Cylinder Head - Disassemble

Refer to Updated Surface Preparation and Torque Specs.Updated Surface Preparation and Torque Specs - TSB 276113

DISASSEMBLE
1. Valve mechanism.
2. Cylinder head plugs (2) (94).
3. Cup plug (109), if damaged or leaking.
- Obtain a suitable self-threading screw.
- Drill a hole in the plug.
- Install the self-threading screw.
- Pry out plug.
4. Spark plugs.

CAUTION: Do not remove spark plugs from an aluminum cylinder head until the cylinder head has cooled.

- Clean dirt and debris from spark plug recess area.
- If spark plug opening threads are damaged and NOT restorable with a "Thread Chaser", replace the cylinder head.

CAUTION: Do not install thread inserts into the spark plug openings. If thread inserts are installed into the spark plug openings, severe engine damage will occur.

CYLINDER HEAD INSPECTION
Inspect oil flow check valve (5) (do not remove valve to inspect).
Inspect cylinder head gasket and mating surfaces for leaks, corrosion and blow-by. If the gasket has failed, determine the cause:
- Improper installation.
- Loose or warped cylinder head.
- Missing, off location or not fully seated dowel pins.
- Machine stamps in seal area around coolant passages.
- Chips in cylinder head bolt holes.
- Bolt holes in cylinder block not drilled or tapped deep enough.

CLEAN

CAUTION: Safety glasses must be worn when using a power wire brush to avoid injury to the eyes.

- Cylinder head bolts.
- Cylinder head. Remove all varnish, soot and carbon to the bare metal. DO NOT use a wire brush on any gasket sealing surface.
- Valve guides.
- Threaded holes.
- Remains of sealer from plug holes.

INSPECT
1. Cylinder head bolts for damaged threads or stretching and damaged heads caused by improper use of tools.

CAUTION: Suspect bolts must be replaced.

2. Cylinder head for cracks, especially between valve seats and in the exhaust ports.
3. Cylinder head deck for corrosion, sand inclusions and blow holes.

NOTE: Do not attempt to weld the cylinder head, replace it.

Checking Cylinder Head Flatness:

4. Cylinder head deck, intake and exhaust manifold mating surfaces for flatness.
5. All threaded holes for damage. Threads may be reconditioned, except spark plug opening threads, with thread inserts.
6. Sealing surfaces.
- Cylinder head plug (109).
7. Valve seats for excessive wear and burned spots.
- Valve seats may be reconditioned by grinding. An oscillating type valve seat grinder is preferred. Follow the grinder manufacturer's instructions.

If, after grinding, the new seat is too wide, it may be narrowed by using a 20° or 70° stone. The 20° stone will lower the seat and the 70° stone will raise the seat.

- Since the valve guide serves to support and center the valve grinder, it is essential that the valve guide is cleaned properly. If the valve guide requires reaming, this must be done first.