Volvo Penta MD6A Workshop Manual
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Volvo Penta MD6A Workshop Manual

Volvo Penta MD6A Workshop Manual

Marine diesel engines
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Workshop Manual
A
2 (0)
Engine unit
MD6A, MD7A
AB Volvo Penta
Customer Support
Dept. 42200
SE-405 08 Gothenburg
Sweden

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Questions and answers

Paulina
March 13, 2025

A qunanto vanno regolate le valvole **** spessimetro?

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1 comments:
Mr. Anderson
March 13, 2025

The maximum clearance between the valve stem and guide for the Volvo Penta MD6A is 0.16 mm (0.0063”).

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Summary of Contents for Volvo Penta MD6A

  • Page 1 Workshop Manual 2 (0) Engine unit MD6A, MD7A AB Volvo Penta Customer Support Dept. 42200 SE-405 08 Gothenburg Sweden...

  • Page 2: Table Of Contents

    Workshop Manual Marine diesel engines MD6A, MD7A Contents Safety Precautions General information Repair methods Presentation MD6A MD7A Repair instructions Electrical system Special Tools Technical Data...

  • Page 3: Safety Precautions

    Check that the warning information decals on This workshop manual contains technical data, the product are always clearly visible. descriptions and repair instructions for Volvo Penta Replace decals that have been damaged or products or product versions contained in the contents painted over.
  • Page 4 Always use protective goggles where there is a Store oil and fuel-soaked rags and fuel and danger of pieces of metal, sparks from oil filters safely. In certain conditions oil- grinding, acid or other chemicals being thrown soaked rags can spontaneously ignite. Used into your eyes.
  • Page 5 (gasoline engines) and fuel system To ensure safe handling and to avoid on Volvo Penta products are designed and damaging engine components on top of the constructed to minimize the risk of fire and engine, use a lifting beam to raise the engine.

  • Page 6: General Information

    Use of non-original AB Volvo Penta spare methods introduced after the date of publication will parts will result in AB Volvo Penta being un- be provided in the form of Service Bulletins. able to assume liability for the engine meet- ing engine certification requirements.

  • Page 7: Repair Methods

    Take All procedures for which there are Volvo Penta spe- special care when working on-board, that oil and cial tools in this Workshop Manual are carried out us- waste is taken for destruction and is not accidentally ing these.
  • Page 8 Tightening using both a torque setting and a protractor angle In this Volvo Penta Service Manual the user will find requires that first the that each section where these agents are applied in recommended torque is applied...

  • Page 9: Presentation Md6A

    Presentation MD6A Recess for starting crank Oil filling, engine Sealed crankcase ventilation Intake silencer Connection, fuel inlet Feed pump Reduction reverse gear MS, red. 1.91:1 Control lever, reverse gear Oil filling, reverse gear 10. Oil pressure contact 11. Lubricating oil filter 12.

  • Page 10: Md7A

    MD7A Oil dip-stick and oil filling, reverse gear Cover, cooling water pump Bleed-screw, fine filter Fine filter Decompression handle Pressure pipe nut Temperature sender Injector Thermostat housing 10. Oil filling, engine 11. Hand start 12. Cooling water drain, engine 13. Fuel injection pump 14.

  • Page 11: Repair Instructions

    Repair instructions 3. Remove the thermostat housing (2 bolts) and the Drain the cooling water and oil from the engine. Then hose clamp under the housing. Take the clean the outside of the engine. Remove the reverse thermostat out of the exhaust manifold. Note the gear, 4 bolts.
  • Page 12 5. Remove the rocker arm cover (2 nuts), the intake 7. a. (BOSCH pump) Disconnect the pipe from the manifold (4 bolts), the rocker arm (2 nuts) and fuel filter and remove the nuts for the fuel the cylinder head (9 bolts). Take care of the injection pump.
  • Page 13 9. Remove the timing gear cover. NOTE! The small 11. Knock out the hand starter pin in the camshaft. round cover on which the fuel pump is mounted Remove the protective cover (2 bolts). NOTE! has bolts with 3 different lengths. The bolts for Scrap the sealing ring and fit a new one.
  • Page 14 13. Remove the sump as well as the nut and lock 15. Remove the bolt for the intermediate gear. Dis- washer for the camshaft. Use a counterhold on card the sealing washer 1 under the bolt. Pull off the crankshaft. the intermediate gear.
  • Page 15 17. Remove the gearwheel for the camshaft by tap- 19. Invert the engine and remove the oil strainer (2 ping the camshaft on the flywheel side with a bolts and 1 nut). plastic mallet or similar tool. Lift out the shaft and take care of the cover.
  • Page 16 21. Mark the connecting rod and cap nearest the fly- 23. Remove the centre nut and washer for the gear wheel with a peener. Peen as shown in Fig. 21. wheel on the lubricating oil pump. The shaft is ta- pered and the gear wheel sits on a key.
  • Page 17 25. Re-fit the gears as shown in the Fig. below. Fit 27. Check for wear on pistons, piston rings and gud- the cover together with a new gasket. Tighten up geon pins. Replace if necessary. The piston and the 4 bolts and rotate the shaft to make sure that connecting rod must be matchfitted as shown in it does not jam.
  • Page 18 Cylinder head 31. Replacing the valve guides. With excessive clearance between the valve stem and valve guide, the valve guide must be 29. Remove the valve tappets. NOTE! Carefully replaced. (See under “Technical Data”.) Press machine clean the valve tappets where they have been smoothed down (1) in order to serve out the valve guides with tool 884538.
  • Page 19 Place the cylinder head on its edge and fit the valve springs and collets 2. Use a valve spring tool. Finally fit the rubber seal 1 (MD6A) on the intake valves. 34. Replacing the 0-ring which seals between sleeve and cylinder head.
  • Page 20 Pressure-testing the injectors Overhauling the feed pump 39. Exert force on the pump lever (see Fig.). If the 37. Check the spray pattern at an opening pressure pump “squeaks” then it is in good condition. If it of 180 kp/cm (2560 Ibf/in ).
  • Page 21 41. Unscrew the six bolts holding the upper and 43. Undo the screw 1, and pull out the manual pump lower sections of the pump body together. lever 2 and replace the spring 3 if in poor condi- Remove the pump lever spring 1, and unscrew tion.
  • Page 22 Overhauling the sea-water pump 47. Remove the sealing rings 2 and the 0-ring 1 (earlier engines), and clean the pump body and shaft. (IMPORTANT! The pump must be 45. Remove the cover (6 bolts). Replace the impeller with the help of two screwdrivers or similar tools. removed from the engine.) Check to make sure IMPORTANT! Protect the edges on the pump there is no burr on the shaft.
  • Page 23 Checking the thermostat 51. Oil and fit the bearing halves in the caps. Place the caps according to the marking on the block. Fit the remaining axial bearing halves on the 49. Lower the thermostat into hot water and with a thermometer test to see whether the thermostat intermediate cap with the oil grooves facing opens and closes at the right temperature.
  • Page 24 53. Fit the “protective cover” for the starting crank. 55. Fit a new gasket and install the timing gear Replace the sealing ring and gasket. casing (4 bolts). Tap carefully so as not to deform the guide pins. 54. Fit the camshaft. Observe due care so that the 56.
  • Page 25 57. Fit the intermediate gear. Check that the 59. Install the fuel injection pump. Use a new punched-in figures on the crankshaft drive and gasket. Fit the key on the pump shaft and install camshaft gear wheel coincide with the marking the gear wheel.
  • Page 26 61. Place a new gasket on the inner timing gear 63. Place a new gasket on the water pump and fit it cover and fit the outer timing gear casing. Two with the two bolts. Make sure that the groove in short bolts are fitted at the bottom.
  • Page 27 65. Install the fuel pump. Make sure that the 0-ring 67. Fit the oil sump together with a new gasket. The is in position. Use a new 0-ring. The pump is gasket can only be fitted in one way. Begin with installed with two inhex bolts and spring the four corner bolts for locating the sump into washers.
  • Page 28 69. Fit the key for the flywheel and push on the fly- 71. MD6A. Install the stars generator with its wheel. Fit the thick washer and tighten up the bracket. Screw tight the tensioning bar to the flywheel with the nut. Tightening torque = 180 engine.
  • Page 29 73. Fit the injectors and the overflow pipe. 75a. Adjusting the CAV fuel injection pump Tightening torque for injectors’ nuts 1 = 8 Nm Rotate the flywheel in a clockwise direction until (0,8 kpm = 5,8 lbftf). NOTE! Do not forget the both the valves on No.
  • Page 30 77. Oil the rocker arm and fit the rocker arm cover 79. Fit the key in the crankshaft. Heat the flange and together with new gaskets. Fit the intake fit it on the shaft. Tighten it up with the bolt and manifold and gasket and install the air cleaner.

  • Page 31: Electrical System

    Fig. 82 Wiring diagram for the MD6A with start-generator (no rev counter and temp. gauge) Cable Marking 1. Starter button Des.
  • Page 32 Fig. 83. Wiring diagram for late prod. Type MD6A 1. Key switch 2. Instrument panel switch 3. Temperature gauge 4. Warning light for “low oil pressure” 5. Rev counter 6. Warning light, charging start-generator 7. Switch, optional equipment 8. Terminal board 9.
  • Page 33 Wiring Diagram MD7A CABLE MARKING Des. Colour White Black B’ Black B” Black 0.75 C’ C” Yellow Brown Blue H’ Blue I’ Green/red 0.75 Green J’ Green J” Green 0.75 Blue/yellow 0.75 White/red 0.75 Blue/red 0.75 Position List 2. Charging warning light 3.

  • Page 34: Bleeding The Fuel System

    FAULT TRACING Bleeding the fuel system To ensure that the engine starts, the fuel system must The fault-tracing scheme below includes only those be bled on the following occasions: 1) When changing faults which arise most often during operation. the fine filter. 2) When draining through the drain plug. 3) When cleaning the pre-filter.

  • Page 35: Special Tools

    Special Tools Part No. Description 884537 884538 884549 884539 884541 884535 884543...

  • Page 36: Technical Data

    Technical Data Technical Data MD6A General Type designation MD6A Output (DIN) at 40 rev/sec (2400 rev/mm) 7.4 kW (10 h.p.) Number of cylinders Bore 70 mm (2.7560”) Stroke 82 mm (3.2283”) Capacity 0.63 dm Compression ratio 18.7:1 Compression pressure at starter motor speed 23—25 kp/cm...
  • Page 37 Main bearing journals Diameter, standard 49.984—50.000 mm (1.9679—1.9685”) 0.300 mm undersize 49.684—49.700 mm (1.9560—1.9567”) 0.600 mm undersize 49.384—49.400 mm (1.9442—1.9449”) Main bearing shells Thickness, standard 1.730—1.737 mm (0.0681—0.0684”) 0.300 mm oversize 2.030—2.037 mm (0.0800—0.0802”) 0.600 mm oversize 2.330—2.337 mm (0.0917—0.0920”) Connecting rod journals Diameter, standard 49.984—50.000 mm (1.9679—1.9685”)
  • Page 38 Valve springs Length, off-load 47 mm (1 .8504”) Loaded with 150 N (15 kp = 33 Ibf.) 30 mm (1.1811”) Loaded with 230 N (23 kp = 50 lbf.) 21 mm (0.8268”) Lubricating system Engine Oil capacity excl. filter 2.8 litres (2.5 Imp.qts. = 2.9 US qts.) Oil capacity incl.
  • Page 39 Electrical system Battery voltage 12 V Battery capacity Max. 60 Ah Start-generator Bosch 0 010 350 004 Generator output, max 135W Generator output, continuous 90 W Starter motor output 0.74 kW (1 h.p.) Battery electrolyte specific gravity: Fully charged batter 1.275—1.285 g/cm When charging has to be carried out 1.230 g/cm...
  • Page 40 Technical Data MD7A General MD7A Type designation Output at flywheel (DIN) at 43 rev/sec. (2600 rev/mm.) 10 kW (13.4 h.p.) Number of cylinders Bore 76 mm (2.9921”) Stroke 82 mm (3.2283”) Capacity 0.744 dm Compression ratio 17:1 Compression pressure at starter motor speed 2-2.5 MPa (20—25 kp/cm ) (284—355 lbf/in Direction of rotation, viewed towards flywheel...
  • Page 41 Main bearing journals Diameter, standard 49.984—50.000 mm (1 .9679—1.9685”) 0.300 mm (0.0120”) undersize 49.684—49.700 mm (1.9560—1.9567”) 0.600 mm (0.0236’) undersize 49.384—49.400 mm (1.9442—1.9449”) Main bearing shells Thickness, standard 1.730—1.737 mm (0.0681—0.0684) 0.300 mm (0.0120”) oversize 1.880—1 .887 mm (0.0740—0.0743”) 0.600 mm (0.0236”) oversize 2.030—2.037 mm (0.0799—0.0802”) Big-end journals...
  • Page 42 Valve springs Length, off-load 42.5 mm (1.6732”) Loaded with 170±10 N (17±1 kp = 37.5±2 lbf) 32 mm (1.2598”) Loaded with 300±20 N (30±2 kp = 66±4.5 lbf) 24 mm (0.9449”) Lubricating system Engine Oil capacity, excl. filter 2.8 litres (2.5 lmp.qts. = 2.9 US qts.) Oil capacity, incl.
  • Page 43 Electrical system Battery voltage 12 V Battery capacity Max. 120 Ah Starter motor, Bosch 0 001 311 115 Starter motor output 1.1 kW (1.48 h.p.) Alternator SEV Marchal 70 229712 Alternator output 490W 35A Battery electrolyte specific gravity: Fully charged battery.. 1.275—1.285 g/cm When charging has to be carried out 1.230 g/cm...

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