Cylinder Head Assembly: Testing and Inspection

1. Clean top surfaces of pistons and cylinder 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 surface.

(b) Using a gasket scraper, remove all the gasket material from the cylinder block surface.
(c) Using compressed air, blow carbon and oil from the bolt holes.

WARNING: Protect your eyes when using high-pressure compressed air.

2. Clean cylinder head.
A. Remove Gasket Material.

Using a gasket scraper, remove all the gasket material from the cylinder block contact surface.

CAUTION: Be careful not to scratch the cylinder block contact surface.

B. Clean Combustion Chambers.

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

CAUTION: Be careful not to scratch the cylinder block contact surface.

C. Clean Valve Guide Bushings.

Using a valve guide bushing brush and solvent, clean all the guide bushings.
D. Clean Cylinder Head.

Using a soft brush and solvent, thoroughly clean the cylinder head.
3. Inspect cylinder head.
A. Inspect For Flatness.

Using a precision straight edge and feeler gauge, measure the surfaces contacting the cylinder block and the manifolds for warpage.
Maximum warpage:
Cylinder block side: 0.05 mm (0.0020 inch)
Manifold side: 0.05 mm (0.0020 inch)
If warpage is greater than maximum, replace the cylinder head.
B. Inspect For Cracks.

Using a dye penetrant, check the combustion chambers, intake ports, exhaust ports and cylinder block surface for cracks.
If cracked, replace the cylinder head.

4. Clean valves.
(a) Using a gasket scraper, chip off any carbon from the valve head.
(b) Using a wire brush, thoroughly clean the valve.
5. Inspect valve stems and guide bushings.

(a) Using a caliper gauge, measure the inside diameter of the guide bushing.
Bushing inside diameter: 6.010 - 6.030 mm (0.2366 - 0.2374 inch)

(b) Using a micrometer, measure the diameter of the valve stem.
Valve stem diameter:
Intake: 5.970 - 5.985 mm (0.2350 - 0.2356 inch)
Exhaust: 5.865 - 5.980 mm (0.2348 - 0.2354 inch)
(c) Subtract the valve stem diameter measurement from the guide bushing inside diameter measurement.
Standard oil clearance:
Intake: 0.025 - 0.060 mm (0.0010 - 0.0024 inch)
Exhaust: 0.030 - 0.065 mm (0.0012 - 0.0026 inch)
Maximum oil clearance:
Intake: 0.08 mm (0.0031 inch)
Exhaust: 0.10 mm (0.0039 inch)
If the clearance is greater than maximum, replace the valve and guide bushing.
6. If necessary, replace valve guide bushings.

(a) Using Special Service Tool (SST) or equivalent and a hammer, tap out the guide bushing.
SST 09201 - 10000 (09201 - 01060), 09550 - 10012 (09252- 10010)

(b) Using a caliper gauge, measure the bushing bore diameter of the cylinder head.

(c) Select a new guide bushing (STD size or O/S 0.05).
If the bushing bore diameter of the cylinder head is greater than 11.027 mm (0.4341 inch), machine the bushing bore to the following dimension: 11.050 - 11.077 mm (0.4350 - 0.4361 inch).
If the bushing bore diameter of the cylinder head is greater than 11.077 mm (0.4361 inch), replace the cylinder head.

(d) Using SST and a hammer, tap in a new guide bushing to where there is 12.7 - 13.1 mm (0.500 - 0.510 inch) left protruding from the cylinder head.
SST 09201 - 10000 (09201 - 01060), 09550 - 10012 (09252 - 10010) or equivalent.

NOTE: Different bushings are used for the intake and exhaust.

(e) Using a sharp 6 mm reamer, ream the guide bushing to obtain the standard specified clearance (See step 5 above) between the guide bushing and valve stem.
7. Inspect and grind valves.

(a) Grind the valve enough to remove pits and carbon.
(b) Check that the valve is ground to the correct valve face angle.
Valve face angle: 44.5°

(c) Check the valve head margin thickness.
Standard margin thickness: 0.8 - 1.2 mm (0.031 - 0.047 inch)
Minimum margin thickness: 0.5 mm (0.020 inch)
If the margin thickness is less than minimum, replace the valve.

(d) Check the valve overall length
Standard overall length:
Intake: 93.45 mm (3.6791 inch)
Exhaust: 93.69 mm (3.6768 inch)
Minimum overall length:
Intake: 92.95 mm (3.6594 inch)
Exhaust: 93.39 mm (3.6768 inch)
If the overall length is less than minimum, replace the valve.

(e) Check the surface of the valve stem tip for wear.
If the valve stem tip is worn, resurface the tip with a grinder or replace the valve.

CAUTION: Do not grind off more than minimum.

8. Inspect and clean valve seats.

(a) Using a 45 degree carbide cutter, resurface the valve seats. Remove only enough metal to clean the seats.

(b) Check the valve seating position.
Apply a light coat of prussian blue (or white lead) to the valve face. Lightly press the valve against the seat. Do not rotate valve.
(c) Check the valve face and seat for the following:
^ If blue appears 360 degree around the face, the valve is concentric. If not, replace the valve.
^ If blue appears 360 degree around the valve seat, the guide and face are concentric. If not, resurface the seat.
^ Check that the seat contact is in the middle of the valve face with the following width: 1.0 - 1.4 mm (0.039 - 0.055 inch)
If not, correct the valve seats as follows:

(1) If the seating is too high on the valve face, use 30 degree and 45 degree cutters to correct the seat.

(2) if the seating is too low on the valve face, use 75 degree, 60 degree (IN only) and 45 degree cutters to correct the seat.

(d) Hand-lap the valve and valve seat with an abrasive compound.
(e) After hand-lapping, clean the valve and valve seat.
9. Inspect valve springs.

(a) Using a steel square, measure the deviation of the valve spring.
Maximum deviation: 2.0 mm (0.079 inch)
If the deviation is greater than maximum, replace the valve spring.

(b) Using a vernier caliper, measure the free length of the valve spring.
Free length: 53.58 mm (2.1094 inch)
If the free length is not as specified, replace the valve spring.

(c) Using a spring tester, measure the tension of the valve spring at the specified installed length.
Installed tension: 148 - 164 N (15.1 - 16.7 kg, 33.3 - 36.8 lbs.) at 31.8 mm (1.252 inch)
If the installed tension is not as specified, replace the valve spring.
10. Inspect camshafts and bearings.

A. Inspect Camshaft For Runout.
(a) Place the camshaft on V-blocks.
(b) Using a dial indicator, measure the circle runout at the center journal.
Maximum circle runout: 0.04 mm (0.0016 inch)
If the circle runout is greater than maximum, replace the camshaft.

B. Inspect Cam Lobes.
Using a micrometer, measure the cam lobe height.
Standard cam lobe height:
Intake: 41.514 - 41.614 mm (1.6344 - 1.6383 inch)
Exhaust: 41.011 - 41.111 mm (1.61 46 - 1.6185 inch)
Minimum cam lobe height:
Intake: 41.35 mm (1.6279 inch)
Exhaust: 40.85 mm (1.6083 inch)
If the cam lobe height is less than minimum, replace the camshaft.

C. Inspect Camshaft Journals.
Using a micrometer, measure the journal diameter.
Journal diameter:
Exhaust No. 1: 24.949 - 24.965 mm (0.9822 - 0.9829 inch)
Others: 22.949 - 22.965 mm (0.9035 - 0.9041 inch)
If the journal diameter is not as specified, check the oil clearance.

D. Inspect Camshaft Bearings.
Check that bearings for flaking and scoring.
If the bearings are damaged, replace the bearing caps and cylinder head as a set.

E. Inspect Camshaft Gear Spring.
Using a vernier caliper, measure the free distance between the spring ends.
Free distance: 22.5 - 22.9 mm (0.886 - 0.902 inch)
If the free distance is not as specified, replace the gear spring.
F. Inspect Camshaft Journal Oil Clearance.
(a) Clean the bearing caps and camshaft journals.
(b) Place the camshafts on the cylinder head.

(d) Install the bearing caps.
Torque: 13 N.m (130 kg.cm, 9 ft. lbs.)

CAUTION: Do not turn the camshaft.

(e) Remove the bearing caps.

(f) Measure the Plastigage at its widest point.
Standard oil clearance: 0.035 - 0.072 mm (0.0014 - 0.0028 inch)
Maximum oil clearance: 0.10 mm (0.0039 in.)
If the oil clearance is greater than maximum, replace the camshaft. If necessary, replace the bearing caps and cylinder head as a set. Completely remove the Plastigage.
G. Inspect camshaft thrust clearance
(a) Install the camshaft.

(b) Using a dial indicator, measure the thrust clearance while moving the camshaft back and forth.
Standard thrust clearance: 0.045 - 0.100 mm (0.0018 - 0.0039 inch)
Maximum thrust clearance: 0.12 mm (0.0047 inch)
If the thrust clearance is greater than maximum, replace the camshaft. If necessary, replace the bearing caps and cylinder head as a set.
H. Inspect camshaft gear backlash
(a) Install the camshafts without installing the exhaust cam sub-gear.

(b) Using a dial indicator, measure the backlash.
Standard backlash: 0.020 - 0.200 mm (0.0008 - 0.0079 inch)
Maximum backlash: 0.30 mm (0.0188 inch)
If the backlash is greater than maximum, replace the camshafts.
11. Inspect valve lifters and lifter bores.

(a) Using a caliper gauge, measure the lifter bore diameter of the cylinder head.
Litter bore diameter: 28.000 - 28.021 mm (1.1024 - 1.1032 inch)

(b) Using a micrometer, measure the lifter diameter.
Lifter diameter: 27.975 - 27.985 mm (1.1014 - 1.1018 inch)
(c) Subtract the lifter diameter measurement from the lifter bore diameter measurement.
Standard oil clearance: 0.015 - 0.046 mm (0.0005 - 0.0018 inch)
Maximum oil clearance: 0.10 mm (0.0039 inch)
If the oil clearance is greater than maximum, replace the lifter. If necessary, replace the cylinder head.
12. Inspect intake and exhaust manifolds.

Using a precision straight edge and feeler gauge, measure the surface contacting the cylinder head for warpage.
Maximum warpage:
Intake: 0.1 mm (0.004 inch)
Exhaust: 0.5 mm (0.020 inch)
If warpage is greater than maximum, replace the manifold.
13. If necessary, replace spark plug tube gaskets.

(a) Using a screwdriver, pry off the tube gasket.

(b) Using SST and a hammer, tap in a new tube gasket until the upper edge of the cylinder head cover.
SST 09550 - 10012 (09252 - 10010, 09556 - 10010) or equivalent.
(c) Apply Multipurpose (MP) grease to the gasket lip.