Cleaning and Inspection

CLEAN TOP SURFACES OF PISTONS CYLINDER BLOCK

1. Turn the crankshaft, and bring each piston to top dead center (TDC). Using a suitable gasket scraper, remove carbon from the piston top surface and all gasket material from the cylinder block surface.

2. Using compressed air, blow carbon, oil and gasket material from the bolt holes.
CAUTION: Protect your eyes when using high pressure compressed air.

INSPECT CYLINDER BLOCK SURFACE FOR FLATNESS

1. Using precision straight edge and feeler gauge as shown in the illustration, measure the top surfaces of the cylinder block for warpage.
Maximum warpage: 0.070 mm (0.0028 inch).

2. If warpage is greater than maximum, replace the cylinder block.

CLEAN CYLINDER HEAD

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

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

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

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

3. Using a valve guide bushing brush and solvent, clean all the guide bushings.

4. Using a soft brush and solvent, thoroughly clean the cylinder head.

INSPECT CYLINDER HEAD

1. Using precision straight edge and feeler gauge, measure the surfaces contacting the cylinder block, intake and exhaust manifolds for warpage.
- Maximum warpage: 0.10 mm (0.0039 inch).
- If warpage is greater than maximum, replace the cylinder head.

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

CLEAN VALVES

1. Using a gasket scraper, chip off any carbon from the valve head.
2. Using a wire brush, thoroughly clean the valve.

INSPECT VALVE STEMS AND GUIDE BUSHINGS

1. Using a valve guide bushing brush and solvent, clean all the guide bushings.

2. 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).

1. 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: 5.965-5.980 mm (0.2348-0.2354 inch).

2. 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).

3. If the clearance is greater than maximum, replace the valve and/or guide bushing.

VALVE GUIDE BUSHING REPLACEMENT

1. Using valve guide driver Special Service Tool (SST) No. 09201-10000 with 09950-70010 and a hammer, tap out the guide bushing.

2. Using a caliper gauge, measure the bushing bore diameter of the cylinder head.

3. Select a new guide bushing (STD or O/S 0.05).

NOTE:
^ If the bushing bore diameter of the cylinder head is greater than 11.006 mm (0.4333 inch), machine the bushing bore to the following dimension: 11.035-11.056 mm (0.4344-0.4353 inch).
^ If the bushing bore diameter of the cylinder hear greater than 11.056 mm (0.4353 inch), replace the cylinder head.

4. Using SST valve guide driver and a hammer, tap in a new guide bushing to the specified protrusion height.
- Protrusion height:
- Intake: 12.3-12.7 mm (0.484-0.500 inch).
- Exhaust: 11.4-11.8 mm (0.449-0.465 inch).

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

5. Using a sharp 6 mm reamer, ream the guide bushing to obtain the standard specified oil clearance between the guide bushing and valve stem.

INSPECT AND GRIND VALVES

1. Check that the valve is ground to the correct valve face angle.
- Valve face angle: 44.50°

2. Check the valve head margin thickness.
- Standard margin thickness: 0.8-1.2 mm (0.0310-O.O470 inch).
- Minimum margin thickness: 0.5 mm (0.0200 inch).
- If the margin thickness is less than minimum, replace the valve.

3. Check the valve overall length.
- Standard overall length:
- Intake: 98.29-98.79 mm (3.8697-3.8894 inch).
- Exhaust: 98.84-99.34 mm (3.8913-3.9110 inch).
- Minimum overall length:
- Intake: 98.19 mm (3.8657 inch).
- Exhaust: 98.74 mm (3.8874 inch).
- If the overall length is less than minimum, replace the valve.

4. 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.

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

INSPECT AND CLEAN VALVE SEATS

1. Using a 45° carbide cutter, resurface the valve seats. Remove only enough metal to clean the seats.
2. Check the valve seating position as follows:

(a) Apply a thin coat of prussian blue (or white lead) to the valve face.
(b) Lightly press the valve against the seat.

NOTE: Do not rotate the valve.

(c) Check the valve face and seat for the following:
- If blue appears 360° around the face, the valve is concentric.
- If not, replace the valve.
- If blue appears 360° around the valve seat, the guide and face are concentric.
- If not, resurface the seat.
(d) Check that the seat contact is in the middle of the valve face with the following width:
- Intake: 1.0-1.4 mm (0.0390-0.0550 inch).
- Exhaust: 1.2-1.6 mm (0.0470-0.0630 inch).
(e) If not, correct the valve seats as follows:

- If the seating is too high on the valve face, use 15° and 45° cutters to correct the seat.

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

3. Hand-lap the valve and valve seat with an abrasive compound.
- After hand-lapping, clean the valve and valve seat.

INSPECT VALVE SPRINGS

1. Using a steel square, measure the deviation of the valve spring.
Maximum deviation: 2.0 mm (0.079 inch).

NOTE: If deviation is greater than maximum, replace the valve spring.

2. Using vernier calipers, measure the free length of the valve spring.
Free length: 41.70 mm (1.6417 inch).

NOTE: If the free length is not as specified, replace the valve spring.

3. Using a spring tester, measure the tension of the valve spring at the specified installed length.
Installed tension: 186-206 N (19.0-21.0 kg. cm., 42-46 ft. lbs.) at 34.5 mm (1.358 inch).

NOTE: If the installed tension is not as specified, replace the valve spring.

INSPECT CAMSHAFTS BEARINGS

Camshaft Runout

1. Place the camshaft on V-blocks.

2. Using a dial indicator, measure the circle runout at the center journal.
- Maximum circle runout: 0.08 mm (0.0031 inch).

NOTE: If the circle runout is greater than maximum, replace the camshaft.

Cam Lobes

1. Using a micrometer, measure the cam lobe height.
- Standard cam lobe height:
Intake: 44.570-44.670 mm (1.7547-1.7587 inch).
Exhaust: 44.770-44.870 mm (1.7626-1.7665 inch).
- Minimum cam lobe height:
Intake: 44.42 mm (1.7488 inch).
Exhaust: 44.62 mm (1.7567 inch).

NOTE: If the cam lobe height is less than minimum, replace the camshaft.

Camshaft Journals

1. Using a micrometer, measure the journal diameter.
- Journal diameter: 28.949-28.965 mm (1.1397-1.1404 inch).

NOTE: If the journal diameter is not as specified, check the oil clearance.

Camshaft Bearings

1. Inspect camshaft bearings for flaking and scoring.

NOTE: If the bearings are damaged, replace the bearing cap and cylinder head as a set.

2. Inspect camshaft journal oil clearance as follows:
(a) Clean the bearing caps and camshaft journal.
(b) Place the camshafts on the cylinder head.

(d) Install the bearing caps and tighten to 20 Nm (200 kg. cm., 14 ft. lbs.) in sequence shown in the illustration.

NOTE: 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 inch).

NOTE:
^ If the oil clearance is greater than maximum, replace the camshaft.
^ If necessary, replace the bearing caps and cylinder head as a set.

(g) Completely remove the Plastigage.

Camshaft Thrust Clearance

1. Install the camshafts as described above.

2. Using a dial indicator, measure the thrust clearance while moving the camshaft back and forth.
Standard thrust clearance: 0.080-0.190 mm (0.0031-0.0075 inch).
Maximum thrust clearance: 0.30 mm (0.0118 inch).

NOTE:
^ If the thrust clearance is greater than maximum, replace the camshaft.
^ If necessary, replace the bearing caps and cylinder head as a set.

INSPECT VALVE LIFTER BORES

1. Using a caliper gauge, measure the lifter bore diameter of the cylinder head.
Lifter bore diameter:31.000-31.016 mm (1.2205-1.2211 inch).

2. Using a micrometer, measure the lifter diameter.
Lifter diameter: 30.966-30.976 mm (1.2191 1.2195 inch).

3. Subtract the lifter diameter measurement from the lifter bore diameter measurement.
Standard oil clearance: 0.024-0.050 mm (0.0009-0.0020 inch).
Maximum oil clearance: 0.07 mm (0.0028 inch).

4. If the oil clearance is greater than maximum, replace the lifter. If necessary, replace the cylinder head.

INSPECT AIR INTAKE CHAMBER

1. Using a precision straight edge and feeler gauge, measure the surfaces contacting the intake manifold for warpage.
- Maximum warpage: 0.15 mm (0.0059 inch).
- If warpage is greater than maximum, replace the chamber.

INSPECT INTAKE MANIFOLD

1. Using a precision straight edge and feeler gauge, measure the surfaces contacting the cylinder head and air intake chamber for warpage.
- Maximum warpage: 0.15 mm (0.0059 inch).
- If warpage is greater than maximum, replace the manifold.

INSPECT EXHAUST MANIFOLDS

1. Using a precision straight edge and feeler gauge, measure the surfaces contacting the cylinder head for warpage.
- Maximum warpage, 0.50 mm (0.0196 inch).
- If warpage is greater than maximum, replace the manifold.

INSPECT CYLINDER HEAD BOLTS

1. Using a vernier caliper, measure the thread outside diameter of the bolt.
- Standard outside diameter: 10.8-11.0 mm (0.425-0.433 inch).
- Minimum outside diameter: 10.7 mm (0.421 inch).
- If the diameter is less than minimum, replace the bolt