Cylinder Head Assembly: Testing and Inspection
CYLINDER HEAD1. Inspect cylinder head for damage, cracks, and leakage of oil and water. Replace cylinder head if necessary.
2. Measure cylinder head mating surface in six directions as shown in figure.
Distortion: 0.004 inch(0.10 mm) maximum
NOTICE: Before resurfacing head, check following and repair or replace cylinder head if necessary:
a. Sunken valve seats
b. Damage at intake and exhaust manifold mating surfaces
c. Camshaft oil clearances and end play
3. Grind cylinder head mating surface if distortion exceeds specification.
Distortion: 0.004 inch (0.10 mm) maximum
4. Check cylinder head height by measuring from cylinder deck surface to cylinder head cover gasket surface.
5. If cylinder head height is not within specification, replace cylinder head.
Height: 5.272 - 5.28 inch (133.9 - 134.1 mm)
6. Measure intake and exhaust manifold mating surface distortion at two directions shown in figure.
Distortion: 0.008 inch (0.20 mm) maximum
7. If distortion exceeds specification, resurface or replace cylinder head.
Distortion: 0.008 inch (0.20 mm) maximum
VALVE MECHANISM
1. Inspect each valve for following:
a. Damaged or bent valve stem
b. Rough or damaged face
c. Damaged or unevenly worn stem tip
2. Resurface or replace valve as needed.
Margin thickness:
Intake: 0.472 inch (1.2 mm)
Exhaust: 0.472 inch (1.2 mm)
3. Measure length of each valve.
Length:
Intake: 4.052 inch (102.92 mm)
Exhaust: 3.993 inch (101.42 mm)
4. Measure diameter of each valve stem.
Diameter:
Intake: 0.2350 - 0.2356 inch (5.970 - 5.985 mm)
Exhaust: 0.2348 - 0.2354 inch (5.965 - 5.980 mm)
5. Measure inside diameter of each valve guide at points shown in figure.
Diameter intake and exhaust valve guide: 0.2367 - 0.2374 inch .01 - 6.03 mm)
6. Calculate valve stem-to-valve guide clearance. Subtract outer diameter of valve stem from inside diameter of respective valve guide.
Clearance:
Intake valve: 0.0010 - 0.0023 inch (inch 25 - 0.060 mm)
Exhaust valve: 0.0012 - 0.0025 inch (0.030 - 0.065 mm)
Max: 0.008 inch (0.20 mm)
7. If clearance exceeds specification, replace valve, and/or valve guide.
8. Measure protrusion height of each valve guide.
Replace valve guide as needed.
A: Intake: 0.539 - 0.563 inch (13.7 - 14.3 mm)
B: Exhaust: 0.658 - 0.681 inch (16.7 - 17.3 mm)
NOTICE: Intake and exhaust valve guides are different. Be sure to use correct valve guide.
VALVE SEAT
1. Inspect contact surface of each valve seat and valve face for following:
a. Roughness
b. Damage
c. Pitting
d. Cracks
2. Resurface valve seats with a 45° valve seat cutter. Resurface valve faces as needed.
3. Apply a coat of Dychem blue to valve face and valve seat and allow to dry.
4. Inspect valve seating by pressing valve against seat and rotating valve 360°.
a. If Dychem blue is not removed 360° around valve face, replace valve.
b. If Dychem blue is not removed 360° around valve seat, resurface valve seat.
5. Measure seat contact width.
Width: 0.078 - 1.059 inch (1.98 - 2.69 mm)
6. Check that valve seat contact area is at center of valve face.
a. If valve seating position is too high, correct valve seat with a 63° valve seat cutter, and a 45° cutter.
b. If seating position is too low, correct valve seat with a 0° and a 45° cutter.
7. Complete seat-cutting process by lapping valve to seat using valve-lapping compound.
8. Inspect valve seat for sinking.
- Notice Clean valves thoroughly before reassembly, and insure that all traces of lapping compound have been removed.
9. Check for valve sink by measuring protruding length (Dimension L) of valve stem to lower valve spring seat.
VALVE SPRING
1. Inspect each valve spring for cracks and damage.
2. Measure free length and out-of-square. Replace valve springs as needed.
Free length: 1.84 inch (46.7 mm)
Out-of-square: 0.0638 inch (1.62 mm) maximum
CAMSHAFT
1. Set front and rear camshaft bearing journals on blocks.
2. Position a dial indicator on center bearing journal and zero dial.
3. Rotate camshaft in V-blocks and check runout.
Runout: 0.0012 inch (0.03 mm) maximum
4. Check camshaft for uneven wear patterns, cracks, or damage.
5. Measure cam lobe heights at two points as shown.
Lobe height:
Intake: 1.6415 inch (41.6949 mm)
Exhaust: 1.6629 inch (42.2369 mm)
6. Check camshaft bearing journal diameter (X and Y directions) on both sides (A and B) of journal as shown in figure.
Standard diameter: 1.0606 - 1.0616 inch (26.940 - 26.965 mm)
Minimum diameter: 1.0594 inch (26.910 mm)
Out-of-round: 0.002 inch (0.05 mm) maximum
7. Replace camshafts if necessary.
8. Measure camshaft journal oil clearance with Hydraulic Lash Adjusters (HLA) removed.
9. Remove all foreign material and oil from journals and bearing surfaces.
10. Set camshafts onto cylinder head.
11. Position Plastigage on journals in axial direction.
12. Do not rotate camshafts.
13. Install camshaft caps according to cap number and arrow mark.
14. Install cap bolts. Tighten them in five or six steps in order shown.
Tightening torque: 100 - 125 inch lbs.(11.3 - 14.2 Nm, 1.15 - 1.45 kg-m)
15. Loosen camshaft cap bolts in five or six steps in order shown.
16. Remove camshaft caps.
17. Measure oil clearances.
Oil clearance: 0.0014 - 0.0031 inch (0.035 - 0.081 mm)
Maximum: 0.006 in (0.15 mm)
18. If oil clearance exceeds specification, replace cylinder head.
19. Install camshafts.
20. Place a dial indicator against end of camshaft.
21. Using a prying tool, move camshaft as far forward as possible.
22. Zero dial.
23. Using prying tool, move camshaft as far rearward as possible.
24. Check gauge to determine how much end play is present.
End play: 0.0003 - 0.0004 inch (0.08 - 0.10 mm)
Maximum: 0.008 inch (0.20 mm)
HYDRAULIC LASH ADJUSTER (HLA)
1. Check Hydraulic Lash Adjuster (HLA) face for wear or damage, and replace if necessary.
2. With HLA filled with engine oil, hold (A) and press down on (B) by hand. If (B) moves, replace HLA.
NOTICE: Never attempt to repair or disassemble an HLA.
3. Measure HLA bore diameters (X and Y directions) at two points (A and B) as shown.
Distortion: 1.1812 - 1.1820 inch (30.000 - 30.025 mm)
4. Measure HLA diameters (X and Y directions) at two points (A and B) as shown.
Diameter: 1.1795 - 1.1801 inch (29.959 - 29.975 mm)
5. Calculate clearance between HLA diameter and related HLA bore. Replace HLA and/or cylinder head if necessary.
Clearance: 0.00099 - 0.00259 inch (0.025 - 0.066 mm)
Maximum: 0.0071 inch (0.180 mm)