Volvo MD5A Workshop Manual
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Volvo MD5A Workshop Manual

Volvo MD5A Workshop Manual

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

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Summary of Contents for Volvo MD5A

  • Page 1 Publ. No. 3061 Dec. 1975 WORKSHOP MANUAL MD5A Marine diesel engine ENGINE UNIT...
  • Page 2 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.

  • Page 3: Table Of Contents

    CONTENTS Presentation Dismantling Electrical system, thermostat housing cylinder head Flywheel, fuel injector pump Oil pump, transmission cover, governor Lubricating oil pump, camshaft, cylinder Crankshaft, cylinder liner, camshaft bearing Overhauling Lubricating oil pump, sea-water pump 7 – 9 Feed pump 9 – 11 Fuel filter, crankshaft Centrifugal governor, piston 12 –...

  • Page 4: Presentation

    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.

  • Page 5: Electrical System, Thermostat Housing Cylinder Head

    Repair instructions Dismantling 1. Drain the cooling water and the oil from the engine. Clean 3. Remove the rocker cover and the fuel pipe between the externally afterwards. Loosen the water hose between the pump and the injector and unscrew the rocker gear. Note! gearbox and the sea -water pump and remove the gearbox.

  • Page 6: Flywheel, Fuel Injector Pump

    5. Remove the flywheel nuts. Spanner jaw width 55 mm 7. Remove the cover for the injection pump. Note! The (2 5/32”). Use a wooden shaft or something similar as a bracket for the cold start is fixed with one of the screws. counter force in the flywheel spokes.

  • Page 7: Oil Pump, Transmission Cover, Governor

    9. Remove the pump screws. Position the ball in the centre 11. Remove the governor by loosening the hexagonal set and remove the pump. screw (1), the governor and the gear wheel can then be withdrawn. 10. Remove the sump and then the transmission cover (13 Remove the screw and the locking washer for the screws).

  • Page 8: Lubricating Oil Pump, Camshaft, Cylinder

    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 16.

  • Page 9: Crankshaft, Cylinder Liner, Camshaft Bearing

    17. Remove the main bearing caps. Take care of the axial 19. Bearing replacement. Press out the camshaft bearings if thrust bearings 1 on the transmission side. Lift the crankshaft they are damaged or if the wear is too great (see technical out and the bearing shells afterwards and then the axial data).
  • Page 10 21. Remove the steel wire which holds the filter. Remove Overhauling the sea-water pump and clean the wire gauze thoroughly. Afterwards remove the 23. The sea-water pump is a round flange type pump which six screws which hold the cover in position. Discard the means that it can be fitted in a position best suited to the gasket.

  • Page 11: Feed Pump

    25. Unscrew the screw and withdraw the impeller from the 27. Fit new sealing rings. Note! The sealing rings must face shaft. If the sealing rings are to be replaced, the shaft and the right way, see that they do not block the drain hole in the the impeller can be removed and the screw subsequently pump housing.
  • Page 12 29. Remove the cover’s centre screw, remove the filter 1 31. Depress the diaphragm and shake the pump arm and clean it. spindle out until the pump arm is free. Then remove the diaphragm from the housing. 30. Remove the six screws which hold the upper and lower 32.

  • Page 13: Fuel Filter, Crankshaft

    Crankshaft 33. Clean the pump housing carefully and replace worn 35. Remove the circlip with circlip pliers. Then remove the parts. Refit the manual pump arm. Press in the diaphragm gear drive. Use a press or a gear puller. Clean the and connect the pump arm to the diaphragm centre pin.

  • Page 14: Centrifugal Governor, Piston

    Centrifugal governor 37. Clean the governor. Check to see if the weights 2 grip 39. Mark the piston and the connecting rod. Remove the on their spindle or if there is too much movement between circlips. Press out the gudgeon pin with a drift. (The piston the spindle and the governor weight.
  • Page 15 41. Knock new screws in place and press a new bush in the 43. Fit the piston rings with the help of piston ring pliers. connecting rod. Ensure that the lubricating hole 1 in the bush Start with the oil scraper ring in the lowest groove. The oil aligns with the hole in the connecting rod.

  • Page 16: Valve Guides, Nozzle Sleeve

    Replacing valve guides Nozzle sleeve 45. The valve guides must be replaced if there is too much 47. Remove the injector sleeve with tool 884541. Insert the play between the valve stem and the valve guide. (See expanding screw in the nozzle sleeve and screw anti-clock- technical data.) Press out the valve guides with tool 884538.

  • Page 17: Valves, Valve Seats, Rocker Mechanism, Injector

    49. Lubricate the mandrel tool 884537 and insert the tool Valve and valve seat grinding into the sleeve. (Ensure that the centre screw is sufficiently 51. Machine the valve seats by milling or grinding them. unscrewed.) Place some nuts or several washers on the Grind no more than is necessary to give the seat the correct studs so that the yoke can be tightened in place with the shape and a good mating surface.
  • Page 18 53. Check the wear on the rocker shaft. Also check that the Pressure testing the nozzles tappet adjustment screw’s spherical part is neither deformed 55. Check the shape of the jets at an opening pressure of nor worn. The threads on the screw and the locknut must be 185 kp/cm (2631 p.s.i.).

  • Page 19: Hand Start Mechanism, Camshaft

    Flywheel cover and hand starting mechanism that the transmission cover must be machined since the 57. Unscrew nut 1 and remove it and washer 2 holding the new camshaft gear is thicker than the earlier gear and hand starting gearwheel 3. Then remove the gearwheel from consequently there is not enough space for it in the the shaft A.

  • Page 20: Assembling

    ASSEMBLING 63. Place the main bearing halves with the oil channel holes 61. Check that the liner is not scratched and that it is in in the block. Then place the axial bearing halves in position. good condition otherwise. Fit new 0-rings 1 in the block (2 Turn the oil grooves 1 outwards.

  • Page 21: Cylinder, Camshaft, Governor

    65. Remove any wear edges in the cylinder liner. Oil the 67. Fit the camshaft with the camshaft gear. Align the marks cylinder liner and fit the piston in the block. Use a piston ring on the crankshaft gear and the camshaft gear. sleeve or tool 9992176.

  • Page 22: Lubricating Oil Pump, Transmission Cover

    69. Fit the gearwheel on the camshaft’s opposite end. 71. Fit a new gasket for the transmission cover. Afterwards fit the transmission cover. Fix the lifting eye with the upper screw. Adjustment of control rod travel 72. Fit a new gasket and fit the injector pump. Press on the ball end of the control arm.
  • Page 23 73. Release the plunger 8 mm (0,3150 in.) and measure the 75. If the engine smokes abnormally, the centre screw on distance from the transmission cover face to the adjusting the cover can be loosened and the adjusting screw can be screw’s contact point on the control arm.

  • Page 24: Oil Sump, Cylinder Head, Feed Cover

    77. Fit a p lane packing and then fit the sump. Note! On 79. Replace the tappet rods and fit the rocker mechanism. earlier engines a rubber seal was used. This is to be Check that the guide pin in the cylinder head goes into the replaced by a plane packing.
  • Page 25 81. Fit the fuel filter. Place sealing rings on both sides of the Connect the injector pipe, the temperature and oil fuel pipe unions. pressure transmitters. Thermostat testing 82. Fit the injector. The tightening torque = 10 Nm (1 kpm) 84.

  • Page 26: Flywheel, Generator, Valve Adjustment

    85. Place the key for the gearbox connecting drive on the 87. Fit the starter motor and the alternator. Note! Place the crankshaft on the gearbox side. Heat the connecting drive spacer tube correctly and assemble the belt tensioner. Fit and fit it onto the crankshaft.

  • Page 27: Checking Injection Angle

    91. Open the level valve 1 on the measuring apparatus so INJECTION ANGLE CONTROL that the level lies 25 - 30 mm (1” - 2 3/16”) from the bottom. 89. A Wilbär tube is used when checking the injection angle. Turn the engine in the rotation direction until compression is Fit the Wilbär tube on the pressure pipe nipple.

  • Page 28: Bleeding The Fuel System, Electrical System

    Fit the exhaust elbow and the gearbox. Use new ELECTRICAL SYSTEM gaskets. Check that the rubber damper is not damaged. IMPORTANT The following applies to engines fitted with alternators: 1. Do not break the electrical circuit between the alternator and the battery when the engine is running. If a main switch is fitted it must therefore not be turned off until the engine is stopped.

  • Page 29: Wiring Diagram

    Wiring Diagram Cable Marking Designation Colour A.W.G. Circuit explanation White Extra switch Black Charging control lamp B’ Black Temperature warning lamp B” Black 0.75 Oil pressure warning lamp Key switch C’ Warning unit C” Screw Yellow Charging control lamp (for secondary battery Brown circuit, extra equipment) H’...

  • Page 30: Fault-Tracing System

    FAULT TRACING The fault finding chart given below only covers the most common faults which occur. FAULT Note Main switch not connected, flat battery, cable See para A disconnected. Empty fuel tank, fuel tap closed, blocked fuel See para B filter.

  • Page 31: Special Tools

    Special tools for the MD5A Part No Designation 884538 Drift for pressing out valve guides 884549 Drift for pressing in valve guides 884557 Drift for pressing in injector sleeve. 884541 Tool for removing injector sleeve. 884537 Drift for copper sleeve.

  • Page 32: Technical Data

    TECHNICAL DATA General Type designation Effect (DIN) at 40 r/s (2500 r.p.m.) MD5A No. of cylinders 5.5 kW (7.5 b.h.p) Bore Stroke 84 mm (3.31 in.) Displacement, total 80 mm (3.15 in.) Compression ratio 0,443dm (27 cu. in.) Compression pressure at starter motor speed...
  • Page 33 Engine oil capacity inc. filter (Imp. qts. = US qts.) 2,1 din (1.8 = 2.2) Oil quality according to API system (DS) 1st alternative. Above + 10 C (5Q0 F) Volvo Penta oil Double grade SAE 20W/30 Below + 10 C (50 F) Volvo Penta oil Single grade SAE l0W 2nd alternative.
  • Page 34 Lubrication oil filter Designation MANN W 77 or FRAM PH3614 Lubrication oil pump Type Gear pump Spring for pressure reduction valve: Length unloaded mm (in.) (1.5748) Loaded with 25 N (2,5 kp) (5,5 lb) mm (in). . (1.3386) Loaded with 35 N (3,5 kp) (7,7 lb) mm (in.) . 31,5 (1.2402) Gear’s axial clearance including packing mm (in.)
  • Page 35 TIGHTENING TORQUES Cylinder head nuts* 70 Nm (7 kpm) (50Lbft.) Cylinder head studs 20 Nm (2 kpm) (14Lbft.) Screw for a gearbox drive on crankshaft 80 Nm (8 kpm) (58 Lbft.) Flywheel nut 500 Nm (50 kpm) (362Lbft.) Big end (connecting rod) bearings 70 Nm (7 kpm) (50Lbft.)

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