Caution: Be sure to identify each removed part as to its location, and lay the parts out in groups designated as "No.1", "No.2", "Exhaust", "Intake", so that each will be restored to the original location during assembly.
Camshaft
All camshafts should be checked for runout and also for wear of cams and journals if the engine has been noted as giving abnormal noise, vibration or lack power output. Any of these conditions may be caused by camshafts worn down or distorted to the service limit.
The camshafts can be identified by the engraved letter.
- (1) No.1 (Front) intake camshaft ("INF" and "I": Intake)
- (2) No.1 (Front) exhaust camshaft ("EXF" and "E": Exhaust)
- (3) No.2 (Rear) intake camshaft ("INR" and "I": Intake)
- (4) No.2 (Rear) exhaust camshaft ("EXR" and "E": Exhaust)
Cam wear
Worn-down cams are often the cause of mistimed valve operation resulting in reduced power output.
The limit of cam wear is specified for both intake and exhaust cams in terms of cam height (H), which is to be measured with a micrometer. Replace camshaft if it wears worn down to the limit.
Cam height (H)
- Service Limit (IN): 35.98 mm (1.417 in)
- (EX): 35.38 mm (1.393 in)
09900-20202: Micrometer (25-50 mm)
Camshaft journal wear
Determine whether or not each journal is worn down to the limit by measuring the oil clearance with the camshaft installed in place. Use the plastigauge (A) to read the clearance at the widest portion, which is specified as follows:
Camshaft journal oil clearance
- Service Limit (IN & EX): 0.150 mm (0.0059 in)
- 09900-22301: Plastigauge
- 09900-22302: Plastigauge
Note:
- Install camshaft journal holder to their original positions.
- Tighten the camshaft journal holder bolts evenly and diagonally to the specified torque.
Camshaft journal holder bolt: 10 Nm (1.0 kgf·m, 7.0 lb·ft)
Note:
- Do not rotate the camshaft with the plastigauge in place.
- Remove the camshaft holders, and read the width of the compressed plastigauge with envelope scale. This measurement should be taken at the widest part.
If the camshaft journal oil clearance measured exceeds the limit, measure the inside diameter of the camshaft journal holder and outside diameter of the camshaft journal. Replace the camshaft or the cylinder head depending upon which one exceeds the specification.
Camshaft journal holder I.D.
Standard (IN & EX):
- 22.012 - 22.025 mm (0.8666-0.8671 in)
- 09900-20602: Dial gauge (1/1000, 1 mm)
- 09900-22403: Small bore gauge (18-35 mm)
Crankshaft journal O.D.
Standard (IN & EX):
- 21.972 - 21.993 mm (0.8650 - 0.8659 in)
09900-20205: Micrometer (0-25 mm)
Camshaft runout
Measure the runout with a dial gauge. Replace the camshaft if the runout exceeds the limit.
Camshaft runout
- Service Limit (IN & EX): 0.10 mm (0.004 in)
- 09900-20607: Dial gauge (1/100 mm, 10 mm)
- 09900-20701: Magnetic stand
- 09900-21304: V-block (100 mm)
- Cam gear and automatic-decomp.
- Inspect the cam gear teeth for wear and damage.
- Inspect the automatic-decomp, for damage and smooth operation.
- If there are unusual, replace the camshaft assembly and cam chain as a set.
Caution: Do not attempt to disassemble the cam gears and automatic-decomp, assembly. They are unserviceable.