Better torque in Mk III Leyland 500
Page 30
If you've noticed an error in this article please click here to report it so we can fix it.
• The Leyland 500 series range of trucks incorporating the Leyland-built Lynx, Bison, Buffalo and Super Buffalo models has been facelifted and the chassis specification improved with the introduction of the Mk III designation.
The turbocharged Leyland 510 engine now uses a SIGMA fuel pump and a Garrett AiResearch turbocharger in place of the previous Simms/Holset equipment. These changes, together with reworked valve gear, Leyland claims give the engine better torque characteristics and lower smoke-emission levels. Maximum torque is now achieved at 1300 rev /min compared with the 1500 rev! mitt of the previous series. There are no changes to the naturally aspirated 500 engine as specified on the Lynx and Bison.
Engine cooling has been improved by the use of a remote header tank. A feed is taken from this tank direct to the eye of the water pump, which, it is claimed, maintains -a smooth water flow.
Front engine mountings have been made more robust and those at the rear have been repositioned thus making it easier to remove the gearbox while at the same time giving a better degree of vibration insulation.
Behind the cab a new full width gantry has been specified as standard carrying the air inlet parallel to the vertically installed exhaust.
The Mark III versions of the Bison and Buffalo now feature a Lipe Rollway I4in. diameter twin-plate clutch to be used with the Fuller RIO 609 gearbox. These replace the previously used Thornycroft D245 gearbox and the Borg and Beck I 7in. diameter single plate clutch. Existing axles of the Leyland hub-reduction type will be used throughout.
The internal noise level has been improved by some 2dB(A) by the adoption of a double-skinned sheet metal engine cover filled with loose glassfibre. An improvement in elbow room for both the driver and mate is achieved by lowering the engine tunnel 51-in. and moulding a rectangular recess into this engine cover which doubles as an oddment tray. Above the windscreen the same full-width document shelf and sun visors are now fitted as in the Marathon.
The door-hinge mounting brackets which have given rise to trouble in service are now
reinforced and anti-burst door locks and mirrors meeting the EEC requirements will be introduced by next June when the regulations come into force.
The new range now comprises:—
Lynx — 16T rigid, 261 articulated; Bison — 22T rigid, 24T rigid; Buffalo — 16T rigid, 32T articulated; Super Buffalo — 22T rigid, 24/32T articulated.