Overhaul

Measuring And Reconditioning The Cylinder Head

Special Tools: 998 6052, 999 5219, 999 5222, 999 5379, 999 5748, 999 5764.

NOTE: The illustrations in this service information are used for different model years and/or models. Therefore there may be some variation. However, the essential information in the illustrations is always correct.

Removing Valve Lifters







- Lift out the valve lifters. Mark up the valve lifters so that the original positions can be established.
- Use a suction cup to remove the valve lifters.
- Check for wear on the valve lifters. Measure if necessary.

Removing Valves
Use valve spring compressor 998 6052 with attachment claw 999 5748.







Remove
- the valve locks
- the upper valve collars
- the valve springs
- the valves.

NOTE: Keep track of the position of the moving parts.

Removing Valve Stem Seals







- Use tool 999 5219.
- Remove the valve stem seals and the lower valve collars.

Clean The Cylinder Head:
- the gasket faces
- the combustion chambers
- the inlet and exhaust ports
- the valve seats.

Checking The Cylinder Head







- Clean the spark plug threads (tap M14 x 1.25).
- Clean the valves, valve springs and collars.
- Visually check for damage.
- Regrind the seats if unsure about cracks.

Checking The Cylinder Head For Distortion
Measure cylinder head distortion Use a steel ruler and feeler gauge.

Checking For Wear In The Valve Guides







Measure the wear in the valve guides. Use a dial indicator and magnetic holder. Lift the valve approximately 2 - 3 mm from the seat when carrying out the check.

Checking The Height Of The Valve Stems







- Use camshaft adjustment tool 999 5222.
- Position the camshaft adjustment tool in the camshaft bearing recesses.
- Measure the height of the valve stem using a feeler gauge through the hole in the camshaft adjustment tool.

Installing Valve Stem Seals







- Lubricate the valve stems and the upper ends of the valve guides.
- Install
- the lower valve spring collars
- the valves in their positions.

- Install the protective sleeve (included in the gasket kit) on the valve stem.

NOTE: The protective sleeve must be installed on the valve stem when the valve stem seal is installed.

- Lubricate the protective sleeve (1) and install it on the valve stem.







- Lubricate the valve stem seal (2).
- Press down the seal past the protective sleeve with your finger.
- Press the seal down. Use tool 999 5764. Press down by hand until the tool stops against the lower valve spring washer.
- Remove the tool. Pull off the protective socket.

Installing Valve Springs







- Install the valve spring. Install the valve spring washer.
- Compress the valve spring so that the three valve lock tracks are visible. Use valve spring compressor 998 6052 with attachment claw 999 5748.

NOTE: Do not compress more than is absolutely necessary. The valve stem seal may be damaged.

- Install the valve locks.
- Check that valve locks are in the correct position when the spring is not loaded.
- Repeat the procedure with the remaining valves.