Volvo Diesel Engine Valve Inspection and Replacement

Oct. 18, 2019

Valve Guides, Inspection

TAD752GE, TAD753GE, TAD754GE

Tools:

9999696 Magnetic stand

9989876 Dial indicator

1 Remove the cylinder head; refer to Cylinder Head, Removal page 34.

2 Remove the valve stem seals from the valve guides.

3 IMPORTANT!

The cylinder head must not be put down such that its entire weight rests on the valve guides. Place the cylinder head on the bench with the valve discs facing upwards.

4 Place a new valve in the valve guide with the valve stem end in the same plane as the edge of the guide. Use a suitable spacer under the valve stem.

5 Place 9989876 Dial indicator and 9999696 Magnetic standso that the dial indicator tip is touching the valve disc edge. Move the valve sideways, in the direction of the exhaust or inlet duct. Read off the value on the dial indicator.

6 Check all valve guides. If the readings exceed the values noted in the specifications, the valve guide must be changed, refer to Administration page 11.

Valve Guides, Replacing

TAD752GE, TAD753GE, TAD754GE

Tools:

88800379 Drift

88800380 Drift

Remove the cylinder head; refer to: Cylinder Head, Removal page 34.

Remove the valves according to: 21-1, Cylinder Head Valve, Change.

CAUTION!

Risk of eye injury. Eye protection required. Removal

NOTICE! If the valve seats must also be changed, this must be done before the valve guides are removed.

1 Place the cylinder head in a hydraulic press.

2 Press out the valve guides using 88800380 Drift.

NOTICE! This can be done from the top of the cylinder head. Check for damage before pressing

the guide out.

Installation

3 Heat the cylinder head with hot water while cooling the valve guides with e.g. dry ice.

4 Lubricate the cylinder head valve guides with engine oil.

Press the valve guides in using 88800379 Drift.

5 Press until the tool bottoms against the cylinder head plane. Because valve guides are not pre-sized, further machining is necessary to achieve the correct clearance according to: Administration page 11.

6 IMPORTANT!

Once the valve guides have been changed, the cylinder head must be cleaned to prevent particles from entering the fuel and oil ducts. Contamination may cause injector malfunction or failure.

7 Install the valves according to: 21-1, Cylinder Head Valve, Change.

8 Install the cylinder head; refer to Cylinder Head, 8 Removal page 34.

21-5 Timing Gears and Shaft

Sensors, Adjustment

TAD550GE, TAD551GE, TAD750GE, TAD751GE

1 Check the gap between the sensor and the reluctor wheel with a feeler gauge.

The gap must be: 0.6 ± 0.1 mm (0.024 ± 0.004"). Adjust the sensor if the gap is wider or narrower.

2 Clean and unbolt the holder.

3 NOTICE! Different bolt lengths.

Install the holder and tachometer sensor. Brush locking fluid on the bolts and tighten them by

hand.

M8 x 45 mm (1)

M8 x 40 mm (2)

4 Adjust sensor distance from the reluctor wheel using a feeler gauge. Press lightly on the back of the sensor until the gap between the reluctor wheel and the sensor is 0.6 ± 0.1 mm (0.024 ± 0.004").

5 Allow the feeler gauge to remain in place and apply light pressure to the sensor.

Tighten the bolts.

Tightening torque: 20 Nm (14.8 lbf. ft.)

21-6 Crank Mechanism

Gear Ring, Fywheel: Replace

Flywheel removed.

IMPORTANT!

Do not drill the flywheel - risk for imbalance.

1 Drill 1–2 holes between two teeth on the ring gear. Split the ring gear at the drilled hole, using a cold chisel. Lift the gear ring away from the flywheel.

2 Brush the flywheel contact surface clean with a steel wire brush.

3 Heat the new gear ring to 180 - 200°C ( 356 –392°F) with a welding torch or in an oven. The ring gear must be evenly heated. Be careful not to heat the gear ring too much and anneal it.

Check the heat by polishing the ring bright at several places. Stop heating when the polished surfaces blue.