Tools Required

1. Clean the top of the pistons and 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.

1.1.	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.

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

2. Remove the gasket material from the cylinder head.

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.

3. 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.

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



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

•	Intake and exhaust ports

•	Intake and exhaust valve seats and guides




7. 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 maximum, replace the cylinder head.

Specifications

Cylinder Block Side Maximum Warpage

•	Standard Transverse: 0.03 mm (0.0012 in)

•	Service Limit Transverse: 0.05 mm (0.002 in) max.

•	Standard Longitudinal: 0.07 mm (0.0028 in)

•	Service Limit Longitudinal: 0.1 mm (0.004 in) max.

Specifications

Intake Manifold Side Maximum Warpage

•	Standard Longitudinal: 0.1 mm (0.004 in)

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

Specifications

Exhaust Manifold Side Maximum Warpage

•	Standard Longitudinal: 0.1 mm (0.004 in)

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

Specifications

EGR Flange Maximum Warpage

•	Standard: 0.1 mm (0.004 in) max.

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




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



9. 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.

10. Inspect the valve stems and guides for wear, scratches, and burrs.




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

To calculate oil clearance between the valve stem and valve guide, measure the guide bushing at 3 locations using a SA91102NE or equivalent.

Specifications

Guide Bushing Inside Diameter

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

•	Service Limit: 6.06 mm (0.239 in) max.





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

Specifications

Valve Stem Diameter

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

•	Service Limit Intake: 5.945 mm (0.2342 in) max.

•	Standard Exhaust: 5.944-5.963 mm (0.2342-0.2349 in) min.

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

9.3.	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

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

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

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

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




11. If necessary, replace the valve guide bushings.

10.1.

Using the J 43225 and a hammer, drive out the valve guide bushing.





10.2.

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 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.

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.

•	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.

10.3.

Using the J43225-3 and a hammer, drive in a new valve guide bushing.

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





Important: Do not use the 1991-1998 model year reamer. This reamer is 7 mm in diameter. The 1999 DOHC valve guide is 6 mm in diameter. Use the correct reamer for 1999 DOHC engine, SA9126E-10 .

Important: Oil the reamer with SAE 5W-30 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.

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

10.4.

Using a sharp SA9126E-10 , ream the valve guide bushing to obtain the specified clearance between the valve guide bushing and the new valve stem.

Specifications

Clearance

•	Standard Intake: 0.025-0.064 mm (0.00100.0025 in)

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

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

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





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

12. Inspect and grind the valves.

11.1.

Grind the valve only enough to remove pits and carbon.





11.2.

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

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





11.3.

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

Specifications

Margin Thickness

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

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





11.4.

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

Specifications

Minimum Overall Length

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

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

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

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





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

11.5.

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

13. Inspect and clean the valve seats.

Specifications

Cylinder Head Dimensions

•	Standard Intake Valve Seat Bore: 33.399-33.423 mm (1.315-1.316 in)

•	Standard Exhaust Valve Seat Bore: 28.399-28.423 mm (1.118-1.119 in)

Specifications

Valve Seat Outside Diameter

•	Standard Intake: 33.49-33.51 mm (1.318-1.319 in)

•	Standard Exhaust: 28.49-28.51 mm (1.121-1.122 in)





12.1.

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

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

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

•	Standard Exhaust: 1.05-1.49 mm (0.041-0.058 in)

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





12.2.

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.





12.3.

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 stones to correct the seat width.





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





12.4.

Hand-lap the valve and valve seat with an abrasive compound.

12.5.

Clean the valve and valve seat after lapping using solvent.





12.6.

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

Specifications

Maximum Height Dimensions

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

•	Service Limit: 39.31 mm (1.548 in) min.

•	Service Limit: 40.28 mm (1.586 in) max.




14. Inspect the valve springs.

13.1.

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.

13.2.

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

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





13.3.

Using a SA9183NE 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 21.5 mm (0.85 in)

•	Standard: 440-486 N (99-109 lbs)

•	Service Limit: 420 N (94 lbs) min.

Specifications

Tension at 31 mm (1.22 in)

•	Standard: 186-214 N (42-48 lbs)

•	Service Limit: 180 N (40 lbs) min.




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

Specifications

Lifter Diameter

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

•	Service Limit: 11.98 mm (0.472 in) min.

Specifications

Cylinder Head Bore Diameter

•	Standard: 12.008-12.03 mm (0.4371-0.474 in)

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

Specifications

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.

16. Inspect and clean the lifters, externally.



17. Inspect the intake and exhaust manifolds. Using a precision straight edge and feeler gage, measure the surfaces contacting the cylinder head, intake manifold, and exhaust manifold for warpage. If warpage is greater than the maximum, replace the manifold.

Specifications

Intake Manifold-to-Cylinder Head Warpage

•	Standard: 0.13 mm (0.0051 in) max.

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

Specifications

Exhaust Manifold-to-Cylinder Head Warpage

•	Standard: 0.25 mm (0.01 in) max.

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

Specifications

Intake Manifold-to-Throttle Body Warpage

•	Standard: 0.1 mm (0.004 in) max.

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

Specifications

Exhaust Manifold-to-Front Exhaust Pipe Flange

•	Standard: 0.4 mm (0.016 in) max.

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

Specifications

Intake Manifold EGR Flange

•	Standard: 0.1 mm (0.004 in) max.

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