ECHIVICIAINI'S TIPS
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Julian Jones, pictured setting the pre-tension on an injector, is a familiar figure to many Volvo technicians. He has been busy taking the FH introduction and familiarisation courses and those on stripping/rebuilding the D12A engine. Jones spent five years with Volvo dealer Lee Line Commercials in Dorchester before moving to Warwick to work as a breakdown co-ordinator with Action Service Europe.
Two and a half years ago he moved to the training department; he is a Institute of Training and Development qualified instructor.
1 The front journal of the overhead camshaft is marked with numbers 1-6 while those with VEB (recognised by the large exhaust rocker) have V1—V6 markings too. With non-VEB engines look at the number on the camshaft that is opposite the pointer and set the inlet (0.2mm), exhaust (0.5mm) and injector pre tension (0.75mm) on that cylinder. First the cross shaft must be set by pushing it down lightly onto the valve farthest from the camshaft and screwing the adjuster screw down until it touches the top of the valve. Then turn a further 60° (one flat) and tighten the locknut. Non-VEB engines have exhaust cross shafts similar to those on the inlet, 2 On VEB engines only set the inlet and injector pre tension (back off adjuster, set DTI to 0.75mm on spring collar and then screw adjuster in until DTI reads zero—lock locknut) against the cylinder number. To set the exhaust, align the V number on the camshaft
. and set that cylinder. Having first set the cross shaft, push the rocker arm up against the leaf spring (bolted to corn bearing cap) and insert feeler between cross shaft and rocker arm. The prescribed gap is 1.6mm with a 0,05mm tolerance either way. If it is out of tolerance by unscrewing the adjuster completely, the shims can be removed.
3 The single disposable canister-type fuel filter should be changed on the basic and annual services. First unscrew the 'drain' valve on the filter housing to drain the fuel rail. Remove and replace the filter in the normal way (lubricate the seal and Fit hand tight). To bleed the system tighten the 'drain' valve and loosen the adjacent 'vent' valve. Using the priming pump expel all the air and close the 'vent' valve. Then loosen the valve in the fuel rail at the rear of the engine (indicated) and continue pumping until all air is expelled. On restart the engine may run roughly for a minute or two while the electronics settle down. 4 A 50% antifreeze
concentration is required in the coolant in latest 12-litre engine which is also fitted with a coolant filter. The disposable canister type filter contains inhibitor and should be changed every six months. Before removing the filter with a strap wrench, turn the tap (indicated) off by moving the lever to the horizontal position. Lubricate the seal and screw the filter on handtight—don't forget to turn the tap back an. Every four years the coolant should be changed. If you use Volvo antifreeze, or any other with the required inhibitor pack, then the coolant filter should not be renewed at the some time as the coolant.
5 Assessing the lining/drum clearance, and through that if the automatic adjustment is working correctly, is done by measuring the stroke length. The required length is determined by cross referencing the chamber type with the lever arm length as shown below. These apply to all Z-cam braked Volvos.