Volvo Coupes/Sedans/Wagons 1970-1989 Repair Guide

Cylinder Head

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REMOVAL & INSTALLATION



B20B and B30A Engines

See Figures 1, 2 and 3


WARNING
To prevent warpage of the head, removal should be attempted only on a cold engine. All wires and hoses should be labled at the time of removal. The amount of time saved during reassembly makes the extra effort well worthwhile.

  1. Drain the cooling system by opening the drain plug on the right-hand side of the engine and disconnecting the lower radiator hose at the radiator.
  2.  


CAUTION
When draining the coolant, keep in mind that cats and dogs are attracted by ethylene glycol antifreeze, and are quite likely to drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantity. Always drain the coolant into a sealable container. Coolant should be reused unless it is contaminated or several years old.

  1. Disconnect the choke control cables at the carburetors. Remove the positive crankcase ventilation hoses from the air cleaner and intake manifold. Remove the vacuum hoses for the distributor advance and the power brake booster, if so equipped.
  2.  
  3. Remove the throttle control shaft from the pedal shaft, link rods, and bracket. (Disconnect the downshift linkage on cars with automatic transmissions).
  4.  
  5. Remove the air cleaner, inlet hose, and heat control valve hose from the engine.
  6.  
  7. Remove the upper radiator hose. Remove the heater hose clamp from the head.
  8.  
  9. Remove and plug the fuel line at the carburetors.
  10.  
  11. Label the spark plug wires and disconnect them from the plugs. Disconnect the coolant temperature sensor.
  12.  
  13. Remove the exhaust manifold preheating plate. Remove the nuts and disconnect the exhaust pipe from the exhaust manifold.
  14.  
  15. Unbolt the alternator adjusting arm from the head.
  16.  
  17. Remove the valve cover. Remove the rocker shaft and arm assembly as a unit and draw out the pushrods, keeping them in order.
  18.  
  19. Loosen the head bolts gradually, in the same order as their tightening sequence. Remove the head bolts, noting their locations, and lift off the head. Do not attempt to pry off the head. The head may be tapped lightly with a rubber mallet to break the gasket seal. If any residual water in the cooling passages of the head falls into the combustion chambers during removal, remove it immediately and coat the cylinder walls with oil.
  20.  
  21. Remove the integrally cast intake and exhaust (combination) manifold from the cylinder head.
  22.  
  23. Remove the old head gasket, flange gasket, and rubber sealing rings for the water pump.
  24.  
  25. Inspect the condition of the valves in the combustion chambers, and the intake and exhaust ports in the head. Small deposits may be removed with rotating brushes. If large deposits are present, however, proceed to Cylinder Head Reconditioning in the Engine Rebuilding portion of this section. Make sure that no foreign matter has fallen into the cylinders or onto the tops of the pistons. Thoroughly clean the mating surfaces of the cylinder head and block, removing any traces of the old head gasket. Check the mating surfaces for warpage. There is an oil feed hole for the rocker arm assembly on the tappet side, in the middle of the head. Make sure it is clean. A clogged oil feed hole may be opened with a length of thin gauge metal wire and some kerosene to dissolve the deposits. Clean the top of the cylinder head and the oil return holes to remove any gum or foreign matter. Clean and oil the head bolts.
  26.  

To install:
  1. Install the combination intake and exhaust manifold on the head with new gaskets.
  2.  



Click image to see an enlarged view

Fig. Fig. 1: Install the (temporary) guide studs to allow the cylinder head to mate properly to the block-Volvo factory guide stud shown

  1. Install new sealing rings for the water pump.
  2.  
  3. Use a pair of guide studs for proper alignment of the cylinder head, head gasket, and block. Guide studs can be easily made by cutting the heads off a pair of spare head bolts. The tops of the bolts are then filed to a tapered edge and slotted so that they may be installed and removed with a screwdriver. The guide studs should be installed in the cylinder block; one in the front right-hand head bolt hole, and the other in the rear left-hand head bolt hole.
  4.  



Click image to see an enlarged view

Fig. Fig. 2: Cylinder head tightening sequence-B20 engine



Click image to see an enlarged view

Fig. Fig. 3: Cylinder head tightening sequence-B30 engine

  1. Fit a new head gasket on the cylinder block with the lettering TOP (wide edge) facing up. Slide the gasket down over the two guide studs.
  2.  
  3. Carefully lower the cylinder head over the guide studs onto the block. Install, but do not tighten, two heads bolts at opposite ends to secure the gasket, and remove the guide studs. Install the remaining head bolts finger-tight. Tighten the head bolts in proper sequence first to 29 ft. lbs. (39 Nm), and then to 58 ft. lbs. (79 Nm).
  4.  
  5. Roll the pushrods on a level surface to inspect them for straightness. Replace any bent pushrods. Install the pushrods in their original positions and install the rocker shaft and arm assembly. Tighten the bolts to approximately 20 ft. lbs. (27 Nm).
  6.  
  7. Adjust the valve clearance to 0.018-0.020 in. (0.45-0.50mm) for the B30A, and 0.022-0.024 in. (0.55-0.60mm) for the B20B. Install the valve cover with a new gasket.
  8.  
  9. Install the alternator adjusting arm and adjust the drive (fan) belt tension.
  10.  
  11. Install the following:
    1. Exhaust manifold preheating plate
    2.  
    3. Exhaust pipe and flange nuts (with new gaskets)
    4.  
    5. Spark plugs wires
    6.  
    7. Coolant temperature sensor
    8.  
    9. Heater hose clamp
    10.  
    11. Upper and lower radiator hoses
    12.  
    13. Fuel line
    14.  
    15. Air cleaner
    16.  
    17. Inlet hose
    18.  
    19. Heat control valve hose
    20.  
    21. Choke and throttle linkage (down shift linkage on cars with automatic transmissions)
    22.  
    23. Vacuum hoses for the distributor and power brake (if so equipped)
    24.  
    25. The positive crankcase ventilation hose
    26.  

  12.  
  13. Close the drain plug and fill the cooling system with a 50 percent antifreeze, 50 percent water solution.
  14.  
  15. Run the engine until it reaches operating temperature, then stop the engine
  16.  
  17. Remove the valve cover and tighten the head bolts in proper sequence to the final figure of 65 ft. lbs. (88 Nm).
  18.  
  19. Adjust the valve clearance to the final setting of 0.020-0.022 in. (0.50-0.55mm).
  20.  
  21. Install the valve cover.
  22.  

B20E, 1972-73 B20F and B30F Engines

See Figures 1, 2 and 3

The procedure for removal and installation of the cylinder head for the fuel injected engines differs from the carbureted engines only in the type of fuel system equipment that must be moved to gain access to the head.


WARNING
To prevent warpage of the head, removal should only be attempted on a cold engine. All wires and hoses should be labled at the time of removal. The amount of time saved during reassembly makes the extra effort well worthwhile.

  1. Drain the cooling system by opening the drain plug on the right-hand side of the engine and disconnecting the lower radiator hose at the radiator.
  2.  


CAUTION
When draining the coolant, keep in mind that cats and dogs are attracted by ethylene glycol antifreeze, and are quite likely to drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantity. Always drain the coolant into a sealable container. Coolant should be reused unless it is contaminated or several years old.

  1. Disconnect the negative battery cable from the engine.
  2.  
  3. On the B30F engine, remove the air cleaner.
  4.  
  5. Remove the following hoses from the inlet duct: pressure sensor, power brake (if so equipped), distributor advance, and crankcase ventilation (PCV).
  6.  
  7. Remove the electrical contacts for the throttle valve switch, cold start valve, thermal timer, temperature sensor, and injectors.
  8.  
  9. Remove the ground cable from the inlet duct and remove the cable harness.
  10.  
  11. Disconnect the sensor for the coolant temperature gauge. Remove the spark plug wires from the plugs.
  12.  
  13. On the B20E and B20F engines, remove the inlet hose.
  14.  
  15. Disconnect the throttle control cable from the throttle valve and inlet duct.
  16.  
  17. Remove the upper radiator hose.
  18.  
  19. Remove the heater control valve hose and the clamp for the heater pipe.
  20.  
  21. Unbolt the alternator adjusting arm from the head.
  22.  
  23. Remove the bolts for the inlet duct (intake manifold) stay. Remove the inlet duct-to-cylinder head retaining nuts and disconnect the inlet duct.
  24.  
  25. If any cleaning or machine work is to be performed on the cylinder head, remove the fuel injectors beforehand. Turn the lockrings on the injectors counterclockwise and lift out the injectors and distributing pipe as a unit. Remove the injector holders from the head.
  26.  


CAUTION
The fuel system is under pressure. Release pressure slowly and contain spillage. Observe no smoking/no open flame precautions

  1. Remove the exhaust manifold-to-exhaust pipe flange nuts and disconnect the pipe.
  2.  
  3. Remove the valve cover. Remove the rocker shaft and arm assembly as a unit and draw out the pushrods, keeping them in order.
  4.  
  5. Loosen the head bolts gradually, in the same order as their tightening sequence. Remove the head bolts, noting their locations, and lift off the head. Do not attempt to pry off the head. The head may be tapped lightly with a rubber mallet to break the gasket seal. If any residual water in the cooling passages of the head falls into the combustion chambers during removal, remove it immediately and coat the cylinder walls with oil.
  6.  
  7. Remove the exhaust manifold from the head.
  8.  
  9. Remove the old head gasket, flange gasket, and rubber sealing rings for the water pump.
  10.  
  11. Inspect the condition of the valves in the combustion chambers, and the intake and exhaust ports in the head. Small deposits may be removed with rotating brushes. If large deposits are present, however, proceed to Cylinder Head Reconditioning in the Engine Rebuilding portion of this section. Make sure that no foreign matter has fallen into the cylinders or onto the tops of the pistons. Thoroughly clean the mating surfaces of the cylinder head and block, removing any traces of the old head gasket. Check the mating surfaces for warpage. There is an oil feed hole for the rocker arm assembly on the tappet side, in the middle of the head. Make sure it is clean. A clogged oil feed hole may be opened with a length of thin gauge metal wire and some kerosene to dissolve the deposits. Clean the top of the cylinder head and the oil return holes to remove any gum or foreign matter. Clean and oil the head bolts.
  12.  

To install:
  1. Install the exhaust manifold on the head with a new gasket.
  2.  
  3. Install new sealing rings for the water pump.
  4.  
  5. Use a pair of guide studs for proper alignment of the cylinder head, head gasket, and block. Guide studs can be easily made by cutting the heads off a pair of spare head bolts. The tops of the bolts are then filed to a tapered edge and slotted so that they may be installed and removed with a screwdriver. The guide studs should be installed in the cylinder block; one in the front right-hand head bolt hole, and the other in the rear left-hand head bolt hole.
  6.  
  7. Fit a new head gasket on the cylinder block with the lettering TOP (wide edge) facing up. Slide the gasket down over the two guide studs.
  8.  
  9. Carefully lower the cylinder head over the guide studs onto the block. Install, but do not tighten, two heads bolts at opposite ends to secure the gasket, and remove the guide studs. Install the remaining head bolts finger-tight. Tighten the head bolts in proper sequence first to 29 ft. lbs. (39 Nm), and then to 58 ft. lbs. (79 Nm).
  10.  
  11. Roll the pushrods on a level surface to inspect them for straightness. Replace any bent pushrods. Install the pushrods in their original positions and install the rocker shaft and arm assembly. Tighten the bolts to approximately 20 ft. lbs. (27 Nm).
  12.  
  13. Adjust the valve clearance to 0.018-0.020 in. (0.45-0.50mm) for the B20E and B20F, and 0.022-0.024 in. (0.55-0.60mm) for the B30F. Install the valve cover with a new gasket.
  14.  
  15. If the injectors were removed, install the holders with new sealing rings. Install the injectors and distributing pipe as a unit.
  16.  
  17. Install the alternator adjusting arm and adjust the drive (fan) belt tensioner.
  18.  
  19. Install the inlet duct with a new gasket. Install the inlet duct retaining nuts and the bolts for the inlet duct stay. On B20 engines, install the inlet hose.
  20.  
  21. Install the following:
    1. Upper and lower radiator hoses
    2.  
    3. Heater hose
    4.  
    5. Exhaust pipe flange nuts
    6.  
    7. Fuel line
    8.  
    9. Throttle linkage
    10.  
    11. Temperature gauge sensor
    12.  
    13. Ground cable to inlet duct
    14.  
    15. Cable harness
    16.  
    17. Electrical contacts for the throttle valve switch
    18.  
    19. Cold start valve
    20.  
    21. Thermal timer
    22.  
    23. Temperature sensor and injectors
    24.  
    25. Pressure sensor hose
    26.  
    27. Power brake hose
    28.  
    29. Distributor advance line
    30.  
    31. Crankcase ventilation hoses, and the battery cables.
    32.  

  22.  
  23. On the B30F engine, install the air cleaner.
  24.  
  25. Close the drain plug and fill the cooling system with a 50 percent antifreeze, 50 percent water solution.
  26.  
  27. Start the engine and run it until it reaches normal operating temperature, then shut it off.
  28.  
  29. Remove the valve cover and tighten the head bolts in proper sequence to the final figure of 65 ft. lbs. (88 Nm).
  30.  
  31. Adjust the valve clearance to the final setting of 0.016-0.018 in. (0.40-0.45mm) for the B20E and B20F, and 0.020-0.022 in. (0.50-0.55mm) for the B30F.
  32.  

1974-75 B20F Engine

WARNING
To prevent head warpage, removal should be performed only on a cold engine. All wires and hoses should be labled at the time of removal. The amount of time saved during reassembly makes the extra effort well worthwhile.

  1. Drain the cooling system by removing the plug on the right side of the engine and disconnecting the lower radiator hose.
  2.  


CAUTION
When draining the coolant, keep in mind that cats and dogs are attracted by ethylene glycol antifreeze, and are quite likely to drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantity. Always drain the coolant into a sealable container. Coolant should be reused unless it is contaminated or several years old.

  1. Remove the negative lead from the battery.
  2.  
  3. Disconnect hoses to brake vacuum booster and crankcase ventilation.
  4.  
  5. Remove the cold start injector hose and the fuel return hoses on both sides of the T-connection (at the control pressure regulator).
  6.  
  7. Remove the outlet fuel hose at the fuel filter and remove fuel filter with its clamp from the firewall.
  8.  
  9. Disconnect the fuel hose from the fuel distributor at the control pressure regulator.
  10.  
  11. Disconnect electrical wires at cold start injector, auxiliary air valve, control pressure regulator and temperature sensor.
  12.  
  13. Remove the air cleaner connecting pipe.
  14.  
  15. Disconnect the throttle cable at the intake manifold.
  16.  
  17. Disconnect the hose for heater and the upper radiator hose.
  18.  
  19. Remove the alternator adjustment bracket.
  20.  
  21. Remove the straps from the injector hoses. Remove the injectors and hoses from the cylinder head, by turning the lockrings counterclockwise.
  22.  
  23. Remove the bracket for the intake manifold, and remove the manifold.
  24.  
  25. Remove the exhaust manifold from exhaust pipe and cylinder head.
  26.  
  27. Remove the spark plugs and spark plug wires.
  28.  
  29. Remove the valve cover, rocker arm shaft and the pushrods.
  30.  
  31. Remove the cylinder head bolts and lift off the head. Take off the cylinder head gasket, the flange gasket and the rubber rings for the water pump.
  32.  
  33. Follow Steps 14, 16, 17, 18, 19 and 20 under Cylinder Head Removal and Installation for the B20B.
  34.  
  35. Install pushrods and rocker arm shaft. Adjust the valves to 0.018-0.020 in. (0.45-0.50mm).
  36.  
  37. Continue reassembly in the opposite order of disassembly. Tighten the manifold nuts to 18 ft. lbs. 24 Nm). Use care in refitting the fuel injection lines and maintain their cleanliness. When all hoses are attached and secure, refill the cooling system with a 50-50 mixture of antifreeze and water.
  38.  
  39. Double check all installation items, paying particular attention to loose hoses or hanging wires, loose nuts, poor routing of hoses and wires (too tight or rubbing) and tools left in the engine area.
  40.  
  41. Start the engine and allow it to reach normal operating temperature. Remove the valve cover and tighten the head bolts--in the correct order--to 65 ft. lbs. (88 Nm). Adjust the valves to their final setting of 0.016-0.018 in. (0.40-0.45mm). Replace the valve cover.
  42.  

B21 and B23 Series Engines

See Figures 4, 5, 6, 7, 8, 9 and 10

  1. Disconnect the negative battery cable.
  2.  
  3. Remove the overflow tank cap and drain the coolant. Disconnect the upper radiator hose.
  4.  


CAUTION
When draining the coolant, keep in mind that cats and dogs are attracted by ethylene glycol antifreeze, and are quite likely to drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantity. Always drain the coolant into a sealable container. Coolant may be reused unless it is contaminated or several years old.

  1. Remove the distributor cap and wires.
  2.  
  3. Remove the PCV hoses.
  4.  
  5. Remove the EGR valve and vacuum pump.
  6.  
  7. Remove the air pump, and air injection manifold. Plug all open hoses, lines and ports.
  8.  
  9. Remove the exhaust manifold and header pipe bracket.
  10.  
  11. Remove the intake manifold. Disconnect the manifold brace and the hose clamp to the bellows for the fuel injection air/flow unit. Disconnect the throttle cable.
  12.  
  13. Disengage all vacuum hoses and electrical connectors to the fuel injection unit.
  14.  

All wires and hoses should be labled at the time of removal. The amount of time saved during reassembly makes the extra effort well worthwhile.

  1. Remove the fuel injectors.
  2.  
  3. Remove the valve cover.
  4.  
  5. Loosen the fan shroud and remove the fan. Remove the shroud. Remove the upper belts and pulleys.
  6.  
  7. Remove the timing belt cover. Remove the timing belt as described later in this section.
  8.  
  9. Remove the camshaft (if so desired) as outlined later in this section.
  10.  
  11. Remove the cylinder head (10mm Allen head bolts). Loosen the bolts in order opposite to the tightening sequence (10-9-8 ... etc.).
  12.  



Click image to see an enlarged view

Fig. Fig. 4: Cylinder head bolt tightening sequence-B21 and B23 engines



Click image to see an enlarged view

Fig. Fig. 5: Use an extension and sufficiently long-handled breaker bar or ratchet to remove the cylinder head bolts



Click image to see an enlarged view

Fig. Fig. 6: Lift away the detached cylinder head from the block and place it in a safe location



Click image to see an enlarged view

Fig. Fig. 7: Remove the old cylinder head gasket and discard it

To install:
  1. Make sure the surface is clean and free of old gasket material. Use a new gasket and lightly oil the head bolts. Carefully place the head on the block and tighten the bolts in the prescribed order to 44 ft. lbs. (60 Nm). When all bolts are at 44 ft. lbs. (60 Nm), repeat the pattern and tighten to 81 ft. lbs. (110 Nm).
  2.  



Click image to see an enlarged view

Fig. Fig. 8: Clean any residual material so the mating surfaces are clean and smooth prior to reinstallation



Click image to see an enlarged view

Fig. Fig. 9: Use a new gasket aligned correctly on the block

  1. If the camshaft was removed, reinstall it.
  2.  
  3. Replace the timing belt. Follow the procedures listed under Timing Belt Installation and Removal later in this section.
  4.  



Click image to see an enlarged view

Fig. Fig. 10: Tighten the cylinder head bolts according to the correct torque figures in the proper sequence

  1. Attach the upper belts and pulleys. Reinstall the fan and shroud.
  2.  
  3. Reinstall the valve cover.
  4.  
  5. Reinstall the fuel injectors.
  6.  
  7. Using new gaskets, attach the intake manifold. Secure its brace and attach the bellows for the air/flow unit. Reconnect the throttle cable.
  8.  
  9. Connect all vacuum lines and the electrical connectors to the fuel injectors.
  10.  
  11. Install the exhaust manifold and header pipe bracket.
  12.  
  13. Remembering to remove all of the plugs, reconnect the lines to the turbocharger if so equipped. If equipped with an air pump, reinstall it along with the air injection manifold.
  14.  
  15. Install the EGR valve and lines and connect the PCV hoses. Replace the distributor cap and wires.
  16.  
  17. Connect the hoses to the radiator. Fill the system with a 50-50 mix of antifreeze and water.
  18.  
  19. Reconnect the battery. Double check all installation items, paying particular attention to loose hoses or hanging wires, loose nuts, poor routing of hoses and wires (too tight or rubbing) and tools left in the engine area.
  20.  
  21. Start the motor and check for leaks. As the engine warms up, observe the coolant level and top off as needed.
  22.  
  23. When the engine has reached normal operating temperature, shut it off and allow it to cool for at least 30 minutes. Carefully remove the valve cover. Be careful; the engine parts will be hot.
  24.  
  25. Observe the correct tightening sequence and loosen each bolt enough to relieve any pre-tension. Tighten each bolt to 81 ft. lbs. (110 Nm) before loosening the next.
  26.  
  27. Perform any needed valve lash adjustments and replace the valve cover.
  28.  

B230F Engine

See Figures 11, 12, 13, 14, 15 and 16

  1. Disconnect the negative battery cable.
  2.  
  3. Drain the coolant from the motor. Open the drain cock on the right side of the engine and connect a short piece of hose to prevent spillage.
  4.  


CAUTION
When draining the coolant, keep in mind that cats and dogs are attracted by ethylene glycol antifreeze, and are quite likely to drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantity. Always drain the coolant into a sealable container. Coolant should be reused unless it is contaminated or several years old.

  1. Remove the valve cover. Remove the retaining nuts for the exhaust manifold. Gently pull the manifold off the studs just enough to allow clearance.
  2.  
  3. Remove the intake manifold. Follow the detailed instructions under Intake Manifold Removal and Installation earlier in this section.
  4.  
  5. Remove the fan, the fan shroud, and the clamp for the pre-heat hose, located under the fan shroud.
  6.  
  7. Remove the drive belts (loosen the adjustors as necessary) and remove the pulley for the water pump.
  8.  
  9. Remove the upper timing gear cover.
  10.  
  11. Remove the spark plugs. Remove the spark plug wires and distributor cap.
  12.  
  13. Use the center bolt of the crankshaft to turn the engine. Slowly rotate the engine until the mark on the camshaft pulley is opposite the mark on the inner timing gear cover. The crankshaft mark should align with the "0" on the lower timing gear cover. If the distributor is located on the side of the engine (not in the cylinder head), check that the rotor is aligned with the mark (notch) in the case of the distributor.
  14.  



Click image to see an enlarged view

Fig. Fig. 11: Align the crankshaft and camshaft marks before removing the timing belt-B230F engines

  1. Remove the nut and washer for the timing belt tensioner. Pull on the timing belt to compress the tensioner spring. Use a 3mm drill bit to lock the tensioner spring. Remove the belt and the tensioner.
  2.  



Click image to see an enlarged view

Fig. Fig. 12: Use a 3mm drill bit (indicated by the arrow) to hold the belt tensioner spring


WARNING
Once the timing belt has been removed, do not allow either the crankshaft or the camshaft to turn while the cylinder head is on the car. The pistons may hit the valves causing severe damage.

  1. Remove the camshaft gear and spacer. Do not allow the cam to turn during removal.
  2.  
  3. Remove the stud bolt for the timing belt tensioner.
  4.  
  5. Consult the head bolt diagram. Loosen the head bolts in REVERSE order to that shown in the diagram. (Begin with 10, then 9, 8, etc.) Remove the cylinder head. The head is made of aluminum alloy; when placing the cylinder head on the workbench, support the cylinder head on wooden blocks so that the gasket face is not scratched or gouged.
  6.  



Click image to see an enlarged view

Fig. Fig. 13: Head bolt tightening sequence for the B230F. When removing, loosen the bolts in the reverse order

To install:
  1. Check the position of the crankshaft. Number 1 piston should be at TDC. Check the position of the camshaft. The lobes for cylinder No. 1 should point at equally large angles. (Both valves are closed.)
  2.  



Click image to see an enlarged view

Fig. Fig. 14: Make sure the camshaft and No. 1 piston are in the correct position before placing the cylinder head on the block

  1. Position the new head gasket and and the cylinder head. Make sure that the O-ring for the water pump is correctly placed in its groove. Remember that from this point, the camshaft and crankshaft must not be rotated or valve and piston damage may result.
  2.  
  3. Inspect the cylinder head bolts. Replace them if the center section shows any sign of stretching or other wear. If there is any doubt, replace them.
  4.  
  5. Apply a light coat of oil to the bolts and install them in the head. Using the sequence shown in the diagram, use a three stage tightening procedure:
  6.  



First stage: Tighten all bolts to 14 ft. lbs. (19 Nm)
 
Second stage: Tighten all bolts to 43 ft. lbs. (58 Nm)
 
Third stage: Tighten all bolts exactly 90°.
 

During final tightening, you may opt to use Volvo tool No. 5098, a protractor used to precisely gauge the degrees rotation of the torque wrench.



Click image to see an enlarged view

Fig. Fig. 15: For final tightening, turn the bolts an additional 90° as shown. Do not exceed the specified degrees

  1. Install the camshaft gear and spacer. Do not allow the cam to turn during installation.
  2.  
  3. Install the stud bolt for the belt tensioner, then install the tensioner with its washer and nut.
  4.  
  5. Double check that all marks on the cam and crank pulleys align as described in Step 9, above.
  6.  
  7. Place the timing belt around the crankshaft gear and intermediate shaft gear. Gently stretch the belt and place it over the camshaft gear and belt tensioner. Don't use sharp or pointed tools to pry on the belt.
  8.  
  9. Remove the drill bit from the tensioner. Double check that the camshaft and crankshaft pulleys are still in their exact, proper positions.
  10.  
  11. Rotate the engine one full rotation until it returns to top dead center and the marks align as before. Loosen the timing belt tensioner nut about one turn; the spring will set the correct tension on the timing belt. Retighten the nut.
  12.  



Click image to see an enlarged view

Fig. Fig. 16: Adjust the timing belt by loosening the tensioner bolt about one full turn and retightening. An internal spring will tension the belt

  1. Adjust the valve lash if not done during head repairs or overhaul.
  2.  
  3. Install the valve cover with a new gasket.
  4.  
  5. Reinstall the intake and exhaust manifolds. Refer to the detailed instructions earlier in this section.
  6.  
  7. Replace the spark plugs, the distributor cap and the spark plug wires.
  8.  
  9. Reinstall the upper timing gear cover. Attach the water pump pulley and the drive belts.
  10.  
  11. Attach the fan and fan shroud. Reconnect the clamp and pre-heater hose. Adjust the drive belts.
  12.  
  13. If not already done, close the drain cock on the side of the engine. Refill the cooling system with a 50-50 mixture of antifreeze and water.
  14.  
  15. Double check all installation items, paying particular attention to loose hoses or hanging wires, loose nuts, poor routing of hoses and wires (too tight or rubbing) and tools left in the engine area.
  16.  
  17. Reconnect the battery cable. Start the engine and check for leaks. After the engine has come to normal operating temperature, check the coolant level and top off as needed.
  18.  
  19. While the head bolts DO NOT need to be retightened, the timing belt should be readjusted after 500-600 miles of driving. Remove the rubber plug in the timing gear cover, rotate the engine (turn the crankshaft pulley nut) to the TDC position on cylinder No. 1, and loosen the belt tensioner nut. The spring will correctly tension the belt; tighten the nut and replace the rubber plug.
  20.  

B234F Engine

See Figures 17, 18 and 19

The use of the correct special tools or their equivalent is REQUIRED for this procedure.

  1. Disconnect the negative battery cable.
  2.  
  3. Remove the heat shield over the exhaust manifold.
  4.  
  5. Remove the cap from the expansion tank and open the draincock on the right side of the motor. Collect the drained coolant in a suitable container.
  6.  


CAUTION
When draining the coolant, keep in mind that cats and dogs are attracted by ethylene glycol antifreeze, and are quite likely to drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantity. Always drain the coolant into a sealable container. Coolant should be reused unless it is contaminated or several years old.

  1. Unbolt the exhaust pipe from the bracket, remove the manifold nuts and remove the manifold from the head.
  2.  
  3. On the left side of the motor, remove the support under the intake manifold. and remove the bottom bolt in the cylinder block.
  4.  
  5. Remove the manifold intact and tie it or support it safely.
  6.  
  7. Disengage the temperature sensor connectors, the heating hose under cylinders 3 and 4 and the upper radiator hose at the thermostat.
  8.  
  9. Remove the upper and lower timing belt covers.
  10.  
  11. Align the camshaft and crankshaft marks. Turn the engine to TDC on cylinder 1 and make sure the pulley marks and the crank marks align.
  12.  
  13. Remove the protective cap over the timing belt tensioner locknut. Loosen the lock nut, compress the tensioner (so as to release tension on the belts) and retighten the locknut, holding the tensioner in place.
  14.  
  15. Remove the timing belt from the camshafts. Do not crease or fold the belt.
  16.  


WARNING
The camshafts and the crankshaft MUST NOT be moved when the belt is removed.

  1. Remove the timing belt idler pulleys.
  2.  
  3. Remove the camshaft drive pulleys. Use a counterhold wrench to prevent the cam from turning.
  4.  
  5. Remove the plate or panel behind the pulleys. Remove the cover plate for the ignition wires. Label and disconnect the ignition wiring from the spark plugs and the distributor cap; remove the coil wire from the distributor cap.
  6.  
  7. Remove the valve cover and gasket. Clean the surfaces of any gasket remains.
  8.  
  9. Remove the distributor housing from the camshaft carrier. Remove the ignition wire clip next to the left bolt.
  10.  
  11. Plug the spark plug holes with crumpled paper. Remove the center bearing cap for each camshaft. Remove the third nut in the center. Mark the cam bearing caps for proper reinstallation.
  12.  
  13. Install a camshaft press tool, such as Volvo 5021 or similar on the exhaust side cam in place of the removed bearing cap. When it is securely in place, remove the remaining bearing caps and nuts. Remove the tool and remove the exhaust camshaft.
  14.  
  15. Remove the intake camshaft in identical fashion.
  16.  

Label or identify each cam and its bearing caps. All removed components must be kept in order.

  1. Using a magnet or a small suction cup, remove the tappets. Store them upside down (to prevent oil drainage) and keep them in order. They are not interchangeable!
  2.  
  3. Remove the remaining four nuts in the center of the cam carrier and detach the carrier from the head. If it is stuck, tap it very gently with a plastic mallet. Remove the O-rings around the spark plug holes.
  4.  
  5. Wipe the remaining oil off the cylinder head and remove the bolts in the order shown. When all the bolts are removed, the cylinder head may be lifted free of the car.
  6.  


WARNING
The head is aluminum. Support it on clean wood blocks or similar to avoid scoring the face.

  1. Clean the camshaft carrier and the head assembly of all gasket material and sealer. Carefully scrape the joint surfaces with a plastic scraper. Do NOT use metal tools to scrape or clean. Wash the surfaces with a degreasing compound and blow the surfaces completely dry. Inspect the head bolts for any sign of stretching or elongation in the midsection. If this is observed or suspected, discard the bolt. Bolts may not be used more than five times.
  2.  
  3. Install the new head gasket and a new O-ring for the water pump. Carefully place the cylinder head into position; do not damage the gasket.
  4.  
  5. Clean the head bolts and apply a light coat of oil. Install them and tighten (in the order shown) in three steps: All to 15 ft. lbs. (20 Nm), then all to 30 ft. lbs. (41 Nm). Third step is to tighten each bolt through 115° of arc in one continuous motion. The use of Volvo tool No. 5098 (protractor fitting) is strongly recommended for this task.
  6.  
  7. Install the exhaust manifold with a new gasket. Attach the front exhaust pipe to its bracket and install the heat shields.
  8.  
  9. On the left side of the motor, connect the temperature sensors, the heating hose under cylinders 3 and 4 and the upper coolant hose to the thermostat.
  10.  
  11. Fill the cooling system and check carefully for leaks, particularly around the head to block joint.
  12.  
  13. Install the intake manifold with a new gasket. Tighten the bottom bolts a few turns and place the manifold in position. Tighten all the bolts from the center outwards.
  14.  
  15. Reattach the support under the intake manifold and the cable clip. Double check all connections on and around the intake manifold.
  16.  
  17. Apply Volvo liquid sealing compound to the camshaft carrier. Use a small paint roller and coat the surfaces which match to the head and the bearing cap joint faces.
  18.  
  19. Install the cam carrier on the head and secure it with four of the five center nuts tightened to 15 ft. lbs. (20 Nm). Do not install the middle nut.
  20.  
  21. Oil all matching surfaces on the cam carrier, bearing caps and tappets.
  22.  
  23. Insert the tappets; they MUST be inserted in their original order and place.
  24.  
  25. Install the exhaust side camshaft by placing it in the carrier with the pulley guide pin facing up. Using the rear bearing cap as a guide, press the cam into place with the press tool. Install the bearing caps in the original order.
  26.  
  27. Install the bearing cap nuts and tighten them in stages to 15 ft. lbs. (20 Nm). Remove the press tool and install the center bearing cap; tighten it in stages to 15 ft. lbs. (20 Nm).
  28.  
  29. Install the intake camshaft in the carrier with the pulley guide pin facing upwards.
  30.  
  31. Turn the distributor shaft to align the driver with the markings on the distributor housing. Install new O-rings on the housing and rotor shaft.
  32.  
  33. Using the rear bearing cap as a guide, press the cam into place with the press tool. Install the bearing caps in the original order.
  34.  
  35. Install the bearing cap nuts and tighten them in stages to 15 ft. lbs. (20 Nm). Remove the press tool and install the center bearing cap; tighten it in stages to 15 ft. lbs. (20 Nm).
  36.  
  37. Install the center nut in the cam carrier and tighten it to 15 ft. lbs. (20 Nm).
  38.  
  39. Double check the tightness of all the camshaft carrier nuts and the bearing cap nuts. All should be 15 ft. lbs. (20 Nm). Do not overtighten.
  40.  
  41. Reinstall the distributor, connect the coil wire and install the ignition wire clip at the left bolt. Remove the paper plugs from the spark plug holes.
  42.  
  43. Use a silicone sealer and apply to the front and rear camshaft bearing caps. Install new gaskets for the valve cover and the spark plug wells. Install the spark plug gasket with the arrow pointing towards the front of the car and the word "UP" facing up. Make sure the valve cover gasket is correctly positioned and install the valve cover.
  44.  
  45. Reconnect the ground wire at the distributor.
  46.  
  47. Install the ignition wires and the cover plate.
  48.  
  49. Using a compression seal driver (Volvo tool No. 5025 or similar), install the oil seals for the front of each camshaft. Camshafts MUST NOT be allowed to turn during this operation.
  50.  
  51. Install the upper backing plate over the ends of the camshafts and adjust the plate so that the cams are centered in the holes.
  52.  
  53. Replace the idler pulleys and tighten their mounts to 18.5 ft. lbs. (25 Nm).
  54.  
  55. Install the camshaft drive pulleys, using a counterhold to prevent the cams from turning.
  56.  
  57. Making sure that the camshaft pulleys are properly aligned with the marks on the backing plate, position the timing belt so that the double mark on the belt coincides exactly with the top mark on the belt guide plate (at the top of the crankshaft). Place the belt onto the cam pulleys and make sure the single marks on the belt line up exactly with the marks on the pulleys. Fit the belt over the idler pulleys; right side idler first, then the left.
  58.  



Click image to see an enlarged view

Fig. Fig. 17: Make sure all the marks align and the No. 1 cylinder is at TDC

  1. Double check that the engine is on TDC for cylinder 1 and that all the belt markings line up as they should.
  2.  
  3. Loosen the tensioner locknut. Rotate the crankshaft clockwise one full turn until the belt markings again coincide with the pulley markings.
  4.  


WARNING
The engine must not be rotated counterclockwise while the tensioner is loose.

  1. Turn the crankshaft smoothly clockwise until the pulley marks are 1 1 / 2 teeth beyond the marks on the backing plate.
  2.  



Click image to see an enlarged view

Fig. Fig. 18: Make sure the marks on the timing belt align with the pulley marks. Install the belt on the right side pulley first

  1. Tighten the tensioner locknut. Install the lower timing belt cover.
  2.  
  3. Install the radiator fan and pulley, the alternator drive belt and the negative battery cable.
  4.  
  5. Double check all installation items, paying particular attention to loose hoses or hanging wires, loose nuts, poor routing of hoses and wires (too tight or rubbing) and tools left in the engine area.
  6.  
  7. Start the engine and allow it to run until the thermostat opens. Use extreme caution--the moving timing belt is exposed!
  8.  

This engine may be somewhat noisy when started. The noise will subside as oil reaches the tappets. Do not exceed 2500 rpm while the tappets are noisy.

  1. Shut the engine off, rotate the crankshaft to bring the engine to TDC on cylinder 1 and use Volvo tool 998 8500 to check the belt tension. Correct deflection is 5.3-5.7 units when measured between the exhaust camshaft pulley and the idler. If the tension is not correct repeat Steps 51-54.
  2.  



Click image to see an enlarged view

Fig. Fig. 19: Before tightening, ensure that the cam pulleys are in the correct position-B234 engines

  1. Install the upper timing belt cover.
  2.  
  3. Start the engine and final check all functions.
  4.  

B28F and B280F Engines

See Figures 20, 21, 22 and 23

The use of the correct special tools or their equivalent is REQUIRED for this procedure. All wires and hoses should be labeled at the time of removal. The amount of time saved during reassembly makes the extra effort well worthwhile.

  1. Disconnect the negative battery cable.
  2.  
  3. Drain the coolant.
  4.  


CAUTION
When draining the coolant, keep in mind that cats and dogs are attracted by ethylene glycol antifreeze, and are quite likely to drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantity. Always drain the coolant into a sealable container. Coolant should be reused unless it is contaminated or several years old.



Click image to see an enlarged view

Fig. Fig. 20: Exploded view of the head assemblies-B27F shown, B28F engine is similar

  1. Remove the air cleaner assembly and all attaching hoses. On B28F and B280F engines, remove the intake air pre-heating hose and heat stove from the left side exhaust manifold, if that cylinder head is being removed.
  2.  
  3. Disconnect the throttle cable. On automatic transmission equipped cars, disconnect the kick-down cable.
  4.  
  5. Disconnect the EGR vacuum hose and remove the pipe between the EGR valve and manifold.
  6.  
  7. Remove the oil filler cap, and cover the hole with a rag. Disconnect the PCV pipe from the intake manifold.
  8.  
  9. Remove the front section of the intake manifold.
  10.  


CAUTION
The fuel system is under pressure. Release pressure slowly and contain any spillage. Observe no smoking/no open flame precautions

  1. Disengage the electrical connector and fuel line at the cold start injector. Disengage the vacuum hose, both fuel lines, and the electrical connector from the control pressure regulator.
  2.  
  3. Disengage the hose, pipe, and electrical connector from the auxiliary air valve and remove the auxiliary air valve.
  4.  
  5. Disengage the electrical connector from the fuel distributor. Remove the wire looms from the intake manifolds and disconnect the spark plug wires.
  6.  
  7. Disconnect the fuel injectors from their holders.
  8.  
  9. Disconnect the distributor vacuum hose, charcoal cannister hose, and diverter valve hose from the intake manifold. Also disconnect the power brake hose and heater hose at the intake manifold.
  10.  
  11. Disconnect the throttle control link from its pulley.
  12.  
  13. On cars equipped with an EGR vacuum amplifier, disconnect the wires from the throttle micro switch and solenoid valve.
  14.  
  15. At the firewall, disconnect the fuel lines from the fuel filter and return line.
  16.  
  17. Remove the two attaching screws and lift out the fuel distributor and throttle housing assembly.
  18.  
  19. On cars not equipped with an EGR vacuum amplifier, disconnect the EGR valve hose from underneath the throttle housing.
  20.  
  21. Remove the cold start injector, rubber ring and pipe.
  22.  
  23. Remove the four retaining bolts and lift off the intake manifold. Remove the rubber rings.
  24.  
  25. Remove the splash guard beneath the engine.
  26.  
  27. If removing the left cylinder head, remove the air pump from its bracket.
  28.  
  29. Remove the vacuum pump and O-ring in the valve cover. Remove the vacuum hoses from the wax thermostat.
  30.  
  31. If removing the right cylinder head, disconnect the upper radiator hose.
  32.  
  33. On air conditioned models, remove the AC compressor. Use wire to tie it out of the way. Do not disconnect the refrigerant lines.
  34.  
  35. Disconnect the distributor leads and remove the distributor. Remove the EGR valve, bracket and pipe. At the firewall, disengage the electrical connectors at the relays.
  36.  
  37. On air conditioned models, remove the rear compressor bracket.
  38.  
  39. Disconnect the coolant hose(s) from the water pump to the cylinder head(s). If removing the left cylinder head, disconnect the lower radiator hose at the water pump. Disconnect the coolant temperature sensor.
  40.  
  41. Disconnect the air injection system supply hose from the applicable cylinder head. Separate the air manifold at the rear of the engine. If removing the left cylinder head, remove the backfire valve and air hose.
  42.  
  43. Remove the valve cover(s).
  44.  
  45. On the left cylinder head, remove the Allen head screw and four upper bolts to the timing gear cover. On the right cylinder head, remove the four upper bolts to the timing gear cover and the front cover plate.
  46.  
  47. From beneath the car, remove the exhaust pipe clamps for both header pipes on the B27F. On B28 and B280, carefully remove the oxygen sensor. Then remove the downpipe/crossover pipe above the catalytic converter and at the manifolds.
  48.  
  49. If removing the right cylinder head, remove the retainer bracket bolt and pull the dipstick tube out of the crankcase.
  50.  
  51. Remove the cover plate at the rear of the cylinder head.
  52.  
  53. Rotate the camshaft sprocket (for the applicable cylinder head) into position so that the large sprocket hole aligns with the rocker arm shaft. With the camshaft in this position, loosen the cylinder head bolts in sequence (same sequence as tightening), and remove the rocker arm and shaft assembly. If both heads are to be removed, label the left and right rocker assemblies so they are returned to the matching head; they are not interchangeable.
  54.  
  55. Loosen the camshaft locking bolt (directly in back of sprocket) and slide the locking plate to one side.
  56.  
  57. It is necessary to hold the cam chain stretched during camshaft removal. Otherwise, the chain tensioner will automatically take up the slack, making it impossible to reinstall the sprocket on the cam. To accomplish this, a special sprocket retainer tool (Volvo No. 5104) is installed over the sprocket with two bolts in the top of the timing chain cover. A bolt is then screwed into the sprocket to hold it in place. For the B28F and B280F engines, use special tool No. 5213. Fasten the tool to the timing gear cover and draw tension on the chain by turning the upper knob.
  58.  



Click image to see an enlarged view

Fig. Fig. 21: Use the Volvo special tool to retain the timing sprocket and chain-shown attached to a B280 engine; B27 and B28 engines are similar

  1. Remove the camshaft sprocket center bolts and push the camshaft to the rear, so it clears the sprocket.
  2.  
  3. Remove the cylinder head.
  4.  

Do not remove the cylinder head by pulling straight up. Instead, lever the head off by inserting two spare head bolts into the front and rear inboard cylinder head bolt holes, and pulling toward the applicable wheel housing. Otherwise, the cylinder liners may be pulled up, breaking the lower seals and leaking coolant into the crankcase. If any do pull up, new liner seals must be used, and the crankcase completely drained.

  1. Remove the head gasket. Clean the contact surfaces with a plastic scraper and lacquer thinner.
  2.  
  3. If the head is going to be off for any length of time, install liner holder (Volvo special tool No. 5093) or two strips of thick stock sheet steel with holes for the head bolts, so that the liners stay pressed down against their seals. Install the holders widthwise between the middle four head bolt holes.
  4.  



Click image to see an enlarged view

Fig. Fig. 22: B28 and B280 engines must have their cylinder liners held in place. Use Volvo tool or fabricate one of heavy sheet steel

  1. When reinstalling, remember that the timing chain must be kept taut at all times. Install the guide sleeves (dowels) at the outboard corners of the block (if they were not removed, pull them up with a pair of narrow tipped pliers) and prop them up with a (3mm) drill shank inserted in the block hole. This will prevent the dowels from collapsing into the block when the head is installed.
  2.  
  3. Remove the liner holders which are clamped across the cylinders.
  4.  
  5. The right and left head gaskets are different. Remove any plugs and/or paper from the passages before placing the head gasket on the block.
  6.  
  7. Position the cylinder head on the block, making sure the guide dowels engage the holes in the head.
  8.  
  9. Slide the camshaft forward to engage the sprocket and install the center bolt. Make sure the head does not move. Double check that the cam is not caught in the locking fork and that the stud on the sprocket fits correctly into the groove in the camshaft. Remove the timing chain retainer tool.
  10.  
  11. Remove the drill bits below the guide dowels. Install the rocker arm assembly. Remember to install the rocker assemblies on the correct head if both heads were removed. The circlips (snaprings) on the end of the rocker shaft should face forward on the left side head and rearward on the right head.
  12.  
  13. The bolts threads should be clean and lightly oiled. Install the bolts finger-tight.
  14.  
  15. Tighten the bolts in the correct sequence and in three stages:
  16.  



First stage: tighten all to 7 ft. lbs. (9 Nm)
 
Second stage: tighten all to 22 ft.lbs. (30 Nm)
 
Third stage: tighten all to 44 ft. lbs. (60 Nm). Note the time of day this tightening takes place.
 



Click image to see an enlarged view

Fig. Fig. 23: Cylinder head bolt tightening sequence-B27 and B28 engines (arrow indicates front of engine)

  1. Position the camshaft locking fork and tighten its bolt.
  2.  
  3. Tighten the camshaft center bolt. Use a 10mm hex key and tighten to 52-66 ft. lbs. (71-89 Nm). Use a small bar or other tool inserted through the sprocket to keep it from turning.
  4.  
  5. Install the four upper bolts in the timing gear case. Depending on which head was installed, either install the screw plug in the left side or the cover and washer on the right side. Using a new gasket, install the cover(s) at the rear of the cylinder head(s).
  6.  
  7. If both heads were removed, install the other head by repeating Steps 40 through 49.
  8.  
  9. No less than 30 minutes after performing Step 46 (longer is better), loosen the head bolts in the same order in which they were tightened. When all are loose, tighten in the correct sequence to 13 ft. lbs. (18 Nm). The final setting is gained by tightening each bolt in the correct sequence through 115° of rotation.
  10.  
  11. With the head(s) properly tightened, check the valve lash and adjust adjust as necessary, following procedures outlined previously.
  12.  
  13. After adjusting the valves, turn the engine to its TDC/compression position. This aligns the crankshaft marks at zero and provides clearance at both valves for cylinder No. 1.
  14.  
  15. Install new gaskets and install the valve covers. Install only four bolts and do not tighten them excessively--the covers will be removed later on.
  16.  
  17. If the right cylinder head was removed, reinstall the dipstick tube and the dipstick. Secure the mounting bolt for the tube bracket.
  18.  
  19. Under the car, connect the exhaust system to the manifolds and connect the crossover pipe at the catalytic converter. Carefully reinstall the oxygen sensor.
  20.  
  21. If the left cylinder head was removed, install the backfire valve and connect the air hose. Install the air manifold at the rear of the engine.
  22.  
  23. Connect the coolant temperature sensor wiring. Install the coolant hoses to heads. Use new clamps to insure a good seal.
  24.  
  25. Install the rear compressor bracket if equipped with air conditioning.
  26.  
  27. Install the distributor making sure the rotor points toward the mark on the distributor body when installed. Place the distributor cap in position but DO NOT attach the clips or the spark plug wires. Damage may result when the intake manifold is installed.
  28.  
  29. Attach the EGR valve, bracket and pipe.
  30.  
  31. Connect the wiring to the relays at the firewall.
  32.  
  33. On air conditioned models, reinstall the compressor on its mounts. Install the belt and adjust it to the proper tension.
  34.  
  35. If the vacuum pump was removed, reinstall it, making sure the arm contacts the cam correctly. Use a new gasket and connect the hose properly.
  36.  
  37. Install the air pump if the left head was removed.
  38.  
  39. Use new rubber rings and install the intake manifold. Tighten the retaining bolts to 10 ft. lbs. (14 Nm).
  40.  
  41. Install the cold start injector with its line and seal.
  42.  
  43. Attach the fuel distributor and throttle housing assembly. Connect the EGR hose under the throttle housing.
  44.  
  45. Connect the fuel lines to the fuel filter and return lines.
  46.  
  47. Clamp down the distributor cap and install the spark plug wires.
  48.  
  49. If the car is equipped with a vacuum amplifier for the EGR system, connect the wiring to the throttle micro-switch and the solenoid valve.
  50.  
  51. Install the throttle cable to its pulley and, if automatic, the kick-down cable.
  52.  
  53. Connect the various vacuum hoses, observing the labels made during disassembly.
  54.  
  55. Connect the heater hose(s) at the intake manifold.
  56.  
  57. Reinstall the fuel injectors. Connect the wiring to the injectors and route the wiring properly along the intake manifold. Install the spark plug wires.
  58.  
  59. Install the auxiliary air valve and connect it to its wire and hose.
  60.  
  61. Connect the hose, both fuel lines and the wiring to the control pressure regulator.
  62.  
  63. Remove any plugs in the system and install the front sections of the intake manifold.
  64.  
  65. Install the oil filler cap, the air cleaner assembly, the pre-heat hoses and fittings if removed and the PCV pipe and valve.
  66.  
  67. Confirm that the draincocks in both the cylinder block and the radiator are closed and refill the engine with coolant.
  68.  
  69. Double check all installation items, paying particular attention to loose hoses or hanging wires, loose nuts, poor routing of hoses and wires (too tight or rubbing) and tools left in the engine area.
  70.  
  71. Connect the negative battery cable.
  72.  
  73. Set the dashboard temperature control to maximum heat. Start the engine and allow it to warm up to normal operating temperature. During this time, closely examine the work area for signs of leakage. Since the valve cover(s) are not tightly retained, there may be some seepage. Don't tighten them yet.
  74.  
  75. Shut the engine off and allow it to cool for 30 to 45 minutes. Remove the valve covers. It may be necessary to remove the vacuum pump from the left-hand cover.
  76.  
  77. The final setting of the head bolts is accomplished by:
    1. Observe the loosening sequence chart. Loosen the first bolt only, then tighten it to 10 ft. lbs. (14 Nm), then angle-tighten it through 115° of motion.
    2.  
    3. Repeat this procedure with the second bolt, the third and so on until all the bolts have been reset individually.
    4.  

  78.  


WARNING
DO NOT loosen all the bolts at once. Deal with each bolt individually and follow the correct sequence. If all the bolts are loosened, the head will lift and the gasket will need to be replaced.

  1. Install the valve cover(s) with all the bolts. Tighten the bolts to 10 ft. lbs. (14 Nm). Install the vacuum pump with a new gasket if it was removed. Make sure the pump shaft meshes on top of the cam shaft.
  2.  
  3. Restart the engine. Check the ignition timing and idle speed and adjust if necessary. Install the splash shields.
  4.  

D24 and D24T Engines

See Figures 24, 25, 26, 27 and 28

Due to the number of special tools needed to perform this operation, it is recommended that timing belt removal and installation be performed by a competent garage. However, if you have access to the required special tools, the procedure is given below.

  1. Disconnect the negative battery cable.
  2.  
  3. Remove the splash guard and disconnect the exhaust pipe at the manifold and its transmission bracket. On the D24T model, disconnect all hoses to the turbocharger, and plug any open ports and hoses.
  4.  
  5. Remove the expansion tank after draining the radiator. Disconnect the lower hose at the cold start device on the fuel injection pump and point the end of the hose down to drain the block.
  6.  


CAUTION
When draining the coolant, keep in mind that cats and dogs are attracted by ethylene glycol antifreeze, and are quite likely to drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantity. Always drain the coolant into a sealable container. Coolant should be reused unless it is contaminated or several years old.

  1. Disconnect all remaining coolant hoses from the engine. Remove the vacuum pump and its plunger from the left side of the cylinder head.
  2.  
  3. Clean and remove the fuel delivery pipes. Plug all openings to prevent dirt contamination.
  4.  
  5. Disconnect the wire for the temperature gauge, the glow plug wires, the wire bundle for the rear glow plugs, the return hose from the rear injector, and the wire for the temperature gauge sender at the rear of the head.
  6.  
  7. Remove the valve cover and remove the front and rear timing belt cover.
  8.  
  9. Set the engine on No. 1 cylinder TDC compression stroke. Both camshaft lobes for cylinder no. 1 should point up at equally large angles and the flywheel timing pointer should be aligned with the 0 mark on the flywheel.
  10.  



Click image to see an enlarged view

Fig. Fig. 24: Set the engine on No. 1 cylinder TDC compression stroke, and ensure that the camshafts and timing pointer are in the correct position

  1. Remove the timing gear belt from the front camshaft gear by loosening the retaining bolts for the coolant pump and belt idler pulley.
  2.  
  3. Using a wrench to hold the gear (special tool No. 5199), remove the front gear center bolt. Do not allow the camshaft to turn at all. Remove the gear by tapping it off the camshaft.
  4.  
  5. Remove the injection pump drive belt by loosening the retaining bolts for the injection pump bracket to release belt tension. Tighten one bolt to hold the pump in the upper position after the belt is removed.
  6.  



Click image to see an enlarged view

Fig. Fig. 25: Remove the injection drive pump by loosening the retaining bolts for the pump bracket

  1. Remove the camshaft rear gear center bolt and gear while holding the gear with a wrench (special tool No. 5199). Access to the center bolt will be easier if special tool No. 5201 is used. Make sure the camshaft does not rotate.
  2.  
  3. Remove the cylinder head bolts and remove the cylinder head. Position the head on wooden blocks so that the valves do not hold the weight of the head.
  4.  
  5. Use a steel ruler to check for head warpage. Lengthwise warpage cannot exceed 0.008 in. (0.2mm) and crosswise warpage cannot exceed 0.002 in. Warpage in excess of these tolerances requires replacing the head; it cannot be resurfaced.
  6.  

To install:
  1. Remove the rear glow plug so that it does not strike the injection pump bracket when installing.
  2.  
  3. Install special dowel pins (to center the head on the block) in the front and rear head bolt holes on the injection pump side of the engine (special tool No. 5189).
  4.  



Click image to see an enlarged view

Fig. Fig. 26: Head gasket thickness is indicated by 1, 2 or 3 notches in the gasket

  1. Install the new head gasket. There are three different thicknesses for gaskets, indicated by 1, 2 or 3 notches in the gasket. Use a gasket with the same No. of notches as were on the gasket just removed. Any time pistons, connecting rods or crankshaft are repaired or disassembled, piston projection above the block deck must be measured and an appropriate gasket selected.

    Piston Projection: 0.026-0.031 in. (0.66-0.78mm); 1 Notch; Gasket thickness; 0.055 in. (1.4mm)
     
    Piston Projection: 0.032-0.035 in. (0.81-0.89mm); 2 Notches; Gasket thickness; 0.059 in. (1.5mm)
     
    Piston Projection: 0.036-0.040 in. (0.91-1.00mm); 3 Notches; Gasket thickness; 0.063 in. (1.6mm)
     

  2.  

  1. Set the engine to No. 1 cylinder TDC, if not already set.
  2.  



Click image to see an enlarged view

Fig. Fig. 27: Set the No. 1 cylinder to TDC as indicated by the pointer shown

  1. Set the camshaft in position on the head so that both camshaft lobes on No. 1 cylinder point up at equally large angles (both valves closed). Lock the camshaft in this position by installing special tool No. 5190 in the slot in the rear of the camshaft.
  2.  
  3. Install the cylinder head. Install several of the head bolts, remove the dowel pins and install all of the head bolts. The threads and washers on the bolts should be oiled before installation. Tighten the bolts in two stages in the sequence shown: first all to 30 ft. lbs. (41 Nm), then all to 65 ft. lbs. (88 Nm).
  4.  
  5. From late 1980, new cylinder head bolts are used on the D24 Diesel. They are longer and 1mm wider. Torquing these bolts is a 6 step procedure:
    1. Tighten to 30 ft. lbs. (41 Nm)
    2.  
    3. Tighten to 44 ft. lbs. (60 Nm)
    4.  
    5. Tighten to 55 ft. lbs. (75 Nm)
    6.  
    7. Tighten 180°, in one movement, without stopping.
    8.  
    9. Run engine until oil temperature is minimum 120°F.
    10.  
    11. Tighten 90°, in one movement, without stopping.
    12.  

  6.  



Click image to see an enlarged view

Fig. Fig. 28: Diesel cylinder head bolt tightening sequence; follow the reverse order (starting at No. 14) when loosening the bolts

  1. Install the bolts for the front belt shield.
  2.  
  3. Use wrench 5199 to hold the rear gear and use wrench 5201 to remove its center bolt. Remove the rear camshaft gear and remove the cover gasket.
  4.  
  5. Remove the front camshaft gear bolt using tool No. 5199 to hold the gear in position. Do not allow the camshaft to turn. Tap the gear loose.
  6.  
  7. Verify that No. 1 cylinder is still at TDC.
  8.  
  9. Using the cooling pump movement, adjust the belt tension. Install belt tension gauge 5197 on the belt. Set the gauge to 12.5. Adjust belt tension with the water pump until the mark on the plunger is flush with the gauge sleeve.
  10.  
  11. Press heavily on the belt with your hand and once again check the belt tension. Adjust if necessary.
  12.  
  13. Using wrench 5199 to hold the gear, tighten the front gear center bolt to 33 ft. lbs. (45 Nm).Make sure the camshaft does not rotate.
  14.  
  15. Remove the feeler gauge and the lock gauge at the rear of the engine.
  16.  
  17. Remaining installation proceeds in the reverse order of removal. After driving 600-1200 miles retighten the head with the engine warm to 62 ft. lbs. (84 Nm). Do not loosen the head bolts before retightening.
  18.  

CLEANING & INSPECTION



See Figure 29

  1. Clean all components parts with a suitable parts cleaner.
  2.  
  3. Remove the carbon deposits in the combustion chambers using a liquid carbon dissolving solvent. Clean the cylinder head face with a soft plastic scraper and paint remover or a liquid gasket striper.
  4.  
  5. Check the cylinder head(s), valve seats and valve guides for damage or cracks. You may wish to take the head to professional machine shop for chemical or dye crack checking. Cracks can occur internally where they cannot be seen with the naked eye.
  6.  



Click image to see an enlarged view

Fig. Fig. 29: An electric drill equipped with a wire wheel will expedite complete gasket removal

CHECKING FOR HEAD WARPAGE



See Figures 30 and 31

Lay the cylinder head down with the combustion chamber facing up. Place a straightedge across the gasket surface of the head, both diagonally and straight across the center. Using a flat feeler gauge, determine the clearance at the center of the straightedge. If the warpage exceeds 0.002 in. (0.05mm) in a span of 4 in. (100mm), the cylinder head must be replaced.

If the cylinder head exceeds specification it must be replaced; it cannot be machined.



Click image to see an enlarged view

Fig. Fig. 30: Check the cylinder head for warpage along the center using a straightedge and a feeler gauge



Click image to see an enlarged view

Fig. Fig. 31: Be sure to check for warpage across the cylinder head at both diagonals

 
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