Cylinder Head Cleaning and Inspection

Tools Required
• SA91101NE Feeler Gage Set
• SA9177NE Straight Edge (24 inch)
• SA91102NE Gage Ball Set
• SA9179NE Dial Indicator

1. Clean the top of the pistons and the top of the block:

Important

Cover the front of the engine with a shop towel to prevent debris from entering the oil gallery holes and pan.

1. Turn the crankshaft and bring each piston to top dead center (TDC). Using a gasket scraper, remove all of the carbon from the piston top.





Caution

Protect yourself by wearing safety glasses, earplugs, a respirator, gloves, and safety shoes while performing work on the vehicle.

2. Remove all of the gasket material from the top of the block using a plastic or wood scraper.
3. Blow the carbon and oil from the bolt holes.





Notice

Be careful not to scratch or score the cylinder block and head aluminum surfaces when cleaning.

Notice

Intake and exhaust manifold stud threads can be damaged during removal and must be replaced when a new machined cylinder head casting is installed.

2. Using a plastic or wood gasket scraper, remove all of the gasket material from the manifold and head surface.





Notice

Be careful not to scratch the head gasket contact surface when cleaning the cylinder head.

3. Using a wire brush, remove all of the carbon from the combustion chambers.




4. Using a valve guide bushing brush and solvent, clean all of the valve guide bushings.
5. Using a soft brush and solvent, thoroughly clean the cylinder head:
1. Intake and exhaust ports
2. Intake and exhaust valve seats and guides




6. Inspect the cylinder head for flatness. Using a SA9177NE or equivalent and a SA91101NE or equivalent, measure the surfaces contacting the cylinder block and manifolds for warpage. If warpage is greater than the maximum, replace the cylinder head.
Specifications
Cylinder Block Side Maximum Warpage Specifications
• Transverse Standard: 0.03 mm (0.0012 in)
• Transverse Service Limit: 0.05 mm (0.002 in) max.
• Longitudinal Standard: 0.07 mm (0.028 in)
• Longitudinal Service Limit: 0.1 mm (0.004 in) max.
Specifications
Intake Manifold Side Maximum Warpage Specifications
• Longitudinal Standard: 0.1 mm (0.004 in)
• Longitudinal Service Limit: 0.15 mm (0.006 in) max.
Specifications
Exhaust Manifold Side Maximum Warpage Specifications
• Longitudinal Standard: 0.1 mm (0.004 in)
• Longitudinal Service Limit: 0.15 mm (0.006 in) max.
Specifications
EGR Flange Maximum Warpage Specifications
• Standard: 0.1 mm (0.004 in)
• Service Limit: 0.15 mm (0.006 in) max.




7. Inspect the cylinder head for cracks. Using a dye penetrate, check the combustion chamber intake and exhaust ports, head surface, and the top of the head, around all bolt holes, for cracks. If cracked, replace the cylinder head.




8. Clean the valves. Using a gasket scraper, or wire brush, remove any carbon from the valve head.





Important

A small scratch, score, or scuff on the valve stem will damage and wear out the valve stem seal.

9. Inspect valve stems and guides for wear, scratches, and burrs.




1. Using a SA91102NE or equivalent, measure the inside diameter of the valve guide bushing at 3 locations.
Specifications
Guide Bushing Inside Diameter
• Standard: 6.987-7.013 mm (0.2751-0.276 in)
• Service Limit: 7.05 mm (0.277 in) max.




2. Using a micrometer, measure the diameter of the valve stem.
Specifications
Valve Stem Diameter
• Intake Standard: 6.949-6.962 mm (0.2736-0.2741 in)
• Intake Service Limit: 6.931-6.95 mm (0.2729-0.2736 in)
• Exhaust Standard: 6.937 mm (0.273 in) min.
• Exhaust Service Limit: 6.919 mm (0.272 in) min.
3. Subtract the valve stem diameter measurement from the valve guide bushing inside diameter measurement. If the clearance is greater than maximum, replace the valve and guide bushing.
Specifications
Oil Clearance
• Intake Standard: 0.025-0.064 mm (0.001-0.0025 in)
• Intake Service Limit: 0.115 mm (0.0044 in) max.
• Exhaust Standard: 0.037-0.082 mm (0.0015-0.0032 in)
• Exhaust Service Limit: 0.131 mm (0.005 in) max.





Important

Lifter bores are machined surfaces and must not be damaged when installing valve guides, valves, seals, caps, retainers, and lifters.

10. If necessary, replace the valve guide bushings:
1. Using the SA9126E-1 driver and a hammer, drive out the valve guide bushing.




2. Using a SA91102NE or equivalent, measure the bushing bore diameter in the cylinder head. If the bushing bore diameter of the cylinder head is more than 11.368 mm (0.4475 in), use the SA9126E-5 large reamer and ream the bore to 11.587-11.613 mm (0.456-0.457 in) to install an oversized bushing. If the bushing bore diameter of the cylinder head exceeds 11.613 mm (0.457 in), replace the cylinder head.
Specifications
Cylinder Head Valve Guide Bore (Cold)
• Standard: 11.337-11.363 mm (0.446-0.447 in)
• Service Limit: 11.368 mm (0.4475 in) max.
Specifications

Oversize Bore: 11.587-11.613 mm (0.456-0.457 in)






Important

Do not oil or use any thread locking materials when installing the valve guides.

3. Using a SA9126E1 and E2 and a hammer, drive in a new valve guide bushing.
Specifications

Guide Height above Cylinder Head Valve Spring Seat: 10.25-10.5 mm (0.4035-0.4133 in)









Important

Two special reamers are required to ream the guide. Oil the reamer with SAE 5W30 SG engine or cutting oil. Slowly drive the small reamer through the valve guide bore with a 1/2 HP drill motor set at 500 RPM. Check the valve guide bore to valve stem clearance first. If required, slowly drive the second, larger, reamer through the guide to obtain the specified clearance.

Important

Make sure the reamer flutes are clean prior to reaming each guide.

4. Using the 2 sharp reamers SA9126E2-E4 , ream the valve guide bushing to obtain the specified clearance between the valve guide bushing and the new valve stem.
Specification
Clearance
• Intake Standard: 0.025-0.064 mm (0.001-0.0025 in)
• Intake Service Limit: 0.113 mm (0.0044 in) max.
• Exhaust Standard: 0.037-0.082 mm (0.0015-0.0032 in)
• Exhaust Service Limit: 0.131 mm (0.005 in) max.




11. Inspect and grind the valves:

Important

If the valve head is cupped, it must be replaced.

1. Grind the valve only enough to remove the pits and carbon.




2. Check that the valve is ground to the correct valve face angle.
Specifications

Valve Face Angle Intake and Exhaust Standard: 44.5-45 degrees.





3. Check the valve head margin thickness. If the valve head margin thickness is less than minimum, replace the valve.
Specifications
Margin Thickness
• Intake Service Limit: 0.75 mm (0.0295 in) min.
• Exhaust Service Limit: 0.75 mm (0.0295 in) min.




4. Check the valve overall length. If the valve overall length is less than minimum, replace the valve.
Specifications
Minimum Overall Length
• Intake Standard: 100.72-101.18 mm (3.9654-3.9835 in)
• Intake Service Limit: 100.64-101.26 mm (3.962-3.987 )
• Exhaust Standard: 100.02-100.48 mm (3.9378-3.956 in)
• Exhaust Service Limit: 99.94-100.56 mm (3.935-3.959 in)





Important

Do not grind off more than the minimum overall length.

5. Check the surface of the valve stem tip for damage. If the valve stem tip is damaged, grind the valve stem tip with a grinder until flat. Replace the valve if necessary.





Important

Valve seats are released for service and can be replaced. Damaged seats are usually replaced by a machine shop.

12. Inspect and clean the valve seats.
Specifications
Cylinder Head Dimensions
• Intake Valve Seat Bore Standard: 33.399-33.423 mm (1.315-1.316 in)
• Exhaust Valve Seat Bore Standard: 28.399-28.423 mm (1.118-1.119 in)
Specifications
Valve Seat Outside Diameter
• Intake Standard: 33.49-33.51 mm (0.318-0.319 in)
• Exhaust Standard: 28.49-28.51 mm (1.121-1.122 in)




1. Using a 44.5-45 degree carbide cutter or stone, resurface the valve seats. Remove only enough metal to clean the seats. Check the valve seat width:
Specifications
Valve Seat Width
• Intake Standard: 0.79-1.23 mm (0.031-0.048 in)
• Intake Service Limit: 1.66 mm (0.0653 in) max.
• Exhaust Standard: 1.05-1.49 mm (0.041-0.058 in)
• Exhaust Service Limit: 1.92 mm (0.0756 in) max.




2. Check the valve seating position. Apply a thin coat of Prussian blue, or white lead, to the valve face. Install the valve. While applying light pressure to the valve, rotate the valve against the seat.




3. Check the valve face and seat for the following:
• If blue appears 360 degrees around the face, the valve is concentric. If not, replace the valve.
• If blue appears 360 degrees around the valve seat, the guide and seat are concentric. If not, resurface the seat.
• Check that the seat contact is on the middle of the valve face. If not, correct the valve seat as follows:
• 
  
  
  If the seating is too high on the valve face, use 30 degree and 45 degree cutters or stone to correct the seat width.
• 
  
  
  If the seating is too low on the valve face, use 60 degree and 45 degree cutter or stone to correct the seat.




4. Hand-lap the valve and valve seat with an abrasive compound.
5. Clean the valve and valve seat after lapping using solvent.




6. Install the valve without the seal and measure the tip height with calipers.
Specifications
Maximum Height Dimensions
• Standard: 40.95-41.55 mm (1.612-1.636 in)
• Service Limit: 40.95 mm (1.612 in) min Service Limit: 41.6 mm (1.638 in) max.




13. Inspect the valve springs:
1. Using a ruler, measure the height of the valve spring at 4 locations. If the valve spring is bent, replace it.
Specifications
Maximum Squareness
• Standard: 2 mm (0.08 in) max.
• Service Limit: 2.5 mm (0.1 in) max.




2. Using calipers or a SA9179NE or equivalent, measure the free length of the valve spring. If the free length is not within specification, replace the valve spring.
Specifications

Free Length Standard: 41.8 mm (1.65 in) min.





3. Using a SA9183NE spring tester or equivalent, fully collapse the spring 3 times, then measure the tension of the valve spring at the specified installed length. If the installed tension is not as specified, replace the valve spring.
Specifications
Tension at 26.25 mm (1.033 in)
• Standard: 724-788 N (163-177 lbs)
• Service Limit: 688 N (155 lbs) min.
Specifications
Tension at 35.25 m (1.388 in)
• Standard: 293-329 N (66-74 lbs)
• Service Limit: 278 N (63 lbs) min.




14. Check the hydraulic lifter diameter and cylinder head bore for wear.
Specifications
• Lifter Diameter Standard: 32.959-32.975 mm (1.2976-1.2982 in)
• Lifter Diameter Service Limit: 32.947 mm (1.297 in) min.
• Cylinder Head Bore Diameter Standard: 33-33.025 mm (1.2992-1.3002 in)
• Cylinder Head Bore Diameter Service Limit: 33.03 mm (1.3004 in) max.
• Oil Clearance Standard: 0.025-0.066 mm (0.001-0.0026 in)
• Oil Clearance Service Limit: 0.083 mm (0.003 in) max.





Important

Lifters must be installed in the same bores. Lifters are very difficult to repair and must be replaced as an assembly.

Important

A welded joint exists 2 mm (0.08 in) from the bottom of the lifter, contact surface with the camshaft lobe. The 0.2 mm (0.008 in) maximum wide weld mark must not be mistaken for a crack.

15. Inspect and clean the lifters externally.




16. Inspect the intake and exhaust manifolds. Using a precision straight edge and feeler gage, measure the surfaces contacting the head, intake manifold, and exhaust manifold for warpage. If warpage is greater than maximum, replace the manifold.
Specifications
Warpage
• Intake Manifold-to-Cylinder Head Standard: 0.13 mm (0.0051 in) max.
• Intake Manifold-to-Cylinder Head Service Limit: 0.2 mm (0.008 in) max.
• Exhaust Manifold-to-Cylinder Head Standard: 0.25 mm (0.01 in) max.
• Exhaust Manifold-to-Cylinder Head Service Limit: 0.35 mm (0.014 in) max.
• Intake Manifold-to-Throttle Body Standard: 0.1 mm (0.004 in) max.
• Intake Manifold-to-Throttle Body Service Limit: 0.15 mm (0.006 in) max.
• Exhaust Manifold-to-Front Exhaust Pipe Flange Standard: 0.4 mm (0.0016 in) max.
• Exhaust Manifold-to-Front Exhaust Pipe Flange Service Limit: 0.4 mm (0.0016 in) max.
• Intake Manifold EGR Flange Standard: 0.1 mm (0.004 in) max.
• Intake Manifold EGR Flange Service Limit: 0.15 mm (0.006 in) max.