Cylinder Head Cleaning and Inspection
- Tools Required
- J43120 Valve Guide Go/No-Go Gauge
- SA9126E-A Valve Guide Seat Set
- SA9199NE Straight Edge
- SA9llOlNE Feeler Gauge Set
1. Clean top of pistons and top of block:
a. Turn the crankshaft and bring each piston to Top Dead Center (TDC). Using a gasket scraper, remove all the carbon from the piston top.
IMPORTANT: Cover front of engine with a shop towel to prevent debris from entering the oil gallery opening and pan.
b. Remove all the gasket material from the top of the block using a plastic or wood scraper.
CAUTION: PROTECT YOUR EYES WHEN USING HIGH PRESSURE AIR.
c. 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.
- Be careful not to scratch the aluminum surfaces when cleaning the cylinder head.
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:
a. Intake and exhaust parts.
b. Intake and exhaust valve seats.
6. Inspect cylinder head for flatness. Using a precision straight edge SA9177NE (or equivalent) and feeler gauge SA 91101NE (or equivalent), measure the surfaces contacting the cylinder block and manifolds for warpage. If warpage is greater than maximum, replace the cylinder head.
MAXIMUM WARPAGE SPECIFICATIONS:
Cylinder Block Side:
Transverse:
Standard: 0.03 mm (0.0012 inch) max.
Service Limit: 0.05 mm (0.002 inch) max.
Longitudinal:
Standard: 0.07 mm (0.0028 inch) max.
Service Limit: 0.10 mm (0.004 inch) max.
Exhaust Manifold Side: Longitudinal: Standard: 0.10 mm (0.004 inch) max. Service Limit: 0.15 mm (0.006 inch) max.
Intake Manifold Side: Longitudinal: Standard: 0.10 mm (0.004 inch) max. Service Limit: 0.15 mm (0.006 inch) 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:
a. Using a gasket scraper or wire brush, remove all carbon from the valve head.
b. Using a wire brush, thoroughly clean the valve.
9. Inspect valve stems and guides for wear, scratches, and burrs:
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.
8. Using a ball gauge SA91102NE (or equivalent) or Go/No-Go gauge P/N J43120, measure the inside diameter of the valve guide bore. Refer to "Valve Guide Identification Measurement" in the "Engine Diagnostic" for proper Go/No-Go gauge usage.
Guide Bushing Inside Diameter:
Standard: 6.987 - 7.013 mm (0.275 - 0.276 inch)
Service Limit: 7.050 mm (0.278 inch) max.
b. Using a micrometer, measure the diameter of the valve stem.
Valve Stem Diameter:
Intake:
Standard: 6.949 - 6.962 mm (0.2736 - 0.2741 inch)
Service Limit: 6.935 mm (0.2730 inch) min.
Exhaust:
Standard: 6.931 - 6.950 mm (0.2729 - 0.2736 inch)
Service Limit: 6.915 mm (0.2722 inch) min.
c. 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 inch)
Service Limit: 0.115 mm (0.0045 inch) max.
Exhaust:
Standard: 0.037 - 0.082 mm (0.0015 - 0.0032 inch)
Service Limit: 0.135 mm (0.0053 inch) max.
10. If necessary, replace valve guides:
a. Using service tool SA9126E and a hammer, drive out the valve guide(s).
b. Inspect the bushing bore for scoring. If heavily scored, machine the bore to oversize dimensions to remove scoring.
c. Using a ball gauge, measure the guide bore diameter of the cylinder head. If the bore is 11.337 - 11.368 mm (0.4467 - 0.4479 inch) install standard size valve guides.
d. If the bore diameter of the cylinder head is more than 11.368 mm (0.4478 inch), use the large reamer in kit SA8126E and machine the bore to the following dimensions to install an oversized bushing (11.587 - 11.613 mm [0.456 - 0.457 inch]). If the bushing bore diameter of the cylinder head exceeds 11.613 mm (0.457 inch), replace the cylinder head.
Valve Guide Bore (Cold):
Standard: 11.337 - 11.363 mm (0.446 - 0.447 inch)
Service Limit: 11.368 mm (0.448 inch) max.
Oversize Bore:
Standard: 11.587 - 11.613 mm (0.456 - 0.457 inch)
e. Using the driver in kit SA9126E and a hammer, drive in a new valve guide bushing.
Guide Height above Cylinder Head Valve Spring Seat:
Standard: 10.25 - 10.5 mm (0.4035 - 0.4133 inch)
IMPORTANT: Do not oil or use any thread locking materials when installing valve guides.
f. Using the two sharp reamers from kit SA9126E, 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 SW30 SO 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.
- Make sure the reamer flutes are clean prior to reaming each guide.
Intake Clearance:
Standard: 0.025-0.064 mm ( 0.001-0.0025 inch
Service Limit: 0.115 mm (0.0045) max.
Exhaust Clearance:
Standard: (0.037 - 0.082 mm (0.0015 - 0.002 inch)
Service Limit: 0.135 mm (0.0053) max.
11. Inspect and grind valves:
a. Grind the valve only enough to remove pits and carbon.
IMPORTANT: If the valve head is cupped, replace the valve.
b. Check that the valve is ground to the correct valve face angle.
Valve Face Angle (Intake and Exhaust):
Standard: 44.75 - 45.25 degrees
c. Check the valve head margin thickness. If the valve head margin thickness is less than minimum, replace the valve.
Intake:
Standard: 0.96 - 1.11 mm (0.0378 - 0.0496 inch)
Service Limit: 0.90 mm (0.035 inch) min.
Exhaust:
Standard: 1.12 - 1.27 mm (0.0441 - 0.0559 inch)
Service Limit: 1.00 mm (0.039 inch) min.
d. Check valve overall length. If the valve overall length is less than minimum, replace the valve.
Overall Valve Length:
Intake:
Standard: 138.53 - 139.05 mm (5.45 - 5.47 inch)
Service Limit: 138.48 - 139.10 mm (5.4 - 5.48 inch)
Exhaust:
Standard: 138.73 - 139.25 mm (5.46 - 5.48 inch)
Service Limit: 138.68 - 139.30 mm (5.46 - 5.48 inch)
NOTICE: Do not grind of f more than the minimum overall length.
e. 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.
12. Inspect and clean valve seats.
IMPORTANT: Valve seats are released for service and can be replaced. Damaged seats are usually replaced by a machine shop.
Cylinder Head Dimensions:
Intake Valve Seat Bore:
Standard: 41.487 - 41.513 mm (1.633 - 1.634 inch)
Exhaust Valve Seat Bore:
Standard: 34.987 - 35.013 mm (1.377 - 1.378 inch)
Valve Seat Insert Out Diameter:
Intake Valve Seat:
Standard: 41.573 - 41.599 mm (1.6377 - 1.638 inch)
Exhaust Valve Seat:
Standard: 35.073 - 35.099 mm (1.381 - 1.382 inch)
a. 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 Width:
Standard: 1.0 - 1.3 mm (0.0394 - 0.0512 inch)
Service Limit: 1.6 mm (0.063 inch) max.
Exhaust Valve Seat:
Standard: 1.3 - 1.6 mm (0.0512 -0.0630 inch)
Service Limit: 1.9 mm (0.075 inch) max.
b. 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.
c. 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:
- 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.
d. Hand-lap the valve and valve seat with an abrasive compound.
e. Clean the valve and valve seat after hand-lapping using solvent.
f. Install the valve without seal and measure the tip height with calipers.
Maximum Height Dimension:
Standard: 48.25 - 48.75 mm (1.900 - 1.919 inch)
Service Limit: 48.80 mm (1.921 inch) max.
13. Inspect valve springs:
a. 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: 2.0 mm (0.080 inch)max.
Service Limit: 2.5 mm (0.100 inch) max.
b. 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: 48.00 mm (1.89 inch) min.
c. Using a spring tester SA9183NE (or equivalent), fully collapse the spring three 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.
Dim. A at 30.0 (1.28):
Standard: 898 - 983 N (202 - 211 lbs.)
Service Limit: 870 N (196 lbs.) min.
Dim. B at 41.0 (1.61):
Standard: 338 - 387 N (76 - 87 lbs.)
Service Limit: 328 N (75 lbs.) min.
14. 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.
15. Check the hydraulic lifter roller and cylinder head bore for wear.
Lifter/Body Diameter:
Standard: 21.387 - 21.405 mm (0.8420 - 0.8427 inch)
Service Limit: 21.380 mm (0.8417 inch) min.
Lifter/Roller Total Length:
Standard: 52.23 - 52.57 mm (2.0563 - 2.0697 inch)
Service Limit: 52.15 mm (2.0531 inch) min.
Cylinder Head Bore Diameter:
Standard: 21.422 - 21.448 mm (0.8434 - 0.8444 inch)
Service Limit: 21.45 mm (0.8445 inch) max.
Lifter Body Oil Clearance:
Standard: 0.017 - 0.061 mm (0.0007 - 0.0024 inch)
Service Limit: 0.07 mm (0.0028 inch) max.
Lifter Body Guide Flat:
Standard: 19.18 - 19.30 mm (0.7551 - 0.7598 inch)
Service Limit: 19.15 mm (0.7539 inch) min.
Lifter Guide Plate Width:
Standard: 19.39 - 19.52 mm (0.7634 - 0.7685 inch)
Service Limit: 19.385 mm (0.7632 inch) max.
NOTICE: 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.
16. Disassemble and clean lifters:
a. Remove the lifter plunger retainer.
b. Remove the lifter valve, disk and plunger.
c. Clean the lifter parts in solvent and lubricate prior to assembly.
d. Inspect the internal lifter parts for scratches and wear.
17. Inspect intake and exhaust manifolds. Using a precision straight edge SA9177NE and feeler gauge SA9llOlNE (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.
Warpage:
Intake Manifold-to-Cylinder Head: Standard: 0.13 mm (0.005 inch) max.
Service Limit: 0.20 mm (0.008 inch) max.
EGR Flange:
Standard: 0.10 mm (0.004 inch) max.
Service Limit: 0.15 mm (0.006 inch) max.
Exhaust Manifold-to-Cylinder Head:
Standard: 0.2 mm (0.008) max.
Service Limit: 0.35 mm (0.014 inch) max.
Exhaust Manifold-to-Front Exhaust Pipe Flange:
Standard: 0.4 mm (0.016 inch) max.
Service Limit: 0.4 mm (0.016 inch) max.