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Volvo Penta AD31L, Workshop Manual

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Volvo Penta AD31L Workshop Manual Download Page 31

 

30 

Electrical system 

  

 

 

ELECTRICAL SYSTEM 

 

IMPORTANT 

 
82.  The following applies to engines fitted with 

alternators: 

1. 

Never break the current between the 
alternator and battery while the engine is 
running. If a main switch is fitted, it must not 
be switched off until the engine has stopped. 

Otherwise no cable must be disconnected while 
the engine is running, since this also can ruin 
the charging regulator. 

2.  Check regularly the battery, battery cables and 

cable terminals. The battery poles should be 
well-cleaned and the cable terminals always 
well-tightened and well-greased to ensure 
continuous function. All cables in general must 
be well-tightened, there must be no loose 
connections. Note! On no account must the 
battery’s positive and negative poles be mixed 
up when the battery is fitted. 

 
 
 
3.  When starting with the help of a helper battery, 

first check that the helper battery has the same 
rated current as the standard one. Connect the 
helper battery to the standard battery, positive to 
positive and negative to negative. Remove the 
helper battery when the engine has started. 
Note! The cables to the standard battery must 
not be broken. 

4.  With electrical welding on the engine or instal-

lation components, the charging regulator cables 
must first be disconnected and insulated. Both 
the battery cables must also be disconnected. 

5.  In the event of repairs to the alternator 

equipment, both battery cables must first be 
disconnected. The same applies if the battery 
has to be rapidly charged. 

6.  Never test any of the components with a 

screwdriver, etc. against a terminal to see if it 
sparks. 

 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Fig. 82 Wiring diagram for the MD6A with start-generator (no rev counter and temp. gauge) 

Cable Marking 

1. Starter button 

Des. Colour  mm

2

 

AWT 

2. Key switch 

A” 

Beige 

2.5 

13 

3. Charging warning light 

B Bl 

Black 

1.5 

15 

4. Control light for oil pressure 

C Red  25 

3 5. 

Switch 

C 

Red 

2.5 

13 

6. Terminal board, instrument panel resp. engines 

D 

Green 

1.5 

15 

7. Charging regulator 

D Green  2.5 

13 8. 

Start-generator 

G 

Brown 

1.5 

15 

9. Oil pressure indicator 

H 

Blue 

1.5 

15 

10. Battery 12V, max. 60 Ah 

H 

Blue 

25 

3 

11. Main Switch 

 

Summary of Contents for AD31L

Page 1: ...Workshop Manual A Engine unit 2 0 MD6A MD7A AB Volvo Penta Customer Support Dept 42200 SE 405 08 Gothenburg Sweden ...

Page 2: ...Manual Marine diesel engines MD6A MD7A Contents Safety Precautions 2 General information 5 Repair methods 6 Presentation MD6A 8 MD7A 9 Repair instructions 10 Electrical system 30 Special Tools 34 Technical Data 35 ...

Page 3: ... Take precautions to avoid hot surfaces exhausts turbochargers charge air pipes and starter elements etc and liquids in supply lines and hoses when the engine is running or has been turned off immediately prior to starting work on it Reinstall all protective parts removed during service operations before starting the engine Check that the warning information decals on the product are always clearl...

Page 4: ...n from batteries are easily inflammable and explosive Smoking is prohibited Ensure that ventilation is good and that the necessary safety precautions have been taken before carrying out welding or grinding work Always have a fire extinguisher to hand in the workplace Store oil and fuel soaked rags and fuel and oil filters safely In certain conditions oil soaked rags can spontaneously ignite Used f...

Page 5: ...lifting equipment such as secured blocks are being used Even where lifting equipment is being used it is best to carry out the work with two people one to operate the lifting equipment and the other to ensure that components are not trapped and damaged when being lifted When working on board ensure that there is sufficient space to remove components without danger of injury or damage Components in...

Page 6: ...Replacement parts for electrical and fuel systems are subject to statutory requirements US Coast Guard Safety Regulations for example Volvo Penta Genu ine parts meet these requirements Any type of dam age which results from the use of non original Volvo Penta replacement parts for the product will not be covered under any warranty provided by Volvo Penta Certified engines The manufacturer guarante...

Page 7: ...e malfunction or a shorter operational life Our joint responsibility Each engine consists of many connected systems and components If a component deviates from its technical specification the environmental impact of an otherwise good engine may be increased significantly It is therefore vital that wear tolerances are maintained that systems that can be adjusted are adjusted properly and that Volvo...

Page 8: ...siz es in the engines To ensure service work is correctly carried out it is important that the correct sealant and locking fluid type is used on the joint where the agents are re quired In this Volvo Penta Service Manual the user will find that each section where these agents are applied in production states which type was used on the engine During service operations use the same agent or an alter...

Page 9: ...erse gear 9 Oil filling reverse gear 10 Oil pressure contact 11 Lubricating oil filter 12 Start generator 13 Fuel filter 14 Water cooled exhaust manifold 15 Decompression handle 16 Injectors 17 Temperature sender 18 Cooling water outlet 19 Thermostat housing 20 Throttle lever 21 Stop lever 22 Fuel injection pump 23 Oil dipstick engine 24 Fuel return line connection 25 Sea water pump 26 Oil dipstic...

Page 10: ...8 Injector 9 Thermostat housing 10 Oil filling engine 11 Hand start 12 Cooling water drain engine 13 Fuel injection pump 14 Oil dip stick engine 15 Cooling water drain reverse gear 16 Air cleaner and intake silencer 17 Sender rev counter 18 Fuel pump with hand pump 19 Cooling water inlet reduction gear 20 Oil drain reverse gear reduction gear 21 Warner low oil pressure 22 Oil filter ...

Page 11: ... belts Then remove the sea water pump the oil filter the fuel filter and the feed pump Look out for fuel and oil splash 2 Remove the injectors and pipes as well as the leak off oil pipe Discard the sealing washers on both sides of the leak off oil pipe 3 Remove the thermostat housing 2 bolts and the hose clamp under the housing Take the thermostat out of the exhaust manifold Note the small O ring ...

Page 12: ...ther three and are placed towards the centre of the engine Take care of the control bracket Discard the old gasket 7 a BOSCH pump Disconnect the pipe from the fuel filter and remove the nuts for the fuel injection pump 7 b CAV pump Disconnect the pipe from the fuel filter and remove the nuts for the fuel injection pump 8 Remove the nut which drives the water pump Use the flywheel as a counterhold ...

Page 13: ...gear casing from its guide pins Discard the gasket 10 Remove the flywheel Remove the nut and use a puller The axle is tapered and provided with a key Use a counterhold when releasing the nut 11 Knock out the hand starter pin in the camshaft Remove the protective cover 2 bolts NOTE Scrap the sealing ring and fit a new one 12 Remove the front cover behind the flywheel 11 bolts Note the guide pins Ca...

Page 14: ...elease the bolt securing the reverse gear flange to the crankshaft Use a counterhold NOTE Take care of the key Lever loose the rubber damper with a screwdriver 15 Remove the bolt for the intermediate gear Dis card the sealing washer 1 under the bolt Pull off the intermediate gear 16 Check that the shaft pin 1 for the intermediate gear is secure ...

Page 15: ...gine and remove the oil strainer 2 bolts and 1 nut 20 Unscrew the bolts and remove the caps Then carefully tap out the pistons and connecting rods Place connection rods and caps in the same pai ring as when removed to prevent them getting mixed up if they are not marked NOTE Also mark the piston and connecting rod for the re spective cylinders see point 21 On earlier engi nes there is no marking o...

Page 16: ...are punched into the block Replace the axial bearings 1 Check that the guide 2 for the caps is in good condition Lift out the crankshaft 23 Remove the centre nut and washer for the gear wheel on the lubricating oil pump The shaft is ta pered and the gear wheel sits on a key 24 Remove the bolts 4 from the pump body cover and lift off the cover Clean the body and check that the gears are in good con...

Page 17: ...p the bolt 27 Check for wear on pistons piston rings and gud geon pins Replace if necessary The piston and connecting rod must be matchfitted as shown in fig A Make absolutely certain that the groove ring for the gudgeon pin is fitted in its groove The piston rings are fitted with a piston ring rod Begin with the oil ring 1 fig B in the lowest groove Continue with the compression ring 2 Finally fi...

Page 18: ... Remove all the collets 1 Remove the valves IMPORTANT Place the valves in the or der in which they are removed Discard burnt valves if the wear is excessive and grind valve seats if necessary See under Technical Data Seats and valves must be ground together so that the contact surfaces will be absolutely tight 31 Replacing the valve guides With excessive clearance between the valve stem and valve ...

Page 19: ...t against the seat under light pressure If the blue is not distributed evenly on the entire bevel surface of the seat this indicates a leaky valve grind the valve further and re check until results are successful The width of the seat should be approx 1 mm 0 04 Oil the valve stems before filling them in their re spective guides IMPORTANT Make sure that the valves and valve springs are re filled in...

Page 20: ...tervals of 0 05 mm 0 002 between each washer Screw apart the injector and replace the adjuster washer with a thinner or thicker one depending on whether the pressure has to be reduced or in creased Screw the injector together again and check the opening pressure and spray pattern Continue this procedure until results are satisfac tory Overhauling the feed pump 39 Exert force on the pump lever see ...

Page 21: ...an eye on the rubber seal which is pressed into the body 44 Thoroughly clean the pump body and replace worn parts Re fit the manual pump lever Press the di aphragm in and fit the pump lever onto the di aphragm shaft Then insert the shaft and tighten it with the screw IMPORTANT Do not forget the washer on the screw Place the strainer on the upper body section and screw tight the cover and gasket As...

Page 22: ...g 1 earlier engines and clean the pump body and shaft IMPORTANT The pump must be removed from the engine Check to make sure there is no burr on the shaft NOTE A new 0 ring must not be fitted 48 Fit new sealing rings IMPORTANT Turn the sealing rings so that they are in their proper position and make sure that they do not block the drain hole in the pump body Grease the shaft and carefully fit it in...

Page 23: ... each side of the intermediate main bearing with the oil grooves 2 facing outwards 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 intermediate cap with the oil grooves facing outwards NOTE Fit a new 0 ring on the rear cap which is integrally built with the lubricating oil pump The tightening torque fo...

Page 24: ...se a tube or similar as a counterhold 55 Fit a new gasket and install the timing gear casing 4 bolts Tap carefully so as not to deform the guide pins 56 Fit the key in the camshaft and then the gear wheel Turn the gear wheel so that the figure which is punched on the ring gear faces outwards Fit the star washer and the nut on the camshaft Tighten up later on see Point 59 When a new engine block is...

Page 25: ...The figure must face towards the figure on the intermediate gear Tighten up the gear wheel with the nut which also functions as a flange for the water pump Tightening torque 60 Nm 6 kpm 43 Ibftf Use a counterhold Tighten the camshaft nut Remove the counter hold 60 Fit the cylinder head gasket It can only be fitted in one way If the stud bolts in the cylinder head must be replaced fit the new ones ...

Page 26: ...d cover where the water pump is to be installed NOTE The control bracket is fitted with one of the bolts Two bolts are shorter 63 Place a new gasket on the water pump and fit it with the two bolts Make sure that the groove in the pump shaft engages in the flange nut 64 Fit the cover with new gasket over the camshaft end NOTE The bolts have three different lengths The Fig below shows where they are...

Page 27: ...t can only be fitted in one way Begin with the four corner bolts for locating the sump into position Tighten all the bolts thoroughly Remove the sealing ring on the casing for the crankshaft flywheel side Fit a new sealing ring Trim off any part of the oil sump gasket that is sticking out Place a new gasket on the cover and fit it Carefully knock on the cover until it fits over the guide pins Tigh...

Page 28: ...uches the engine Then screw tight a further half turn IMPORTANT Screw by hand 71 MD6A Install the stars generator with its bracket Screw tight the tensioning bar to the engine Earlier engines have a washer placed between the engine and bracket MD7A Install the alternator with its bracket Screw tight the tensioning bar to the engine 72 Install the exhaust manifold Fit a new gasket Check to make sur...

Page 29: ...etting by turning over the engine 1 4 turn in the opposite direction of rotation then back again to the 10 marking on the flywheel Check that the marking 1 and the pointer 2 still coincide e Fit the inspection cover with the rubber gasket 75a Adjusting the CAV fuel injection pump a Rotate the flywheel in a clockwise direction until both the valves on No 1 cylinder are closed compression stroke b A...

Page 30: ... tensioned when they can be depressed under normal thumb pressure about 3 4 mm 1 8 Depress between the start generator and flywheel 79 Fit the key in the crankshaft Heat the flange and fit it on the shaft Tighten it up with the bolt and the thick washer Tightening torque 80 Nm 8 kpm 57 lbftf Bend down the thin washer over the bolt head Fit the rubber damper 80 Install the reverse gear and gasket a...

Page 31: ...r battery to the standard battery positive to positive and negative to negative Remove the helper battery when the engine has started Note The cables to the standard battery must not be broken 4 With electrical welding on the engine or instal lation components the charging regulator cables must first be disconnected and insulated Both the battery cables must also be disconnected 5 In the event of ...

Page 32: ...ev counter 6 Warning light charging start generator 7 Switch optional equipment 8 Terminal board 9 Warning light charging alternator Optional Equipment 10 Battery 11 Main switch 12 Start generator 13 Alternator Optional Equipment 14 Charging regulator 15 Fuse 16 Temperature sender 17 Rev counter 18 Oil pressure sender 19 Other electrical equipment ...

Page 33: ...18 J Green 1 5 15 J Green 0 6 18 J Green 0 75 18 K Blue yellow 0 75 18 L White red 0 75 18 M Blue red 0 75 18 Position List 2 Charging warning light 3 Warning light for high temperature 4 Warning light for low oil pressure 5 Key switch 12 Alternator 6 Siren 13 Fuse 7 Alarm unit 14 Main switch 9 Place for instrument extra equipment 15 Battery 10 Terminal board 16 Temperature sender 11 Starter motor...

Page 34: ...nd when working on the fuel line 7 When the engine has been stopped for a long time Bleeding is as follows Open the bleeder screw 1 on the fine filter See Point 68 Pump forward the fuel with the help of a hand primer until about 0 2 litre 0 2 qt fuel has run out Close the bleeder screw If you get poor pumping effect turn over the engine a bit so that the pump drive cam alters its position If the f...

Page 35: ...34 Special Tools Part No Description 884537 884538 884549 884539 884541 884535 884543 ...

Page 36: ...ring Lower compression ring Oil scraper ring Piston ring gap in cylinder Upper compression ring Lower compression ring Oil scraper ring Crankshaft Material Crankshaft axial clearance Main bearing radial clearance Connecting rod radial clearance 1 Measured with Moto Meter nipple 884535 and yoke 884543 MD6A 7 4 kW 10 h p 2 70 mm 2 7560 82 mm 3 2283 0 63dm 3 18 7 1 23 25 kp cm 2 327 355 lbf in 2 1 Cl...

Page 37: ...ake valve Length exhaust valve Bore Height above cylinder head spring face Clearance valve stemguide 49 984 50 000 mm 1 9679 1 9685 49 684 49 700 mm 1 9560 1 9567 49 384 49 400 mm 1 9442 1 9449 1 730 1 737 mm 0 0681 0 0684 2 030 2 037 mm 0 0800 0 0802 2 330 2 337 mm 0 0917 0 0920 49 984 50 000 mm 1 9679 1 9685 49 684 49 700 mm 1 9560 1 9567 49 384 49 400 mm 1 9442 1 9449 1 730 1 737 mm 0 0681 0 06...

Page 38: ...l injection pump make Bosch Injectors make Bosch holders Nozzles Hole diameter Opening pressure Spray angle Advance angle Injection quantity Max speed Fine filter Type Filter insert Feed pump Type Feed pressure at 40 rev see 2400 rev mm 47 mm 1 8504 30 mm 1 1811 21 mm 0 8268 2 8 litres 2 5 Imp qts 2 9 US qts 3 0 litres 2 6 lmp qts 3 2 US qts CD DS SAE 30 SAE 20W 0 8 1 5 kp cm 2 11 4 2 1 3 Ibf in 2...

Page 39: ...rnals permitted out of roundness Max clearance between camshaft and bushings Valves Max clearance between valve stem and guide Edge of valve disc should be mm TIGHTENING TORQUES Cylinder head nuts Cylinder head stud bolts Bolt for flange on crankshaft Flywheel nut Connecting rod bolts Water pump flange Main bearings Nuts for fork for injectors Tightening scheme for cylinder head nuts 12 V Max 60 A...

Page 40: ...pression ring Lower compression ring Oil scraper ring Piston ring gap in cylinder Upper compression ring Lower compression ring Oil scraper ring Crankshaft Material Crankshaft axial clearance Main bearing radial clearance Big end bearings radial clearance MD7A 10 kW 13 4 h p 2 76 mm 2 9921 82 mm 3 2283 0 744 dm 3 17 1 2 2 5 MPa 20 25 kp cm 2 284 355 lbf in 2 Clockwise 11 13 rev sec 650 780 rev min...

Page 41: ... valve Length exhaust valve Bore Height above cylinder head spring face Clearance valve stem guide intake valve exhaust valve 49 984 50 000mm 1 9679 1 9685 49 684 49 700mm 1 9560 1 9567 49 384 49 400mm 1 9442 1 9449 1 730 1 737 mm 0 0681 0 0684 1 880 1 887 mm 0 0740 0 0743 2 030 2 037 mm 0 0799 0 0802 49 984 50 000 mm 1 9679 1 9685 49 684 49 700 mm 1 9560 1 9567 49 384 49 400 mm 1 9442 1 9449 1 73...

Page 42: ...jection pump CAV From engine no 20000 Injectors make Bosch holders Nozzles Hole diameter Opening pressure Spray angle Advance angle Bosch pump Advance angle CAV pump Injection quantity Bosch pump Injection quantity CAV pump Feed pump Type Feed pressure at 42 rev sec 2500 rev mm 42 5 mm 1 6732 32 mm 1 2598 24 mm 0 9449 2 8 litres 2 5 lmp qts 2 9 US qts 3 0 litres 2 6 lmp qts 3 2 US qts CD DS SAE 20...

Page 43: ...nd guide Edge of valve disc should be mm Tightening torques Cylinder head nuts Cylinder head stud bolts Bolt for flange on crankshaft Flywheel nut Connecting rod bolts Water pump flange Bosch fuel injection pump Water pump flange CAV fuel injection pump Main bearings Nuts for fork for injectors Bolt for intermediate gear transmission Starter motor bolt Bolt front engine mounting Bolt rear engine m...

Page 44: ...43 Longitudinal section Cross section ...

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