475:
spare engine 'float' . The L60 reliability problem would have been far worse had it not been for the removable engine pack, which usually allowed a vehicle to be operational again with a replacement engine within a couple of hours of breaking down. A persistent source of trouble was the failure of the cylinder liner sealing resulting in coolant leakage into the cylinder bore. Fan drive belts overstressed fan bearing housings in the crankcase leading to cracking. Reliability did improve over time with modifications and improvement programmes, such as the "Sundance" programme which also improved power output. Sundance was carried out in five main phases between 1976 and 1979. Sundance had been preceded by "Dark Morn", "High Noon", and the initial "Fleetfoot" engine development programme -the person responsible for the choosing of
458:
133:
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24:
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compared to a four-stroke engine, and with the resulting difficulty in choosing the correct gear required for the particular driving task, trainee drivers tended to under-rev the engines and use inappropriate gear selections, leading to great difficulty climbing gradients, and when the
Chieftain Mk 1
442:
analysis of previous tank battles that concluded that a likely future tank battle would last no longer than two hours and so the most demanding requirement expected for any tank engine during wartime would be for it to be run at full power for this total amount of time only and so it would then be
926:
When installed in the early
Chieftains with L60s of around 600 bhp the initial TN12 gearbox design suffered from overheating and proved insufficiently robust, having been designed for a vehicle of lower weight and power. The overheating was cured by increasing the oil flow and fitting a heat
474:
The initial production L60 units were, at 585 bhp at 2,100 rpm, down on the designed initial power of 600 bhp and were plagued with reliability problems. These problems were exacerbated during the
Chieftain's introduction by initially an inadequate spares stock and an insufficient
662:
In 1975 all
British Chieftains were brought up to Chieftain Mark 5 standard as part of the "Totem Pole" programme which included the fitting of all vehicles with the 750 bhp L60 Mark 8A. On undergoing "Totem Pole" upgrades Chieftain Mk 2 vehicles were re-designated the Mark 6. Mk 3 vehicles
882:
The increased reliability that "Sundance" provided however allowed other problems to emerge that had not made themselves felt before, such as the draining of oil from the upper-crankshaft bearings when the engine stood for long periods, requiring the operators to crank the engine for 20 seconds
399:
One of the reasons the L60's unusual configuration was chosen was so as to obtain as compact a power plant as possible so allowing the height of the vehicle to be kept as low as was practicable, a requirement for the
Chieftain's design philosophy which was also seen in the recumbent driver's
391:. Both Tilling-Stevens and Leyland produced single-cylinder prototype engines for the tank engine project and by 1959 the resulting complete engine design had become the Leyland 60, or L60, with the first engine running that same year.
387:, and possessed good cold-starting characteristics. Some technical assistance was provided to Leyland by Rolls-Royce, who by that time was a parent to the Napier aero-engine company, Napier itself remained a subsidiary of
683:. The gearbox was semi-automatic foot-operated and had six forward, and two reverse gears. Like the engine, it was designed to be quickly replaceable. The TN12 had originally been developed for the cancelled
586:, new cylinder block with re-positioned fan belt deflectors, re-designed liners, new radiators, Belzona sealant used on liner seals, increased power to 720 bhp. For Chieftain Mk. 5, Mk. 3/2 and Mk 3/3.
873:
i.e., meaning a stock of spare engines available for immediate fitment to broken-down vehicles. Initial
Leyland L60 production was earmarked for new vehicles being built at the factories.
860:
The context here is a battlefield possibly contaminated by nuclear, biological, or chemical (NBC) weapons, and with personnel not protected by being inside vehicles having to wear
927:
exchanger, while the gearbox itself was redesigned to make it stronger, the resulting increase in gearbox size making it necessary to relocate the previously internal engine bay
596:
liner material, new pistons, increased power to 750 bhp. Used in
Chieftain Mk 5, the last Chieftain production variant. Later Marks were upgrades of existing vehicles.
450:
workshops rather than 'in the field', the engines being exchanged between vehicles and workshops as-and-when required. This philosophy was also applied to the contemporary
556:, de-rated Mark 4A2 for Vickers MBT/Vijayanta which was some 17-18 tons lighter than Chieftain. In this vehicle the L60 suffered fewer reliability problems. 540 bhp
345:
The initial engine choice in 1954 for what was known at the time as "Medium Gun Tank No.2", later designated the "FV4201" and given the service name 'Chieftain', was a
883:
before starting from cold, and rectification measures such as fitting non-return valves to prevent the oil draining back to the sump were only partially successful.
498:
Final production engines produced 750 bhp (560 kW) following a series of modifications to engines in service under the various improvement programmes.
602:, June 1977 "Dark Morn" modifications including new liner material, new pistons and piston rings with improved oil cooling, new fan drives, 750 bhp.
487:
in 1978. With the final rectification of most of the L60's previous reliability and power problems, vehicle availability levels rose to 80%. In the 1990
383:
This configuration, apart from being well-suited to multi-fuel use, also had the advantages of being of simple design with a low parts count, had low
361:
834:
Design target for the L60 was actually 600 hp for initial engines, 700 hp with development, the latter programme being carried out under the
901:
Mark 11A engines and Mark 13A engines had a three-lobe scavenger blower, Mark 12A engines and Mark 14A engines a two-lobe scavenger blower.
818:
608:, export version of Mark 9A with two-lobe scavenger blower. Mark 10A engines had additional air cleaning for the desert environment in
435:
Armoured Repair
Vehicle, which had been designed for this purpose and a complete engine change took around one-and-a-half, to 2 hours.
447:
732:(DERV) but on exercise would also be operated on Avgas (petrol), Avtag, Avtur (jet fuel), or whatever was available, e.g., domestic
536:, first production variant, January 1965, producing 585 bhp. Used in Chieftain Mk 1 which were used for training duties at
688:
864:
at all times. In these conditions, any involved or intricate work outside, on an engine or other system, is simply not possible.
443:
advantageous for it to be removed from the vehicle after the battle and exchanged for a fresh engine within a minimum of time.
1012:
592:, two-lobe scavenger blower, commercial version for general sale to customers other than the British Army of Mark 7A, new
357:
capability. This left the Rolls-Royce engine an unsuitable option and so a new engine with this capability was required.
88:
984:
60:
1125:
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107:
407:, a 19-litre diesel engine being expected to be capable of around the same power as the 600 hp 27-litre petrol
1135:
991:
634:, introduced March 1978, increased power to 750 bhp. Target 4,000-mile engine life achieved by December 1978.
67:
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MB837, an 8-cylinder multi-fuel engine of approximately the same power as the L60. The engine was trialled in an
1079:
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368:, was asked to develop an opposed-piston two-stroke diesel of similar design to those previously produced by
74:
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415:, necessary in a large two-stroke diesel for evacuating the cylinders of exhaust gases, was performed by a
41:
980:
56:
728:
NATO later rescinded this requirement. As events turned out, in service the L60 was normally run on
566:, pressure-lubricated fan bearings, 650 bhp, introduced in April 1969 for the Chieftain Mk. 3.
495:
tank which had by that point replaced
Chieftain, using more-conventional four-stroke V12 diesels.
958:
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736:. The L60 would run without preparation on any fuel, or combination of fuels, of sufficient
506:
was first introduced some drivers had difficulty climbing the vehicle onto the trailers of
384:
168:
137:
Leyland L60 engine pack with one of the radiators in the raised position displayed at the
8:
1005:
644:, August 1979 designations for modified Mark 11A and Mark 12A engines using no O-ring on
346:
181:
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81:
582:, produced from October 1971, culmination of initial "Fleetfoot" development programme,
501:
Initially, due to unfamiliarity with the two-stroke engine's different exhaust note and
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1098:. Director of quality assurance (fighting vehicles and engineer equipment). 1966.
1056:. Director of quality assurance (fighting vehicles and engineer equipment). 1966.
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providing "regenerative" steering, a derivative of the system first used on the
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The
Chieftain's L60 engine and cooling system were designed into an integrated
353:
introduced a policy in 1957 requiring all armoured fighting vehicles to have a
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The intended estimated design weight for FV4201 was at this time 47 tons
745:
658:, April 1980 re-designations of Mark 11A/N - Mark 12A/N engines, 750 bhp
269:
191:
822:
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483:. The Sundance programme was the subject of parliamentary questions in the
480:
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622:, "Sundance" modifications to fix reliability issues, block/liner sealing
733:
729:
705:
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The requirement for an easily changeable engine pack was the result of a
330:
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550:, Mark 4A with a new piston crown, produced 650 bhp, November 1965
502:
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This would also allow the engines to be worked on in properly equipped
377:
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211:
778:'s (Jumo's) opposed-piston diesel aircraft engine designs such as the
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was a British 19-litre (1,200 cu in) vertical six-cylinder
254:
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Chieftain AARV and CHAVRE availability levels exceeded those of the
23:
861:
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365:
817:
Rolls-Royce would use the opposed-piston two-stroke design in its
576:, 650 bhp. Fitted to Chieftain Mk. 3(S) « Sandman »
1096:
TANK, COMBAT, 120-mm GUN, CHIEFTAIN, ALL MARKS USER HANDBOOK 1966
1054:
TANK, COMBAT, 120-mm GUN, CHIEFTAIN, ALL MARKS USER HANDBOOK 1966
928:
737:
286:
650 brake horsepower (480 kW) at 2,100 rpm (L60 No.4, Mk 4A)
298:
1,460 lb⋅ft (1,980 N⋅m) at 1,320 rpm (L60 No.4, Mk 4A)
687:. A scaled down version of the TN12, the TN15, was used in the
623:
293:
432:
431:
which could be changed "in the field" using the crane of an
1071:
851:
was a complicated procedure that took around twelve hours.
609:
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350:
362:
Fighting Vehicles Research and Development Establishment
757:
facing the same requirement West Germany developed the
626:
retained by interference-fitted liners, new injectors,
349:
diesel V8, however during the Chieftain's design phase
910:
The gearbox used a steering system devised in 1935 by
663:
became the Mk 7, and Mk 3/3 vehicles became the Mk 8.
411:
whilst taking up less room in the engine compartment.
403:
The use of the two-stroke cycle allowed for a greater
765:
before the NATO multi-fuel requirement was cancelled.
562:, modified piston with oil cell and offset bowl, new
931:
to an armoured external box at the rear of the hull.
972:. Unsourced material may be challenged and removed.
48:. Unsourced material may be challenged and removed.
847:By comparison changing the engine on the earlier
1107:
892:The L60 utilised a piston with a separate crown.
774:The Napier company had earlier licensed some of
572:, produced October 1970 featuring a two-stage
288:750 brake horsepower (560 kW) (L60 MK 7A)
380:engine being particularly highly regarded.
360:Leyland Motors, under the direction of the
131:
1032:Learn how and when to remove this message
108:Learn how and when to remove this message
530:engines completed 1959 to 1965, 60 built
456:
120:Reciprocating internal combustion engine
329:(MBT). The engine was also used in the
1108:
322:in the late 1950s/early 1960s for the
333:and its Indian-built derivative, the
970:adding citations to reliable sources
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46:adding citations to reliable sources
17:
479:apparently being an admirer of the
13:
914:, then-Director of Tank Design at
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186:19 litres (1,200 cu in)
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957:needs additional citations for
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33:needs additional citations for
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405:power for a given displacement
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671:The engine was mated with a
206:146.1 mm (5.75 in)
196:117.5 mm (4.63 in)
173:six-cylinder, twelve-piston
7:
584:three-lobe scavenger blower
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10:
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318:diesel engine designed by
1126:Two-stroke diesel engines
1068:The Chieftain Tank Engine
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1136:British Leyland engines
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685:FV300 light tank series
241:Roots (scavenge blower)
1131:Opposed piston engines
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632:Poly-V fan drive belts
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740:value and low enough
460:
175:opposed-piston engine
139:Bovington tank museum
966:improve this article
776:Junkers Motorenwerke
744:to pass through the
691:series of vehicles.
675:triple-differential
454:series of vehicles.
42:improve this article
862:protective clothing
825:series of vehicles.
510:tank transporters.
673:Merritt-Brown TN12
542:Catterick Garrison
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409:Meteor tank engine
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677:epicyclic gearbox
508:Thornycroft Antar
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485:House of Commons
389:English Electric
327:main battle tank
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701:Chieftain tank
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681:Churchill tank
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630:fuel filters,
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538:Bovington Camp
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320:Leyland Motors
310:opposed-piston
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1022:February 2021
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983: –
982:
981:"Leyland L60"
978:
977:Find sources:
971:
967:
961:
960:
955:This article
953:
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944:
943:
930:
923:
917:
913:
912:H. E. Merritt
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385:bearing loads
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294:Torque output
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202:Piston stroke
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192:Cylinder bore
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169:Configuration
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59: –
58:
57:"Leyland L60"
54:
53:Find sources:
47:
43:
37:
36:
31:This article
29:
25:
20:
19:
16:
1121:Tank engines
1095:
1090:
1067:
1062:
1053:
1048:
1028:
1019:
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1002:
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976:
964:Please help
959:verification
956:
922:
906:
897:
888:
878:
869:
856:
843:
838:"Fleetfoot".
830:
813:
804:
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759:Daimler-Benz
753:
724:
670:
667:Transmission
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589:
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514:L60 variants
500:
497:
493:Challenger 1
481:Western film
473:
445:
440:British Army
437:
426:
417:Roots blower
402:
398:
382:
359:
344:
305:
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282:Power output
270:Water-cooled
237:Turbocharger
182:Displacement
152:Manufacturer
104:
95:
85:
78:
71:
64:
52:
40:Please help
35:verification
32:
15:
734:heating oil
730:diesel fuel
706:Vickers MBT
594:shot-peened
574:air cleaner
470:Performance
429:engine-pack
423:Maintenance
364:(FVRDE) at
347:Rolls-Royce
341:Development
331:Vickers MBT
306:Leyland L60
126:Leyland L60
1110:Categories
1081:010248578X
1070:. London:
992:newspapers
938:References
819:K60 engine
763:M47 Patton
642:Mark 12A/N
638:Mark 11A/N
503:power band
477:code names
413:Scavenging
400:position.
378:Commer TS3
355:multi-fuel
316:multi-fuel
313:two-stroke
255:Oil system
231:Combustion
212:Valvetrain
68:newspapers
849:Centurion
836:code name
746:injectors
742:viscosity
738:calorific
711:Vijayanta
528:prototype
463:Chieftain
335:Vijayanta
324:Chieftain
246:Fuel type
216:valveless
98:June 2017
1074:. 1978.
656:Mark 14A
652:Mark 13A
620:Mark 12A
616:Mark 11A
606:Mark 10A
548:Mark 4A2
489:Gulf War
395:Overview
366:Chertsey
259:dry sump
146:Overview
1116:Engines
1006:scholar
600:Mark 9A
590:Mark 8A
580:Mark 7A
570:Mark 6A
560:Mark 5A
554:Mark 4B
534:Mark 4A
82:scholar
1078:
1008:
1001:
994:
987:
979:
797:Rootes
689:CVR(T)
624:O-ring
524:Mark 4
520:Mark 1
370:Napier
276:Output
249:Diesel
163:Layout
84:
77:
70:
63:
55:
1013:JSTOR
999:books
823:FV430
717:Notes
452:FV430
433:FV434
89:JSTOR
75:books
1076:ISBN
1072:HMSO
985:news
610:Iran
564:sump
540:and
461:The
448:REME
372:and
351:NATO
304:The
226:16:1
61:news
968:by
695:Use
628:CAV
526:,
44:by
1112::
654:-
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1084:.
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1029:(
1024:)
1020:(
1010:·
1003:·
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