20405952 Volvo.Penta Retainer

1 Rocker cover2 Rocker stay bolt3 Rocker arm/rocker shaft assembly4 Snap ring5 Rocker arm6 Rocker stay7 Rocker spring8 Rocker shaft KEY POINTS FOR DISASSEMBLY(1) Removing Rocker Arm/Rocker Shaft Assembly(a) Loosen the rocker arm adjusting screws by approximately one turn each.
Removing rocker stay bolt(b) Remove the rocker stay bolts, then remove the rocker arm/rocker shaft assembly.
Removing rocker arm/rocker shaft assembly(2) Disassembling Rocker Arm/Rocker Shaft AssemblyWhen removing the rocker arms, arrange them in a line matching their installed positions to ensure that they are later refitted in the correct sequence. The rocker arms must be refitted in their original positions to prevent changes in the clearances between the rocker arms and rocker shaft.
Disassembling rocker arm/rocker shaft assembly1.2 Inspection and Repair
Points to check on rocker arm/rocker shaft assembly KEY POINTS FOR INSPECTION AND REPAIR Measuring Rocker Arm-to-Rocker Shaft ClearancesMeasure the rocker arms' inside diameters and the rocker shaft's outside diameter, and calculate the clearances from the measurements. Replace any rocker arm where the clearance exceeds the specified limit.
Unit: mm (in.)
Measuring rocker arm inside diameter and rocker shaft outside diameter1.3 Assembly
Tightening torques and oil application locationsPerform assembly by following the disassembly sequence in reverse: KEY POINTS FOR ASSEMBLY(1) Assembling Rocker Arm/Rocker Shaft AssemblyInstall each pair of rocker arms such that the identification mark (a hole with a diameter of 3 mm (0.12 in.)) is positioned on the side closer to the front of the engine.
Rocker shaft identification mark(2) Adjusting Valve Clearances(a) Loosen the rocker arm nut, then adjust the clearance to the standard value using the adjusting screw and a thickness gauge.
Unit: mm (in.)(b) Hold the adjusting screw in position while tightening the nut.
When adjusting the valve clearances after performing disassembly and reassembly, turn the crankshaft two or three times then check again that the clearances are within specification.
Adjusting valve clearance2. Cylinder Head and Valves
2.1 Disassembly
Cylinder head and valve disassembly sequence1 Push rod2 Main bolt3 Sub-bolt4 Cylinder head5 Cylinder head gasket6 Valve retainer lock7 Retainer8 Valve spring9 Valve (intake/exhaust)10 Valve stem seal11 Valve guide (Remove if it appears defective.) KEY POINTS FOR DISASSEMBLY(1) Removing Cylinder Head(a) Withdraw the push rods.
Withdrawing push rods(b) Loosen the cylinder head bolts in the sequence shown in the drawing. Go through the sequence two or three times, loosening the bolts a little each time. Do not completely remove any bolt in isolation. In the event of a cylinder head fault, use a torque wrench to check the bolts for looseness before deciding to remove them.
Cylinder head bolt loosening sequence(c) Lift the cylinder head assembly straight upward to remove it. If the cylinder head gasket sticks to the cylinder head assembly and cylinder block and prevents them from being separated, tap the thickest parts on the sides of the cylinder head using a plastic-faced hammer.
Removing cylinder head assembly(2) Removing Valves and Valve Springs(a) Use a valve lifter (commercially available) to compress the valve spring, then remove the valve lock.(b) Remove the retainer, spring, and valve. Keep together the valves and other parts for each cylinder after removing them. Do not allow parts for different cylinders to become mixed up.
Removing valve spring(3) Removing Valve Stem SealsGrip and remove each valve stem seal (1) with pliers. Do not reuse any valve stem seal.
Removing valve stem seal2.2 Inspection and Repair
Points to check on valves, cylinder head, and push rods KEY POINTS FOR INSPECTION AND REPAIR(1) Valves and Valve Guides(a) Measure the valve stems' outside diameters and the valve guides' inside diameters, and calculate the clearances from the measurements. If any clearance exceeds the specified limit, replace the valves and valve guides or the cylinder head assembly.
Unit: mm (in.) Before taking measurements, remove any carbon deposits from the valves and valve guides.
Measuring valve stem outside diameter
Measure valve guide inside diameter(b) Replacing Valve Guides1) Remove the valve guide by using a press and a suitably shaped implement to push it from the bottom of the cylinder head toward the top.2) Install a new valve guide from the top of the cylinder head using a press. After installation, the valve guide should protrude by the dimension shown in the drawing.3) Insert a new valve and make sure it slides properly.4) Inspect the contact pattern of the valve and valve guide.
Press-fitted height of valve guide(2) Valves and Valve Seats(a) Inspecting Valve Faces1) Apply a thin coat of minimum to the valve face, then use a valve lapper (commercially available) to strike the valve against the valve seat once. Inspect the contact pattern indicated by the minimum.
Inspecting valve face2) The minimum should indicate uniform contact with the valve seat in the middle of the valve face (as seen from the side). If the contact pattern is poor, grind the valve face and valve seat using a valve refacer.
Valve seat-to-valve face contact pattern3) If the valve margin width (the thickness of the valve head outer edge) is out of specification, replace the valve.
Unit: mm (in.)4) If the valve head sinkage is out of specification, rectify the valve seat or replace the cylinder head assembly.
Unit: mm (in.)
Valve head sinkage(b) Valve Face Rectification1) Use a valve refacer to grind the valve face at an angle of 45°.2) Do not reduce the valve margin width below the specified minimum dimension. If the required valve margin cannot be maintained, replace the valve.
Rectifying valve face(c) Valve Seat Rectification1) Before rectifying any valve seat, check the valve guide-to-valve clearance. If necessa