Cylinder Head Cleaning and Inspection

Cylinder Head Cleaning and Inspection

Special Tools

* EN-28410 - Gasket Remover

* EN-47909 - Injector Bore and Sleeve Cleaning Kit

* J 9666 - Valve Spring Tester

For equivalent regional tools, refer to Special Tools Special Tools.




1. Clean the cylinder head of all foreign material.

2. Clean the threaded holes.

3. Clean the injector bores using EN-47909 - injector bore and sleeve cleaning kit.

Caution: Do not use any power type sanding devices, a wire brush or wheel, or chemical cleaning agents on gasket surfaces. Engine damage may result.

4. Clean the cylinder head gasket sealing surface.

1. Use the EN-28410 - remover or equivalent to carefully clean the gasket sealing surface of large sealing or corrosion matter. When scraping, take care not to scratch or gouge the metal surfaces. Do not push the debris into oil, coolant, and combustion openings or bolt holes.

2. Inspect the gasket sealing surfaces for corrosion, especially in the areas that were in contact with the crimped tabs of the first generation head gasket. If corrosion is present, continue with the rest of the steps in this procedure for proper cleaning.

3. For surfaces that have corrosion or pitting, wrap a piece of flat steel (4"x 2" or larger) with 600 grit wet grade sand paper. Using Moisture Displacing Lubricant, refer to Adhesives, Fluids, Lubricants, and Sealers Adhesives, Fluids, Lubricants, and Sealers, wet sand the block surface to remove any remaining gasket material or corrosion. Do not use any paper coarser than 600 grit.

4. Take care to keep the sanding block parallel to the block surface and evenly sand the sealing surface. Some areas of corrosion will still show a stain. Do not attempt to wet sand these areas down to a shiny metal surface.

5. Change the sanding paper when it becomes clogged. Carefully and frequently wipe the surface, using a clean cloth each time, to prevent sanding debris from building up and contaminating the oil and coolant cavities.

6. Clean the head gasket surfaces with Brake Parts Cleaner, refer to Adhesives, Fluids, Lubricants, and Sealers Adhesives, Fluids, Lubricants, and Sealers, to remove any traces of oil or debris.

5. Inspect the cylinder head for the following:

* Damage to the gasket surfaces

* Damage to the threaded bolt holes

* Cracks in the exhaust ports

* External cracks in the water chamber

* Cracks between the valve seats

* Restrictions in the intake or exhaust passages

* Restrictions in the cooling system passages

* Rusted, damaged or leaking core plugs

6. Measure the cylinder head for warpage with a straight edge and a feeler gauge. A cylinder head block deck with warpage in excess of 0.1 mm (0.0039 in) must be replaced.




7. Measure the cylinder head exhaust manifold deck for warpage. A cylinder head exhaust manifold deck with warpage in excess of 0.1 mm (0.0039 in) within a 453 mm (17.83 in) area must be replaced.




8. Measure the cylinder head intake manifold deck for warpage. A cylinder head intake manifold deck with warpage in excess of 0.3 mm (0.011 in) within a 493 mm (19.41 in) area must be replaced.




9. Measure the valve spring tension using J 9666 - valve spring tester. Replace the valve spring if the valve spring tension is less than 275 N (61.8 lb) at 41 mm (1.6142 in)




10. Measure the valve spring for squareness. Replace the valve spring if squareness is beyond 2.0 mm (0.0787 in).




11. Measure the valve spring free length. The production free length is 56.6 mm (2.2283 in).

12. Measure the valve stem to guide clearance.

1. Set a dial indicator to the valve stem measuring point.

2. Move the valve stem from side to side while reading the total movement on the dial indicator. If the measured valve exceeds 0.20 mm (0.0079 in), replace the cylinder head.




13. If the valve stem to guide clearance is over 0.25 mm (0.098 in) for the exhaust valve guides or 0.20 mm (0.0079 in) for the intake valve guides, the cylinder head must be replaced.

14. Inspect the valves for the following:

* Bent valve stem

* Scored valve stem

* Worn valve key grooves

* Pitted surfaces




15. Measure the valve margin. The intake valve production margin is 1.2 mm (0.0472 in) and the service limit is 0.88 mm (0.0346 in). The exhaust valve production margin is 1.0 mm (0.0394 in) and the service limit is 0.73 mm (0.0287 in). Replace the valve if the valve margin is below the service limit.




16. Measure the valve depression.

1. Insert a new valve into the cylinder head (1).

2. Use a depth gauge or a straight edge to measure the valve depression from the cylinder head gasket surface (2). The intake valve depression is 0.6 mm (0.0236 in) and the service limit is 2.5 mm (0.0984 in). The exhaust valve depression is 0.9 mm (0.0354 in) and the service limit is 2.0 mm (0.0787 in). Recondition the valve seat if the valve depression is above specifications.




17. Measure the valve contact width.

* Inspect the valve contact area for roughness or unevenness.

* The intake valve contact width is 2.1 mm (0.0827 in) and the service limit is 2.5 mm (0.0984 in).

* The exhaust valve contact width is 2.1 mm (0.0827 in) and the service limit is 2.5 mm (0.0984 in).

* Recondition the valve seats to bring the contact width into specifications.