Inspection

Components

CAUTION:
^ When installing camshafts, chain tensioners, oil seals, or other sliding parts, lubricate contacting surfaces with new engine oil.
^ Apply new engine oil to threads and seat surfaces when installing cylinder head, camshaft sprocket, crankshaft pulley, and camshaft bracket.
^ Attach tags to valve lifters so as not to mix them up.

Inspection

CYLINDER HEAD DISTORTION





Clean surface of cylinder head.
Use a reliable straightedge and feeler gauge to check the flatness of cylinder head surface.
Check along six positions shown in the figure.
Head surface flatness: Limit 0.1 mm (0.004 inch)
If beyond the specified limit, resurface or replace it.
The limit for cylinder head resurfacing is determined by the cylinder block resurfacing.
Resurfacing limit:
Amount of cylinder head resurfacing is "A".
Amount of cylinder block resurfacing is "B".
The maximum limit: A + B = 0.2 mm (0.008 inch)
After resurfacing cylinder head, check that camshaft rotates freely by hand. If resistance is felt, cylinder head must be replaced.
Nominal cylinder head height: 126.3 - 126.5 mm (4.972 - 4.980 inch)

CAMSHAFT VISUAL CHECK
Check camshaft for scratches, seizure and wear.

CAMSHAFT RUNOUT
1. Put V block on precise flat bed, and support No. 2 and No. 4 journal of camshaft.





2. Set dial gauge vertically to No. 3 journal.
3. Turn camshaft to one direction with hands, and measure camshaft runout on dial gauge. (Total indicator reading)
Runout (Total indicator reading): Limit 0.05 mm (0.0020 inch)
4. If it exceeds the limit, replace camshaft.

CAMSHAFT CAM HEIGHT





1. Measure camshaft cam height.
Standard cam height:
Intake and exhaust 44.865 - 45.055 mm (1.7763 - 1.7738 inch)
Cam wear limit: 0.2 mm (0.008 inch)
2. If wear is beyond the limit, replace camshaft.

CAMSHAFT JOURNAL CLEARANCE
1. Install camshaft bracket and tighten bolts to the specified torque.





2. Measure inner diameter "A" of camshaft bearing.
Standard inner diameter:
No. 1: 26.000 - 26.021 mm (1.0236 - 1.0244 inch)
No. 2, 3, 4: 23.500 - 23.521 mm (0.9252 - 0.9260 inch)





3. Measure outer diameter of camshaft journal.
Standard outer diameter:
No. 1: 25.935 - 25.955 mm (1.0211 - 1.0218 inch)
No. 2, 3, 4: 23.445 - 23.465 mm (0.9230 - 0.9238 inch)
4. If clearance exceeds the limit, replace camshaft and/or cylinder head.
Camshaft journal clearance:
Standard
No. 1: 0.045 - 0.086 mm (0.0018 - 0.0034 inch)
No. 2, 3, 4: 0.035 - 0.076 mm (0.0014- 0.0030 inch)
Limit 0.15 mm (0.0059 inch)

CAMSHAFT END PLAY
1. Install camshaft in cylinder head.





2. Measure camshaft end play.
Camshaft end play:
Standard 0.115 - 0.188 mm (0.0045 - 0.0074 inch)
Limit 0.24 mm (0.0094 inch)

CAMSHAFT SPROCKET RUNOUT
1. Put V block on precise flat bed, and support No. 2 and No. 4 journal of camshaft.
2. Install sprocket on camshaft.





3. Measure camshaft sprocket runout.
Runout (Total indicator reading): Less than 0.15 mm (0.0059 inch)
4. If it exceeds the limit, replace camshaft sprocket.

VALVE GUIDE CLEARANCE





1. Measure valve deflection as shown in the figure. (Valve and valve guide mostly wear in this direction.)
Valve deflection limit (Dial gauge reading):
Intake 0.24 mm (0.0094 inch)
Exhaust 0.28 mm (0.0110 inch)
2. If it exceeds the limit, check valve to valve guide clearance.





a. Measure valve stem diameter and valve guide inner diameter.
b. Check that clearance is within specification.
Valve to valve guide clearance limit:
Intake 0.08 mm (0.0031 inch)
Exhaust 0.1 mm (0.004 inch)
c. If it exceeds the limit, replace valve or valve guide.

VALVE GUIDE REPLACEMENT





1. To remove valve guide, heat cylinder head to 110 to 130°C (230 to 266°F) by soaking in heated oil.





2. Drive out valve guide with a press [under a 20 kN (2 ton, 2.2 US ton, 2.0 Imp ton) pressure] or hammer and suitable tool.





3. Ream cylinder head valve guide hole.
Valve guide hole diameter (for service parts): 10.175 - 10.196 mm (0.4006 - 0.4014 inch)





4. Heat cylinder head to 110 to 130°C (230 to 266°F) and press service valve guide onto cylinder head.
Projection "L": 12.6 - 12.8 mm (0.496 - 0.504 inch)
5. Ream valve guide.
Finished size: 6.000 - 6.018 mm (0.2362 - 0.2369 inch)

VALVE SEATS





Check valve seats for any evidence of pitting at valve contact surface, and reseat or replace if it has worn out excessively.
^ Before repairing valve seats, check valve and valve guide for wear. If they have worn, replace them. Then correct valve seat.
^ Use both hands to cut uniformly.

REPLACING VALVE SEAT FOR SERVICE PARTS
1. Bore out old seat until it collapses. Boring should not continue beyond the bottom face of the seat recess in cylinder head. Set the machine depth stop to ensure this.





2. Ream cylinder head recess for service valve seat.
Oversize [0.5 mm (0.020 inch)]:
Intake 38.500 - 38.516 mm (1.5157 - 1.5164 inch)
Exhaust 32.700 - 32.716 mm (1.2874 - 1.2880 inch)
Be sure to ream in circles concentric to the valve guide center.
This will enable valve seat to fit correctly.





3. Heat cylinder head to 110 to 130°C (230 to 266°F) by soaking in heated oil.
4. Press fit valve seat until it seats on the bottom.
5. Cut or grind valve seat using suitable tool to the specified dimensions as shown in Specifications.
6. After cutting, lap valve seat with abrasive compound.
7. Check valve seating condition.
Seat face angle "a": 45°15' - 45°45'
Contacting width "W":
Intake 1.09 - 1.31 mm (0.0429 - 0.0516 inch)
Exhaust 1.29 - 1.51 mm (0.0508 - 0.0594 inch)





8. Use a depth gauge to measure the distance between the mounting surface of the cylinder head spring seat and the valve stem end. If the distance is shorter than specified, repeat step 5 above to adjust it. If it is longer, replace the valve seat with a new one.
Valve seat resurface limit "L":
Intake 41.07 - 41.67 mm (1.6169 - 1.6405 inch)
Exhaust 41.00 - 41.60 mm (1.6142 - 1.6378 inch)

VALVE DIMENSIONS





Check dimensions of each valve.
When valve head has been worn down to 0.5 mm (0.020 inch) in margin thickness, replace valve.
Grinding allowance for valve stem tip is 0.2 mm (0.008 inch) or less.

VALVE SPRING
Squareness





1. Measure dimension "S".
Out-of-square "S": Less than 2.0 mm (0.079 inch)
2. If it exceeds the limit, replace spring.

Pressure





Check valve spring pressure at specified spring height.
Pressure:
Standard 196 N (20.0 kg, 44.1 lbs.) at height 37.0 mm (1.457 inch)
Limit More than 433 N (44.2 kg, 97.3 lbs.) at height 27.8 mm (1.094 inch)
If it exceeds the limit, replace spring.

VALVE LIFTER





1. Check contact and sliding surfaces for wear or scratches.
2. Check diameter of valve lifter and valve lifter guide bore.





Valve lifter outer diameter: 33.977 - 33.987 mm (1.3377 - 1.3381 inch)





Lifter guide bore diameter: 34.000 - 34.016 mm (1.3386 - 1.3392 inch)