Cylinder Head Cleaning and Inspection SOHC

Tools Required

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

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

1. Clean top of pistons and top of block:

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

1.2.	Remove all the gasket material from the top of the block using a plastic or wood scraper.

1.3.	Blow carbon and oil from the bolt holes.





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.

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

2. To remove gasket material, use a plastic or wood gasket scraper. Remove all gasket material from the manifold and head surfaces.



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



4. Using a valve guide bushing brush and solvent, clean all the valve guide bushings.
5. Using a soft brush and solvent, thoroughly clean the cylinder head:

5.1.	Intake and exhaust parts

5.2.	Intake and exhaust valve seats




6. Inspect 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 maximum, replace the cylinder head.

CYLINDER BLOCK SIDE

•	Transverse

-	Standard: 0.03 mm (0.0012 in) max

-	Service Limit: 0.05 mm (0.002 in) max

•	Longitudinal

-	Standard: 0.07 mm (0.0028 in) max

-	Service Limit: 0.10 mm (0.004 in) max

EXHAUST MANIFOLD SIDE - LONGITUDINAL

•	Standard: 0.10 mm (0.004 in) max

•	Service Limit: 0.15 mm (0.006 in) max

INTAKE MANIFOLD SIDE - LONGITUDINAL

•	Standard: 0.10 mm (0.004 in) max

•	Service Limit: 0.15 mm (0.006 in) max




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



8. Clean the valves:

8.1.	Using a gasket scraper or wire brush, remove all carbon from the valve head.

8.2.	Using a wire brush, thoroughly clean the valve.





Notice: Small scratches, scores, or scuffs on the valve stem will damage and wear out the valve stem seal. Always lubricate the valve guide and valve stem before installing a new valve stem seal. If a valve stem seal is removed after installation, it must be discarded.

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



10. Using a SA91102NE or equivalent or J 43120 , measure the inside diameter of the valve guide bore. Refer to Valve Guide Identification Measurement for proper Go/No-Go gage usage.

Guide Bushing Inside Diameter

•	Standard: 6.987-7.013 mm (0.275-0.276 in)

•	Service Limit: 7.050 mm (0.278 in) max.

Valve Stem Diameter - Intake

•	Standard: 6.949-6.962 mm (0.2736-0.2741 in)

•	Service Limit: 6.935 mm (0.2730 in) min.

Valve Stem Diameter - Exhaust

•	Standard: 6.931-6.950 mm (0.2729-0.2736 in)

•	Service Limit: 6.915 mm (0.2722 in) min.




11. 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.

Oil Clearance - Intake

•	Standard: 0.025-0.064 mm (0.001-0.0025 in)

•	Service Limit: 0.115 mm (0.0045 in) max.

Oil Clearance - Exhaust

•	Standard: 0.037-0.082 mm (0.0015-0.0032 in)

•	Service Limit: 0.135 mm (0.0053 in) max.




12. If necessary, replace valve guides:
13. Using a SA9126E-A and a hammer, drive out the valve guides.



14. Inspect the bushing bore for scoring. If heavily scored, machine the bore to oversize dimensions to remove scoring.
15. Using a ball gage, measure the guide bore diameter of the cylinder head.

•	If the bore is 11.337-11.368 mm (0.4467-0.4479 in) install standard size valve guides.

•	If the bore diameter of the cylinder head is more than 11.368 mm (0.4478 in), use the large reamer in kitSA9126E-A and machine the bore to the following dimensions to install an oversized bushing 11.587-11.613 mm (0.456-0.457 in).

•	If the bushing bore diameter of the cylinder head exceeds 11.613 mm (0.457 in), replace the cylinder head.

•	Valve Guide Bore (Cold)

•	Standard: 11.337-11.363 mm (0.446-0.447 in)

•	Service Limit: 11.368 mm (0.448 in) max.

•	Oversize Bore

•	Standard: 11.587-11.613 mm (0.456-0.457 in)





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

16. Using the driver in kit SA9126E-A and a hammer, drive in a new valve guide bushing.

Guide Height above Cylinder Head Valve Spring Seat
Standard: 10.25-10.5 mm (0.435-0.4133 in)

17. Using the two sharp reamers from kit SA9126E-A , ream the valve guide bushing to obtain the specified clearance between the valve guide bushing and the new valve stem.




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 first with a 1/2 HP drill motor set at 500 RPM. Check the valve guide bore to valve stem clearance. If required, slowly drive the second (larger) reamer through the guide to obtain the specified clearance.

18. Clean the reamer flutes prior to reaming each guide.

Intake Clearance

•	Standard: 0.025-0.064 mm (0.001-0.0025 in)

•	Service Limit: 0.115 mm

•

ax.

Exhaust Clearance

•	Standard: 0.037-0.082 mm (0.0015-0.002 in)

•	Service Limit: 0.135 mm max.




19. Inspect and grind valves:
20. Grind the valve only enough to remove pits and carbon.




Important:  If the valve head is cupped, replace the valve.

21. Check that the valve is ground to the correct valve face angle.

Valve Face Angle (Intake and Exhaust)
Standard: 44.75-45.25 degrees




22. Check the valve head margin thickness. If the valve head margin thickness is less than minimum, replace the valve.

Valve Head Margin Thickness - Intake

•	Standard: 0.96-1.11 mm (0.0378-0.0496 in)

•	Service Limit: 0.90 mm (0.035 in) min.

Valve Head Margin Thickness - Exhaust

•	Standard: 1.12-1.27 mm (0.0441-0.0559 in)

•	Service Limit: 1 mm (0.039 in) min.




23. Check valve overall length. If the valve overall length is less than minimum, replace the valve.

Overall Valve Length - Intake

•	Standard: 138.58-139.05 mm (5.45-5.47 in)

•	Service Limit: 138.48-139.10 mm (5.4-5.48 in)

Overall Valve Length - Exhaust

•	Standard: 138.73-139.25 mm (5.46-5.48 in)

•	Service Limit: 138.68-139.30 mm (5.46-5.48 in)





Important: Do not grind off more than the minimum overall length.

24. Check the surface of the valve stem tip for wear. If the valve stem tip is worn, grind the valve stem tip with a valve 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.

25. Inspect and clean valve seats.

Cylinder Head Dimensions

•	Intake Valve Seat Bore

•	Standard: 41.487-41.513 mm (1.633-1.634 in)

•	Exhaust Valve Seat Bore

•	Standard: 34.987-35.013 mm (1.377-1.378 in)

Valve Seat Insert Outside Diameter

•	Intake Valve Seat

•	Standard: 41.573-41.599 mm (1.6377-1.638 in)

•	Exhaust Valve Seat

•	Standard: 35.073-35.099 mm (1.381-1.382 in)




26. Using a 45 degree carbide cutter or proper stone, resurface the valve seats. Remove only enough metal to clean the seats. Check the valve seat width:

Cylinder Head Valve Seat Width - Intake Seat

•	Standard: 1-1.3 mm (0.0394-0.0512 in)

•	Service Limit: 1.6 mm (0.063 in) max.

Cylinder Head Valve Seat Width - Exhaust Valve Seat

•	Standard: 1.3-1.6 mm (0.0512-0.063 in)

•	Service Limit: 1.9 mm (0.075 in) max.




27. 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.



28. 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, grind the seat.

•	Check that the seat contact is on the middle of the valve face. If not, correct the valve seat as follows:




29. If the seating is too high on the valve face, use 30 degree and 45 degree cutters or stones to correct the seat width.



30. If the seating is too low on the valve face, use 60 degree and 45 degree cutters or stones to correct the seat.



31. Hand-lap the valve and valve seat with an abrasive compound.
32. Clean the valve and valve seat after hand-lapping using solvent.



33. Install the valve without seal and measure the tip height with calipers.

Maximum Height Dimension

•	Standard: 48.25-48.75 mm (1.9-1.919 in)

•	Service Limit: 48.80 mm (1.921 in) max.




34. Inspect valve springs:
35. Using calipers, measure the height of the valve spring at four locations. If the spring is bent, replace it.

Intake and Exhaust Valve Squareness

•	Standard: 2 mm (0.080 in) max

•	Service Limit: 2.5 mm (0.1 in) max.




36. Using calipers, measure the free length of the valve spring. If the free length is not within specification, replace the valve spring.

Free Length
Standard: 48 mm (1.89 in) min




37. Using a spring tester or equivalent, fully collapse the spring 3 times, then measure the tension of the intake and exhaust valve springs at the specified installed length. If the installed tension is not as specified, replace the valve spring.

Spring Length at 30 mm (1.28 in)

•	Standard: 898-983 N (202-211 lbs)

•	Service Limit: 870 N (196 lbs) min.

Spring Length at 41 mm (1.61 in)

•	Standard: 338-387 N (76-87 lbs)

•	Service Limit: 328 N (75 lbs) min.




38. Inspect rocker arms. Check the contact surface of the valve rocker arm and valve stem end and/or camshaft lobe. If the contact surface is worn excessively, replace the rocker arm.



39. Check the hydraulic lifter roller and cylinder head bore for wear.

Lifter/Body Diameter

•	Standard: 21.387-21.405 mm (0.842-0.8427 in)

•	Service Length: 21.38 mm (0.8417 in) min.

Lifter/Roller Total Length

•	Standard: 52.23-52.57 mm (2.0563-0.20697 in)

•	Service Length: 52.15 mm (2.0531 in) min.

Lifter Head Bore Diameter

•	Standard: 21.422-21.448 mm (0.8434-0.8444 in)

•	Service Length: 21.45 mm (0.8445 in) max.

Lifter Body Oil Clearance

•	Standard: 0.017-0.061 mm (0.0007-0.0024 in)

•	Service Length: 0.7 mm (0.0028 in) max.

Lifter Body Guide Flat

•	Standard: 19.18-19.52 mm (0.7551-0.7598 in)

•	Service Length: 19.385 mm (0.7632 in) max.





Important: Internal lifter parts should not be mixed with other assemblies. Lifters are very difficult assemblies to repair and should be replaced as an assembly when testing equipment is not available.

40. Disassemble and clean lifters:

40.1.

Remove the lifter plunger retainer.

40.2.

Remove the lifter valve, disk and plunger.

40.3.

Clean the lifter parts in solvent and lubricate prior to assembly.

40.4.

Inspect the internal lifter parts for scratches and wear.




41. Inspect intake and exhaust manifolds. Using a SA9177NE and SA91101NE or equivalent, measure the surfaces contacting the cylinder head, intake manifold, exhaust manifold TBI and EGR valves for warpage. If warpage is greater than maximum, replace the manifold.

Intake Manifold-to-Cylinder Head Warpage

•	Standard: 0.13 mm (0.005 in) max.

•	Service Limit: 0.2 mm (0.008 in) max.

EGR Flange Warpage

•	Standard: 0.1 mm (0.004 in) max.

•	Service Limit: 0.15 mm (0.006 in) max.

Exhaust Manifold-to-Cylinder Head Warpage

•	Standard: 0.2 mm (0.008 in) max.

•	Service Limit: 0.35 mm (0.014 in) max.

Exhaust Manifold-to-Front Exhaust Pipe Flange Warpage

•	Standard: 0.4 mm (0.016 in) max.

•	Service Limit: 0.4 mm (0.016 in) max.

Cylinder Head Cleaning and Inspection DOHC

Tools Required

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

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



3. Remove all the gasket material from the top of the block using a plastic or wood scraper.

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

4. Blow 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.

5. Remove gasket material from cylinder head:
6. Using a plastic or wood gasket scraper, remove all 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.

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



8. Using a valve guide bushing brush and solvent, clean all the valve guide bushings.
9. Using a soft brush and solvent, thoroughly clean the cylinder head:

9.1.	Intake and exhaust ports

9.2.	Intake and exhaust valve seats and guides

10. Inspect cylinder head for flatness. Using a precision SA9177NE or equivalent, and a SA91101NE or equivalent, measure the surfaces contacting the cylinder block and manifolds for warpage. If warpage is greater than maximum, replace the cylinder head.

Cylinder Block Side

•	Transverse

-	Standard: 0.03 mm (0.0012 in).

-	Service Limit: 0.05 mm (0.004 in) max.

•	Longitudinal

-	Standard: 0.07 mm (0.0028 in)

-	Service Limit: 0.1 mm (0.004 in) max.

Intake Manifold Side -- Longitudinal

•	Standard: 0.1 mm (0.004 in)

•	Service Limit: 0.15 mm (0.006 in) max.

Exhaust Manifold Side -- Longitudinal

•	Standard: 0.1 mm (0.004 in)

•	Service Limit: 0.15 mm (0.006 in) max.

EGR Flange

•	Standard: 0.1 mm (0.004 in)

•	Service Limit: 0.15 mm (0.006 in) max.




11. Inspect 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.



12. 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.

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



14. The valve guide I.D. can be inspected for proper size by using the J 43481 . The valve guide I.D. must free of carbon deposits. A wire brush and solvents can be used to remove carbon deposits.

Refer to "Valve Guide Identification Measurement" in this section for proper Go/No-Go gage usage.

To calculate oil clearance between the valve stem and valve guide, measure the guide bushing at three locations using a SA91102NE .

Guide Bushing Inside Diameter

•	Standard: 6-6.02 mm (0.2364-0.2372 in)

•	Service Limit: 6.06 mm (0.23 in) max.




15. Using a micrometer, measure the diameter of the valve stem.

Valve Stem Diameter - Intake

•	Standard: 5.958-5.997 mm (0.2347-0.2372 in)

•	Service Limit: 5.945 mm (0.2342 in) min.

Valve Stem Diameter - Exhaust

•	Standard: 5.944-5.963 mm (0.2349 in) min.

•	Service Limit: 5.93 mm (0.2336 in) min.

Oil Clearance - Intake

•	Standard: 0.025-0.064 mm (0.001-0.0025 in)

•	Service Limit: 0.115 mm (0.0044 in) max.

Oil Clearance - Exhaust

•	Standard: 0.037-0.082 mm (0.0015-0.0032 in)

•	Service Limit: 0.131 mm (0.005 in) max.




16. If necessary, replace valve guide bushings:
17. Using theJ 43225 Valve Guide Remover/Installer and a hammer, drive out the valve guide bushing.



18. Using a ball hole gage or aSA91102NE 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 large reamer SA9126E-10 and ream the bore to the following dimensions to install an oversized bushing (11.587-11.613 mm (0.456-0.457 in). If the bushing bore diameter of the cylinder head exceeds 11.613 mm (0.457 in), replace the cylinder head.

Cylinder Head Valve Guide Bore (Cold)

•	Standard: 11.337-11.363 mm (0.446-0.447 in)

•	Service Limited: 11.368 mm (0.4474 in) max.

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





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

19. Using drivers J-43225-3 and a hammer, drive in a new valve guide bushing.

Guide Height Above Cylinder Head Valve
Spring Seat: 8.3-8.55 mm (0.327-0.3369 in).




20. Using drivers J-43225-3 and a hammer, drive in a new valve guide bushing.




Important: Do not use the 1991-1998 model year reamer. This reamer is 7 mm in diameter. The 2000 DOHC valve guide is 6 mm in diameter. Use the correct reamer for 2000-01 DOHC engine SA9126E-10 .

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.
Make sure the reamer flutes are clean prior to reaming each guide.
21. Using a sharp reamer SA9126E-10 , ream the valve guide bushing to obtain the specified clearance between the valve guide bushing and the new valve stem.

Clearance - Intake

•	Standard: 0.025-0.064 mm (0.001-0.0025 in)

•	Service Limit: 0.115 mm (0.0044 in) max

Clearance - Exhaust

•	Standard: 0.037-0.082 mm (0.0015-0.0032 in)

•	Service Limit: 0.131 mm (0.005 in) max




22. Inspect and grind valves:

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

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



24. Check that the valve is ground to the correct valve face angle.

Valve Face Angle: Intake and Exhaust
Standard: 44.5-45°




25. Check the valve head margin thickness. If the valve head margin thickness is less than minimum, replace the valve.

Margin Thickness

•

Intake

•	Service Limit: 0.75 mm (0.0295 in) min.

•

Exhaust

•	Service Limit: 0.75 mm (0.0295 in) min.




26. Check the valve overall length. If the valve overall length is less than minimum, replace the valve.

Minimum Overall Length - Intake

•	Standard: 96.28-96.74 mm (3.7934-3.8116 in)

•	Service Limit: 96.2-96.74 mm (3.787-3.812 in)

Minimum Overall Length - Exhaust

•	Standard: 95.58-96.04 mm (3.7659-3.784 in)

•	Service Limit: 95.5-96.04 mm (3.76-3.784 in)





Important: Do not grind off more than the minimum overall length.

27. 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.

28. Inspect and clean valve seats.

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)

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)




29. 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:

Valve Seat Width - Intake

•	Standard: 0.79-1.23 mm (0.031-0.048 in)

•	Service Limit: 1.66 mm (0.0653 in) max.

Valve Seat Width - Exhaust

•	Standard: 1.055-1.49 mm (0.041-0.058 in)

•	Service Limit: 1.92 mm (0.0756 in) max.




30. 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.
31. 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:




32. If the seating is too high on the valve face, use 30 degrees and 45 degree cutters or stones to correct the seat width.



33. If the seating is too low on the valve face, use 60 degrees and 45 degree cutters or stones to correct the seat.



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



36. Install the valve without seal and measure the tip height with calipers.

Maximum Height Dimension

•	Standard: 39.31-39.98 mm (1.548-1.567 in)

•	Service Limit: 39.31-40.28 mm (1.548-1.586 in)




37. Inspect valve springs:
38. Using a ruler, measure the height of the valve spring at four locations. If the valve spring is bent, replace it.

Maximum Squareness

•	Standard: 2 mm (0.08 in) max.

•	Service Limit: 2.5 mm (0.1 in) max.




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

Free Length
Standard: 40.1 mm (1.58 in) min.

40. Using a 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.




Tension at 21.5 mm (0.847 in)

•	Standard: 440-486 N (99-109 lbs)

•	Service Limit: 420 N (94 lbs) min.

Tension at 31 mm (1.221 in)

•	Standard: 186-214 N (42-48 lbs)

•	Service Limit: 180 N (40 lbs) min.




41. Check the lash adjuster diameter and cylinder head bore for wear.

Lifter Diameter

•	Standard: 11.986-12 mm (0.4722-0.4728 in)

•	Service Limit: 11.98 mm (0.4720 in) min.

Cylinder Head Bore Diameter

•	Standard: 12.008-12.03 mm (0.4371-0.4740 in)

•	Service Limit: 12.04 mm (0.4744 in) max.

Oil Clearance

•	Standard: 0.008-0.044 mm (0.0003-0.0017 in)

•	Service Limit: 0.06 mm (0.0024 in) max.





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

42. Inspect and clean lifters, externally.
43. Inspect exhaust manifold. Using a precision straight edge and feeler gage, measure for warpage. If warpage is greater than maximum, replace the manifold.




Exhaust Manifold-to-Cylinder Head Warpage

•	Standard: 0.25 mm (0.01 in) max

•	Service Limit: 0.35 mm (0.014 in) max

Exhaust Manifold-to-Front Exhaust Pipe Flange

•	Standard: 0.4 mm (0.016 in) max

•	Service Limit: 0.4 mm (0.016 in) max