S46, S56, S66, RB75 +4X4

Phaser Engine Sections 12A-01 to 12A-05

Cylinder head assembly

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12A-01
To remove and to fit

Rocker cover / (Rocker Assembly / Valves Below)
To remove
1 Disconnect the breather pipe.

2 Remove the cap nuts and the sealing washers from the top of the rocker cover.

3 Lift off the rocker cover and the joint together with the rocker cover seal, which is fitted between the rocker cover and the induction manifold.

4 When the rocker cover is fitted, the cap nuts are tightened onto the nuts of the rocker brackets. During removal of the cap nuts, it is possible to loosen the nuts of the rocker brackets and these nuts should be checked for tightness every time the cover is removed.

To fit
1. Check the condition of the rocker cover joint and the sealing washers and clean the joint face of the cylinder head. If necessary, the joint can be removed and a new joint fitted with a suitable adhesive.

2. Fit the rocker cover together with the seal (Al) which is fitted between the rocker cover and the induction manifold. Fit the seals and the cap nuts (A2). Tighten the cap nuts to 20 Nm (15 lbf ft) 2,1 kgf m. If the cap nuts are tightened too much the cap nuts can fasten on the nuts for the rocker shaft brackets

12A-02

Rocker assembly

To remove and to fit

12A-01

To remove

1. Remove the rocker cover.

2 . Release evenly and gradually the fasteners of the rocker shaft brackets; begin with the end brackets and move toward the centre. Remove the fasteners and the washers and lift off the rocker assembly.

3. Remove the rubber oil seal (B) from the oil supply connection or the oil supply hole in the cylinder head.

To fit
I. Fit a new rubber oil seal in the oil supply hole in the cylinder head.

2. Check that the push rods fit correctly in the sockets of the tappets. Fit the rocker assembly; ensure that the oil supply connection is fitted correctly into the oil seal. Check that the ends of the adjustment screws fit correctly in the sockets of the push rods.

3. Fit the washers and fasteners of the rocker shaft brackets and tighten the fasteners evenly and gradually; begin with the inner fasteners and work towards the end fasteners. Ensure that all the fasteners are tightened evenly to the correct torque.

12A-03

To dismantle and to assemble

To dismantle
1. Remove the clips from both ends -of the rocker shaft. Ensure that the ends of the rocker shaft are not damaged. Release the location screw for the oil supply connection.
2. Dismantle the assembly and make a note of the position of each component to ensure that they can be assembled more easily.

To assemble
1. Ensure that the oil holes in the rocker shaft and in the rocker levers are not restricted.
2. Lubricate the components with clean engine lubricating oil before assembly. Assemble the components in the correct order (A) and ensure that the location screw for the oil supply connection is fitted correctly in the rocker shaft. Fit the clips to the ends of the rocker shaft.

12A-04

To inspect and to correct

To inspect
1. Clean and inspect all the components for wear and any other damage. Check the clearance of the rocker levers on the rocker shaft. If the clearance is larger than 0,13 mm (0.005 in), renew the rocker lever bush and/or the rocker shaft.

To correct
1. To renew the rocker lever bush, press out the old bush with a suitable mandrel.
2. Press in the new bush with the lubrication hole in the bush on the same side as that in the rocker lever and aligned with it.
3. Ream the bush in the rocker lever to give a clearance on the rocker shaft of 0,03/0,09 mm (0.001/0.004 in).

The valve tip clearance is measured between the top of the valve stem and the rocker lever (A). With the engine cold, the correct clearances are 0,20 mm (0.008 in) for the inlet valves and 0,45 mm (0.018 in) for the exhaust valves. See B for the position of the valves.

Four cylinder engines
1 Turn the crankshaft in the normal direction of rotation until the inlet valve of number 4 cylinder has just opened and the exhaust valve of the same cylinder has not fully closed.Check the clearances of the valves of number 1 cylinder and adjust them, if necessary.

2 With the valves of number 2 cylinder set as indicated above for number 4 cylinder, check/adjust the clearances of the valves of number 3 cylinder.

3 With the valves of number 1 cylinder set, check/adjust the clearance of the valves of number 4 cylinder.

4 With the valves of number 3 cylinder set, check/adjust the clearances of the valves of number 2 cylinder.

Six cylinder engines
1 Turn the crankshaft in the normal direction of rotation until the inlet valve of number 6 cylinder has just opened and the exhaust valve of the same cylinder has not fully closed. Check the clearances of the valves of number 1 cylinder and adjust them, if necessary.

2 With the valves of number 2 cylinder set as indicated above for number 6 cylinder, check/adjust the clearances of the valves of number 5 cylinder.

3 With the valves of number 4 cylinder set, check/adjust the clearances of the valves of number 3 cylinder.

4 With the valves of number 1 cylinder set, check/adjust the clearances of the valves of number 6 cylinder.

5 With the valves of number 5 cylinder set, check/adjust the clearances of the valves of number 2 cylinder.

6 With the valves of number 3 cylinder set, check/adjust the clearances of the valves of number 4 cylinder.

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