublesome.

The rear axle choice might have been a problem. The “big” hub reduction axle, as used on the Beaver, would have been too heavy, whereas the “small” version could not handle more than 125 hp. The solution was an Eaton 18800 two-speed driving head, with electric shift, in a Leyland casing. This was in fact a very “Leyland” approach, simply being a heavier duty version of that used on the Comet and Super Comet models.

The AEC D197 gearbox, along with its D203 heavy-duty stable mate, were new at about the time of the ACV acquisition, and both were described in AEC Gazette, 1962 September-October. In some ways the D197, with its straight-toothed gears and sliding mesh first, was a back-step for Leyland. By then its current gearboxes used helical-toothed gears for 3rd gear an upwards, and had constant mesh 1st gears. Actually, constant mesh 1st gear was an Albion feature back in the days when Leyland was still using sliding mesh 1st (and sometimes 2nd) gears. But it was adopted by Leyland, firstly for the reworked four-speed bus gearbox, then for the GB241 in 1958 and the new heavy-duty gearbox in 1960. Albion, like AEC, had favoured straight-toothed gears, and it might be noted that its so-configured GB236 five-speed unit remained an option on the Tiger Cub right through to the end of that model’s production run. So the straight-toothed D197 was not quite without a sibling in the Leyland world. Leyland’s D197 experience must have been reasonably satisfactory, as it that model was used as the basis as the gearboxes for the new Lynx and Bison models in the BLMC era. Or maybe, having spent too much of its budget pursuing a silly new engine design, the gearbox had to be done as cheaply as possible by updating and existing design, for which the D197 was “it”.

The Leyland Low-Weight Retriever combined the engine and gearbox of the Badger with the tandem rear axle assembly of the Low-Weight Octopus. All three Low Weight models were carried across into the Ergo cab era with essentially the same configurations. The Ergo cab range also included a new model, the Low-Weight Hippo 6x4 tractive unit, which had the O.680 engine but otherwise had the same running units and rear suspension as the Low-Weight Octopus.

Greater integration came in the 1964 September flurry of new model announcements including the new shared Ergo cab and the fact that the AEC Swift rear-engined bus chassis was basically a Panther/Panther Cub with different running units. The AEC engines were upgraded, although not to full Power-Plus standards. Maybe for a few extra dollars over what was spent anyway, Leyland could have an “O.500”. But presumably by then LMC did not want any crowding of the way to its future big “fail” with its fixed-head 500.

Ergo cab aside, the AEC “T” prefix trucks released around 1964 September initially retained heritage-AEC running units. It would appear that more effort was expended on updating the AEC truck range for the Ergo era than was done for the Leyland truck range, which in most cases was not too much more than a “cab-swap” exercise. It was a case of history repeating itself. In the major rework of the Albion and Leyland lighter truck range that came with the introduction of the LAD cab, it was the Albion models that received major attention and changes, whereas the Leyland Comet models retained much of what went before.

The first example of Leyland running units in an AEC truck that I have found information for is the export Marshal. A 1966 April brochure shows it as having the Leyland four-spring non-reactive rear suspension, albeit with AEC axles. In contrast, a 1966 August brochure for the domestic market version shows it with the AEC simple balance-beam underslung four-spring suspension. What is unknown is just when the Leyland suspension was first offered on the export Marshal, and why. Then a later, 1968 July brochure for the export Marshal shows it has having two-spring rear suspension, but of a variety where the pivot beam was above the springs, and formed a through-the-chassis cross member. This did not correspond with either the AEC or the Leyland established heavy-duty two-spring suspensions, which had the usual trunnion form. This was in the BLMC era, though, where mixing-and-matching occurred to a greater extent. As noted elsewhere, this iteration of the export Marshal also has the option of the AEC 12-speed splitter gearbox, originally developed for Guy in 1964. One wonders if LMC/AEC had given Guy exclusivity in its use (although quite why it would do that is hard to fathom), but that the inclusion of Guy into BLMC had effectively made it available to the whole group.

Back to the LMC era (just), the application of the 10-speed Pneumocyclic gearbox to the AEC Mandator would I think count as component cross-use. I don’t know whether this variant of the Pneumocyclic was Leyland-built or SCG-built, but I doubt that it was Southall-built, even though AEC had been a licensed producer of SCG designs. As far as I know Leyland had developed and owned the pedestal-type gearshift though (perhaps with some Westinghouse input), so this was definitely a heritage-Leyland item. (The Leyland pedestal shift had also been used by Atkinson, and on paper at least, by Daimler.)

Were there any other examples of Leyland units being used in AEC trucks and buses in the LMC era?


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AEC Marshal Export 196604 p.02,03.jpg
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Author:  Stephen Allcroft [ Thu Apr 10, 2014 3:17 pm ]
Post subject:  Re: LMC Era Component Cross-Use

LMC Hybridisation etc.
The low-weight Octopus was a replacement in the Leyland Motors line-up for the Albion Caledonian 24C. This was announced in 1957 at the Kelvin Hall Show as a home market model and the units were a mix of Octopus engine, clutch and gearbox with Albion HD57 axles in a frame of typically Albion design (channel longitudinals and tubular transverse members) using special steels and light alloys to reduce unladen weight, like the HD57, the first axle was un-braked intially. A down-specced Leyland ‘Mouth Organ’ cab was an option as was the Holmes of Preston ‘Homalloy’ GRP cab, initially there was a 24C/1 haulage model, followed 6 months later by the 24C/3 tipper, which had continuous flitch-plates inside the frame longitudinals; The majority of Caledonians sold were the post-1960 24C/5 fuel tanker variants for Shell Mex and BP Ltd, Alfred Miles Ltd of Gloucester supplied GRP cabs and lightweight tanks, these had a front chassis extention which could fit a long-door LAD cab, although the Miles cab had a shorter door it had a step plate in the front overhang favously the two flat panes of the windscreen on this cab were angled forward.
According to Adams and Milligan the announcement of the low-weight Octopus at Earls Court in 1962 (i.e just after the Leyland-ACV share exchange and prior to the vesting of LMC) spelt the end for both the Caledonian and the Albion overhead-worm axle. Albion actually produced two futher rigid eights, both extensions of the Reiver range, one, the LAD-cabbed CA81 Cameronian, was offered in the UK (1966-9) but mainly sold in Australia, the later Leyland Reiver 8, with the G-Cab and 411 engine was exclusively sold there.
As the Lowlander was being assembled at Scotstoun from 1961 for a prime customer based in Edinburgh [it was perhaps a better use of capacity, also taking into account the growing demand for the mainstream Markland-stlye Albion Cheiftain Clydesdale and Reiver to build the Caledonian’s sucessor at Leyland. One of the Shell-BP units survives in post-showman condition. Readers of regular postings to the forum will notice that 24C is part of contemporary Leyland Motors truck nomenclature so the Caledonian was planned although not produced near Preston.
I feel almost certain that the semi-automatic gearboxes used in Ergomatic-cab AEC haulage models were not only of LMC Rationalised Pneumocyclic design but produced at Leyland. With the success of the Pneumocyclic world-wide at the heart of the Worldmaster, Leyland felt that it was the way forward for trucks too, so they fitted it as standard to the 1964 Freightline Beaver, I would doubt that AEC would have been allowed to produce a parallel haulage-biased semi-automatic transmission under AEC ownership.
The 6U2R and 6MU2R Reliances used the Rationalised Pneumocylcic, presumably built at Leyland, and the same is true for Swifts from at least 3P/3MP onward, and the Sabre VP. The London Country RP/RB 6U2R coaches had a right hand gear control using a Leyland-National style shift unit.
SCG were at the time still building gearboxes for BMMO aka Midland Red to (uniquely hydraulically-actuated) semi-auto designs used in their D9, CM6 and S17-23 PSVs but also were facing rapidly growing demand for the RV68 reversing design for Bristol Commercial Vehicles, first shown at Earls Court 1966 in the Bristol RE; only Luton Corporation and Southdown Motor Services, of open-market customers, ordered RE buses with the Bristol synchromesh gearbox, the last manual RE coaches were completed in 1967/8 with F-suffix plates.
All of the THC customers had the SCG gearbox in their RE buses for 1967, by 1967 some Lodekkas were also using SCG transmission (as had Dennis Lolines from 1962) and a few late MWs on D and E plates may have done so too; some early batches of Bristol LH6L for the Mansfield District/Midland General and Hants & Dorset/Wilts & Dorset operations also used SCG transmission, in all cases with electric shifts. Among the first non-THC customers for the semi-auto RE, in the 33ft RESL form, were Coventry Corporation, whose examples had Eastern Coach Works bodies with a mix of series I and Series II features, after the 1964 Atlantean controversy, Coventry Council’s transport committee must have felt that Coventry-produced gearboxes would be enough to stave off demands to purchase 33ft Roadliners.
Atkinson Lorries (1933) Ltd had a singular relationship with Leyland Motors, which perhaps dated from their predecessors taking over Leyland’s steam Waggon designs; at some point (I surmise before or just after the reconstruction in 1933) Leyland Motors took a stake in Atkinson, it was substantial enough in 1969 to be regarded as a ‘blocking stake’ delaying Seddon’s take over of Atkinson until it received BLMC’s consent to sell its interest, but this it seems was treated in the Spurrier era as an investment and Leyland units of any sort were absent from Atkinson’s lorries and buses from 1933...
…until 1954 and the Atkinson PD746, the only Atkinson double deck bus, two were shown at Earls Court, a chassis PD746S which claimed a five-speed Leyland Pnemuocyclic overdrive gearbox, and the bodied PD746 which had a central-entrance body by Northern Counties Motor and Engineering Ltd for the Stalybridge, Hyde Mossley and Dukinfield Joint Transport Board. As shown it had a David Brown Synchromesh gearbox.
The show chassis was dismantled and the SHMD bus UMA750 was fitted with a Pneumocyclic before it entered service, this (Preserved by the Transport Museum Greater Manchester) as far as I can ascertain is a four-speed unit, with CAV electric control, in advance of contemporary Titans and contemporary with XTC984 the second PDR1 Lowloader, a five-speed overdrive transmission would have fitted in with North Western Road Car Company’s desires [they had commisioned the Alpha] but, it seems, like Guy and Daimler, Atkinson were de-listed by BET as preferred suppliers; the same may also have happened to Dennis, prior to the Loline.
Offering a Gardner 6LW-powered double deck was hardly pioneering. In the 1950-56 period, Bristol (only for the British Transport Comission companies) Daimler, Foden and Guy offered Gardner engines as standard and both AEC and Dennis offered them as optional fitments, I don’t think AEC publicised the option very widely, although Glasgow Rochdale and Aberdeen took numbers of 6LW Regent V, and a 5LW version on narrow track was drawn up, presumably for a Sunderland tender requirement, Norman Morton at the time combining lightwight narrow coachwork, tin-fronts and preselective transmission with 5LW power as his double-deck standard; conversely many more Dennis Lance III were built with Gardner engines than the ostensibly standard Dennis O6 engine. The O6 was initially offered (in the large displacement 8-litre version) for the Loline, but there were no takers and the last Dennins-powered PSV was the final Lancet UF, delivered to Glenton Tours in 1960.
The only Atkinson buses I know of to have been fitted with the classic Leyland Pneumocyclic pedestal-shift were Sunderland Corporation 46-8 (WBR246-8) although 46 was initially supplied with a David Brown manual gearbox and returned to Atkinson for a semi-auto unit prior to Sunderland licensing it. These three, the last Atkinson Alphas built [Type PM646HLW], had an 18ft wheelbase for a 33ft bodied length, a nearside drop-frame to the front entrance and received the first Marshall bodies to the 1963 BET outline for a non-BET customer, to B45D layout, and the first sub 36-foot BET bodies with peaks and double-curvature glazing at both ends. 47 is the only one to have been scrapped. 48 is stored in TWPTE livery pending restoration and 46 is in active preservation, in original livery; it also has a driveable electronic representation in Midtown Madness 2 format. What is even richer and stranger is that these buses have vacuum brakes and air-operated gearboxes, both entry and exit doors work from the 24v electrical system. During 1964 Atkinson advertised the 6HLX engine and a 36ft (18ft 6in wheelbase) option, one presumes air-brakes would have been fitted.
I subscribe to the Daimler Roadliner Yahoo!Group and I’ve not yet to find a Roadliner equipped as new with the Pedestal-shift, but correspondence there from former PMT employees state that air-shifts were refitted to PMT Roadliners to slow gearchanges and mitigate the overspeeding to which the Cummins V6-200 VIM was prone, Roger Davis of Classic Bus fame has said Trent’s RCH-F Fleetlines were also equipped with air-shifts from new for the same reason, although these were Gardner 6LX powered.
Guy built under SCG licence until at least the end of Wulfrunian Production in 1965, but later Arab Vs, notably late China Motor Bus batches, had Daimler-built gearboxes and underslung worm rear axles, as bus components were rationalised under Jaguar ownership, likewise when Jaguar bought Guy the solid-transmission option in the Daimler half-cab changed from a David Brown synchromesh to a Guy constant-mesh unit.
The BLMC Victory J had either SCG or in the case of the Hong Kong double-decks Voith transmission. Daimler production of Gearboxes under SCG licence came to an end in 1974 when Fleetline production was moved from Radford to Leyland, Daimler built the last pre-selector gearbox for Northampton in 1968, quite fittingly as Daimler had patented the combination of this gearbox with the Vulcan-Sinclair fluid-coupling in 1930; when the patent expired in 1946 Guy were the first not previously licenced to offer the preselector and Fluid-Flywheel combination. Leyland did not take up a licence from SCG, after purchasing AEC-built units, for London Transport, Auckland (NZ) and Leeds it instead did a Victor Kiam and bought the company.
Between 1930 and World War Two Crossley (like MG, Riley, ERA and Armstrong-Siddeley cars) had offered the SCG preselector gearbox with a friction coupling, I don’t know about Crossley; or Armstrong–Siddeley, who had the same parent company as SCG; but the smaller cars just used the ‘Wilson box’ without a clutch, Sunderland took pre-select Crossleys to go with COG5 Daimlers; according to David-Kaye’s ‘Buses and Trolleybuses 1919-45’ Guy fitted the Cotal pre-selector in Arab FD48 double-decks for Southampton, this used electro-magnets to engage gear-bands, a French-designed unit, it was used in Delahaye and Bugatti cars, the latter’s petrol-powered railcars and in the Cord 810 series cars in the USA, it was also incorporated in London’s Q188c, the second Double-deck Green Line and the only three-axle double-deck AEC Q, which ended its PSV career in Garelochhead in 1950 after the Foy family took over the H. Brown & Son operation and then it became a pantechnicon in Cheshire until 1953 when (no replacement engine rotating the correct way being available) it was scrapped.
Lord Ashfield of course had used a clause in the Associated-Daimler dissolution agreement to compel Daimler to allow AEC to produce the Preselector unit and the Fluid Flywheel. Referring to the Stewart J Brown book on the Regent V Glasgow (75) and Aberdeen (5) took Gardner 6LW powered examples with pre-war pattern spring–actuated gearboxes and vacuum brakes, Rochdale taking its first 30 of its 40 Gardner-Powered Regent Vs with air-brakes and RT-style air-actuated pre-select gearboxes, I think these (c 1955-9) were AEC’s last build of buses featuring the ‘three-pedal’ epicyclic transmission. Rochdale’s last 10 and the Abredeen examples converted to 6LW from AV470 were Monocontrol.
Seddon, with the RU and the Pennine 7, described the gearboxes fitted as SCG, but I think they were standard rationalised Pneumocyclic units built at Leyland, the same I think is true of the ‘Wilson’ semi-auto optional on Volvo B58s and mainly used by West Yorkshire PTE and Wallace Arnold (the latter choosing it to standardise with a mainly Leopard fleet) and also included in VEB566L the sole UK market B59. The Bristol RE gearbox was built by SCG at least until the end of production in 1980/1, more conventional SCG units going into all VRs and a minority of LHs, the last such being the London Transport BL-class in 1976/7.
During the Leyland Vehicles privatisation process SCG were sold to Cummins, who were quoted as wanting the railway business. Previoulsy most mark 1 and 2 Volvo Ailsa, some Mk 3 Ailsas, Volvo B10M and Citybus, certain Dennis Falcons, all Ward Dalesman GRXI and some MCW Metroliner single deckers had also received ‘SCG’ transmissions.
As to a mid-size Leyland (or Leyland-Albion) engine I doubt severely the idea that anyone in Leyland Motors (pre LMC) felt there was a perceptible gap between the small and the big engines. The Tiger Cub was underpowered, and very short of grunt in coach applications, but that did not stop Southdown (who also used some Beadle-Commer TS3 integral and Commer Avenger TS3 coaches, regardless of the terrain they took their name from) and Ribble Motor Services (to the exclusion of rival models) taking large numbers of Tiger Cub Coaches. Wallace Arnold also took some, despite having contemporary Reliances. Most of the Yorkshire BET coach fleets used the Tiger Cub (the exceptions being Hebble and SUT) and the Northern General Group triple sourced for its coaches, taking Reliance 410s, Tiger Cubs and 6HLW Guy Arab LUFs until the de-listing of Guy by BET, the Reliances and Tiger Cubs working express-routes, the Guys, in two batches, were used for Continental and UK Coach holidays.
Some BET operators, notably Aldershot & District, specified the AH410 on its Reliances as long as the engine was produced, they were among the purchasers of the 4MU Reliance 470 as a coach; a similar preference existed in the Scottish Bus Group; who took most of its Reliances and Monocoaches with the 410 and whose 36ft Y-Type Reliances from 1961-4 were all 4MU versions, including the Eastern Scottish Motorway Coaches...
As the need was felt not to exist then no idea of either devloping the 4-cylinder Albion into a six nor remodelling the 7.1 litre E181 to resemble a modern Leyland unit (perhaps a more likely line of development as the E181 was built until 1952) was felt necessary. Work on a turbocharged 350 had commenced as early as 1952 with Lowloader STF90 and the Titan placed with Edinburgh, but head gasket problems seemed to discourage Leyland from persisting on this: outputs from the larger 375 and 400 in normally-aspirated forms grew to levels near those of the 600, athough turbocharged 400s were offered for the Panther Cub.
When LMC arrived, the medium engine arrived fully-formed, and LMC quickly addressed the weaknesses therein by developing the 470 into the 471 and the 505.
Until 1971 AEC and Leyland/Albion/Scammell had separate home-market sales forces, and this is perhaps why LMC felt it had to offer competitive alternatives by each side of LMC. As I’ve said earlier on this forum the only UK market Albion to have an AEC engine was the AH505-powered Reiver RE126/226 concrete mixer, only produced from 1971.
As for the fixed-head 500, it was originally to be a 700 cubic-inch engine, and examples to that capacity were intensively bench tested, but LMC marketing discerned a requirement for an engine plus transmission of less than 1,000lb weight so the engine was down-sized. It seems I was wrong however in thinking that the 500 series was uprated in response to failures with the V8-800 series as not only is the 500 listed in the BLMC book at 170bhp (seemingly normally-aspirated) but the 520, differing by the turbocharger fitment, is illustrated, rated at 260 bhp, this is before the dropping of the V8 AEC Haulage range and before the launch of the Buffalo and Bison lorries so-fitted at the 1970 Earls Court Show.

Best Wishes

Stephen Allcroft

Author:  mancunian [ Wed Apr 16, 2014 9:34 pm ]
Post subject:  Re: LMC Era Component Cross-Use

The last two of Manchester Corporation's 1967 Daimler Fleetlines (4759/60) had Leyland pneumocyclic gearboxes with direct-air changes. 'The Manchester Bus' (Eyre & Heaps) adds "when new", but I don't know if this is meant to imply that they didn't stay the course. My failing memory is trying to convince me that the pedestals were mounted on the right, but I wouldn't entirely trust it after all this time.

Author:  Bruce A. MacPhee [ Sun Dec 27, 2015 9:50 pm ]
Post subject:  Re: LMC Era Component Cross-Use

Introduced in 1961 for the Mercury, D197 had selectors mounted on the top face of the gearbox, with a short extension shaft to the change-speed box mounted on the flywheel housing; a casual observer might have mistakenly thought that the gear-lever, which curved forward from behind the engine, was directly mounted on the gearbox. When adapted for Badger / Retriever, Leyland re-designed the selectors and cover to bring the control tube to the right-hand side, giving a straight run for the extension tube to a change-speed box on the side of the crankcase. For Ergomatic AECs, the original design was simply rotated clockwise by one bolt-hole on the flywheel-housing to achieve the same result. 36-foot "Mediumweight" Reliances had their gearboxes rotated one bolt-hole in the opposite direction, bringing the control left of centre; presumably, this was to make the bracketry common with Reliance 590, whose ZF boxes had their control arms on the left.

I was interested to read that Southdown was one of only two "open market" operators to have synchromesh Bristol REs; if the last coaches with this box were "F" registered, Southdown's service saloons 430-449 (NUF430-449G) must have been last of all. They would also have been very unusual among 36-footers in having 6HLW engines - with the economy setting of 107 bhp! The earlier batch 210-249 were short models but with the same driveline. The first ten had Borg & Beck clutches and the rest had Bristol's own (all air-assisted), which gave no end of trouble.

Author:  cav551 [ Mon Dec 28, 2015 12:57 pm ]
Post subject:  Re: LMC Era Component Cross-Use

WFN 513 an East Kent 2MU3RV currently has a D197 box installed. This is vertical with the remote linkage running over the top of the AH470.

Author:  Bruce A. MacPhee [ Mon Dec 28, 2015 10:28 pm ]
Post subject:  Re: LMC Era Component Cross-Use

I wrote that 36-foot Mediumweights had the boxes rotated to the left. East Kent 513 is a 30-footer.
513 and many of that batch had their original D171 synchro boxes replaced by D197 boxes within a year of delivery; a fleet list incorrectly recorded them as being ZF boxes.

Author:  cav551 [ Tue Dec 29, 2015 12:04 am ]
Post subject:  Re: LMC Era Component Cross-Use

Thanks for that. It has altered the impression that the D197 had been fitted after withdrawal from service simply because the type of box was common in scrapyards and would fit.

Author:  Bruce A. MacPhee [ Tue Dec 29, 2015 10:42 am ]
Post subject:  Re: LMC Era Component Cross-Use

The conversion is not entirely straightforward! D197 is actually shorter than D171, requiring a longer propshaft. The splined clutch hub is different and D171 has a Spicer flange on the change-speed whereas D197 has a muff coupling. About 30 years ago, I had a Reliance (6MU4R7197) which had been subsequently fitted with a D171 and I converted it back to 6-speed again. I bought a perfectly good engine and gearbox - the later type with constant-mesh 1st and reverse (D397?) from a Marshal truck-mixer for £150; in those days, there was no demand for 505s and they were just weighed-in.

Author:  Bruce A. MacPhee [ Fri Jan 08, 2016 11:17 am ]
Post subject:  Re: LMC Era Component Cross-Use

Within the LMC era, and in addition to D197, other components "cross-used" were the Leyland gearboxes from the 1960 "heavy" range, e.g: GB128, GB130, adapted for Scammell Himalayan dumpers, replacing, I believe, ZF units.
The synchro gearbox for the Albion Lowlander was an adaptation of the Leyland GB83 box which had itself been modified from the GB63 of the early PD2 with the deletion of synchromesh on 2nd. 1st and 2nd were now engaged by dogs, whereas the old GB63 "synchro-2nd" box had a sliding-mesh 1st gear. Lowlander's box differed from Leyland's modified design only in the first-motion shaft and front bearing arrangement to suit independent mid-mounting, rather than being bolted-up to the engine.
To my knowledge, Leyland never published a drawing of the modified synchro (3rd + top) box, fitted to just about all manual Titans from 1955 onwards and most Leopards. Workshop Manuals of even the latest Titans still showed the old "synchro-2nd" type. Lowlander production was only a fraction of Titans, let alone Leopards, but Albion, in contrast to Leyland, went to the trouble of publishing an exploded drawing of the synchro box in their Parts List.
Incidentally, Leyland spec sheets for post-1954 Titans were inaccurate, quoting a 1st gear ratio of 4.95 to 1 and stating that 2nd and 3rd were helical gears; in fact, 1st gear was 4.89 to 1 and all forward gears were helical.

Prior to the "LMC era", Scammell's "Articulated 8-Wheeler" (soon to be named "Highwayman") could be specified with Leyland or Gardner engines, where the choice had previously been between Gardner and Meadows.
There was, of course, sharing of Leyland engines and Albion gearboxes between these two makes. For some reason, Leyland gave their own designations for Albion boxes used in Leyland chassis: the Albion GB236 in a Tiger Cub was a GB108, yet on chassis build-sheets, the Albion designation GB236 was used!

Author:  Stephen Allcroft [ Sat Jan 09, 2016 4:19 pm ]
Post subject:  Re: LMC Era Component Cross-Use

Thinking of Southdown and Luton manual RELLs and RESLs I wonder what transmission was fitted to ONI300? Although this 55 seat bus on RELH6G was registered in 1969, the chassis had been assembled from a CKD kit in the Irish Republic before it was dispatched to Scarborough for a Derwent II body. It later became GEM884N in the UK running for a number of independents.

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