Volvo Penta MD5A Marine Diesel Engine Workshop Manual

Publ. No. 3061 Dec. 1975 WORKSHOP MANUAL MD5A Marine diesel engine ENGINE UNIT

FOREWORD This workshop manual contains repair instructions for the MD5A marine diesel engine. The instructions concerning overhauling describe the most suitable working method to be used with the special tools listed under the heading “Special tools”. Both the engine designation and its serial number must be clearly stated in all correspondence concerning the engine and when ordering spare parts. We reserve the right to carry out design modifications and, for this reason, the contents of this manual cannot he regarded as binding. NEW UNITS OF MEASUREMENT Technicians have long since tried to establish an internationally standardized system of measurements. In 1960 a decision was made to use a system called SI (Systéme International d’Unites). To a large extent, this system is based on earlier systems but the units have been made uniform so that no conversions are necessary. The SI-system is now being applied within industry in Europe, This manual contains the new SI- units. The units used previously however, are also stated but in brackets. The new units are: Output is slated in kW (kilowatts) earlier unit h.p. (horsepower) Torque is stated in NM (Newton-metres) earlier unit kpm (kilopond-metres) Engine speed is stated in r/s (revolutions per second) earlier unit r.p.m. (revolutions per minute) Displacement and volumes are stated in dm 3 ( cubic decimetres) earlier unit l (litres) Pressure is stated in Pa (Pascal) earlier unit kp/cm 2 (kiloponds per square centimetre). Reproduction permitted if source quoted

CONTENTS Presentation 2 Dismantling Electrical system, thermostat housing cylinder head 3 Flywheel, fuel injector pump 4 Oil pump, transmission cover, governor 5 Lubricating oil pump, camshaft, cylinder 6 Crankshaft, cylinder liner, camshaft bearing 7 Overhauling Lubricating oil pump, sea-water pump 7 – 9 Feed pump 9 – 11 Fuel filter, crankshaft 11 Centrifugal governor, piston 12 – 13 Valve guides, nozzle sleeve 14 – 15 Valves, valve seats, rocker mechanism, injector 15 – 16 Hand start mechanism, camshaft 17 Assembling Cylinder liner, crankshaft 18 Cylinder, camshaft, governor 19 Lubricating oil pump, transmission cover 20 Adjustment of control rod travel, assembling flywheel cover 20 – 21 Oil sump, cylinder head, feed cover 22 Fuel filter, injector, thermostat 22 Flywheel, generator, valve adjustment 24 Checking injection angle 25 Bleeding the fuel system, electrical system 26 Wiring diagram 27 Fault-tracing system 28 Special tools 29 Technical data 30 – 33

Presentation 1. Connection for hand start 2. Fuse box 3. Thermostat housing 4. Decompression lever 5. Injector 6. Oil filler Cap, engine 7. Water drain tap, gearbox 8. Oil drain plug, gearbox 9. Water drain tap, engine 10. Oil filler, gearbox 11. Sea-water pump 12. Dipstick, gearbox 13. Fuel filter 14. Bleed screw 15. Hand pump, fuel 16. Dipstick, engine 17. Oil filter 2

Repair instructions Dismantling 1. Drain the cooling water and the oil from the engine. Clean externally afterwards. Loosen the water hose between the gearbox and the sea -water pump and remove the gearbox. 3. Remove the rocker cover and the fuel pipe between the pump and the injector and unscrew the rocker gear. Note! Pull the rocker gear straight up since it is centred with a guide pin 1. The other hole 2 is an oil channel. 2. Remove the generator and its drive belt, starter motor, fuel filter and fuel pump with the drain-off pipe (be careful of fuel spillage), coolant water pump with hose and thermostat housing, dipstick, temperature and oil pressure sensors. Unscrew and discard the oil filter. 4. Remove the push-rods 1, remove the cylinder head and the cylinder head gasket. Take care of the washers 2 under the nuts. 3

5. Remove the flywheel nuts. Spanner jaw width 55 mm (2 5/32”). Use a wooden shaft or something similar as a counter force in the flywheel spokes. 7. Remove the cover for the injection pump. Note! The bracket for the cold start is fixed with one of the screws. Take care of the spring under the cover. 6. Fit tool 884078 to the flywheel. Afterwards screw in the centre screw on the tool until the flywheel loosens. 8. Prise the lower ball joint free from the pump with a screwdriver. 4

9. Remove the pump screws. Position the ball in the centre and remove the pump. 11. Remove the governor by loosening the hexagonal set screw (1), the governor and the gear wheel can then be withdrawn. 10. Remove the sump and then the transmission cover (13 screws). The lifting eye is fixed one of the screws. The cover is centralised by guide pins. 12. Remove the screw and the locking washer for the gearbox drive flange on the crankshaft and remove the flange with a puller. (Use counter force.) Remove the key afterwards. 5

13. Remove the lubricating oil pump. Discard the gasket. 15. Remove the gearwheel on the camshaft’s flywheel side (4 screws). Then remove the camshaft and the gearwheel. 14. Remove the cover (flywheel side), 10 screws. The cover is centred with guide pins. The screws by the guide pins are fitted with thick washers. 16. Mark and remove the bearing cap on the crankshaft and carefully knock out the piston through the cylinder. 6

19. Bearing replacement. Press out the camshaft bearings if they are damaged or if the wear is too great (see technical data). Clean the bearing housings and ensure that the oil channels are clean. Press in the new bearings so that the oil holes face the corresponding oil channels in the block. When the bearings are pressed in position they are to be reamed (see technical data). 17. Remove the main bearing caps. Take care of the axial thrust bearings 1 on the transmission side. Lift the crankshaft out and the bearing shells afterwards and then the axial bearing halves. 18. Mark the cylinder liner’s position in the cylinder so that the same position can be obtained during assembly. Remove the cylinder liner. Use tool 884551. Use the long screw and its nut from the tool 884231 (MD21-MD32). See page 29 Special tools. Discard the 0-ring. Afterwards remove the 0-rings in the block which provide a seal for the cylinder liner and then remove the valve lifters. Wash all the parts and replace those damaged. Oilpump 20. Remove the gearwheel’s nuts and pull off the gearwheel with a puller. The gearwheel sits on a key, take care of this key. 7

21. Remove the steel wire which holds the filter. Remove and clean the wire gauze thoroughly. Afterwards remove the six screws which hold the cover in position. Discard the gasket. Overhauling the sea-water pump 23. The sea-water pump is a round flange type pump which means that it can be fitted in a position best suited to the coolant water hoses. The new pump is fitted with an 0-ring which forms a seal against the engine. 22. Remove the gearwheel from the housing. Remove the split pin for the reduction valve. Remove washer 1, spring 2 and piston 3. Clean and replace damaged parts. Assemble the lubricating oil pump in the reverse order. Note! Fit a new gasket 4 between the housing and the cover. Fix the wire mesh 5 in position with the steel wire 6 and finally lay the key in position and tighten the gearwheel 7. 24. Remove the cover (6 screws). Change the impeller with the help of two screwdrivers or something similar. Note! Protect the edges of the pump housing. See the figure. Prise out the impeller with the screwdrivers so far that the screw becomes visible. 8

Volvo Penta MD5A Marine Diesel Engine Workshop Manual

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