Camshaft: Testing and Inspection
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: 0.080 mm (0.0031 in).
3. 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: 42.210-42.310 mm (1.6618-1.6657 in).
Exhaust: 41.960-42.060 mm (1.6520-1.6559 in).
Minimum cam lobe height:
Intake: 42.060 mm (1.6559 in).
Exhaust: 41.810 mm (1.6461 in).
2. If the cam lobe height is less than minimum, replace the camshaft.
CAMSHAFT JOURNAL DIAMETER
1. Using a micrometer, measure the journal diameter.
Journal diameter:
Exhaust camshaft thrust bearing journal, (A) in illustration: 23.959-23.975 mm (0.9433-0.9439 in).
All other camshaft journals: 26.954-26.970 mm (1.0612-1.0618 in).
2. If the journal diameter is not as specified, check the oil clearance.
CAMSHAFT GEAR SPRING
1. Using vernier calipers, measure the free distance between the spring ends.
Free distance: 18.200-18.800 mm (0.7120-0.7400 in).
2. If the free distance is not as specified, replace the gear spring.
CAMSHAFT BEARING SURFACE
Check that bearings for flaking and scoring. If the bearings are damaged, replace the bearing caps and cylinder head as a set.
CAMSHAFT JOURNAL OIL CLEARANCE
1. Clean the bearing caps and camshaft journals.
CAUTION: If this procedure is to be performed with valves, springs and lifters installed, refer to the following, otherwise the cams may be installed, each bearing cap may be tightened to 16 Nm (160 kg.cm, 12 ft.lb), removed and the Plastigage measured in the normal manner.
- If cylinder heads are installed to engine, to prevent valve/piston contact, the crankshaft must be set as shown in the illustration.
- If cylinder heads are removed, ensure there is sufficient clearance below head for valves to open when camshafts are tightened into place.
- Since the thrust clearance of the camshaft is small, the camshaft must be kept level while it is being installed.
- If the camshaft is not kept level, the portion of the cylinder head receiving the shaft thrust may crack or be damaged causing the camshaft to seize or break.
- To avoid this, the following steps should be carried out.
2. Place the camshafts on the cylinder head as outlined below.
NOTE: Do not turn the camshaft.
3. Lay a strip of Plastigage across each of the camshaft journals.
4. Install the bearing caps as follows:
RH INTAKE CAMSHAFT:
(a) Place the intake camshaft at 45° angle of the timing mark (1 dot mark) on the cylinder head.
(b) Install the front bearing cap (mark "I6" ) with the arrow mark facing rearward.
NOTE: Installing the front bearing cap will determine the thrust portion of the camshaft. Align the arrow marks at the front and rear of the cylinder head with the mark on the bearing cap.
(c) Install the other bearing cap in the sequence shown with the arrow mark facing rearward.
NOTE: Align the arrow marks at the front and rear of the cylinder head with the mark on the bearing cap.
(d) Apply a light coat of engine oil on the threads and under the heads (A only) of the bearing cap bolts.
NOTE: Do not apply engine oil under the heads of the bearing cap bolt (B).
(e) Install a new seal washer to the bearing cap bolt (B Install the eight bearing cap bolts as shown.
NOTE:
- Use bearing cap bolts 38 mm (1.50 in) in length. The bolts are black (A) or silver (B) in color. Install the two silver bolts to the front bearing cap.
- Install the six black bolts to the other positions.
- After installing the oil feed pipe, install the two bolts to rear bearing cap as directed in step B found under RH EXHAUST CAMSHAFT below.
(f) Uniformly tighten the eight bearing cap bolts in several passes, in the sequence shown to 16 Nm (160 kg.cm, 12 ft.lb).
RH EXHAUST CAMSHAFT:
(a) Set the timing mark (1 dot mark) of the camshaft drive gear at 10° angle by turning the hexagon wrench head portion of the intake camshaft with a wrench.
(b) Align the timing marks (1 dot mark) of the camshaft drive and driven gears.
(c) Place the exhaust camshaft on the cylinder head.
(d) Install the rear bearing cap (mark "E1") with the arrow mark facing rearward.
NOTE:
- Installing the rear bearing cap will determine the thrust portion of the camshaft.
- Align the arrow marks at the front and rear of the cylinder head with the mark on the bearing cap.
(e) Install the other bearing cap in the sequence shown with the arrow mark facing rearward.
NOTE: Align the arrow marks at the front and rear of the cylinder head with the mark on the bearing cap.
(f) Apply a light coat of engine oil on the threads and under the heads of the bearing cap bolts.
(g) Install the oil feed pipe and 10 bolts.
NOTE: Use bearing cap bolts 38 mm (1.50 in) and 52 mm (2.05 in) in length. Use black colored 38 mm (1.50 in) bolts. Install the two 52 mm (2.05 in) bolts in outside positions of the oil feed pipe. Install the eight 38 mm (1.50 in) bolts in the other positions.
(h) Uniformly tighten the eight bolts on the bearing caps of the exhaust camshaft in several passes, in the sequence shown to 16 Nm (160 kg.cm, 12 ft.lb).
(i) Alternately tighten the two bolts on the rear bearing caps of the intake camshaft in several passes to 16 Nm (160 kg.cm, 12 ft.lb).
LH INTAKE CAMSHAFT:
(a) Place the intake camshaft at 60° angle of the timing mark (1 dot mark) on the cylinder head.
(b) Install the front bearing cap (mark "I1") with the arrow mark facing forward.
NOTE:
- Installing the front bearing cap will determine the thrust portion of the camshaft.
- Align the arrow marks at the front and rear of the cylinder head with the mark on the bearing cap.
(c) Install the other bearing cap in the sequence shown with the arrow mark facing forward.
NOTE: Align the arrow marks at the front and rear of the cylinder head with the mark on the bearing cap.
(d) Apply a light coat of engine oil on the threads and under the heads (A only) of the bearing cap bolts.
NOTE: Do not apply engine oil under the heads of the bearing cap bolt (B).
(e) Install a new seal washer to the bearing cap bolt (B). Install the eight bearing cap bolts as shown.
NOTE:
- Use bearing cap bolts 38 mm (1.50 in) in length. The bolts are black (A) or silver (B) in color. Install the two silver bolts to the front bearing cap. Install the six black bolts to the other positions.
- After installing the oil feed pipe, install the two bolts to the bearing cap second from the front as directed in step B (i).
(f) Uniformly tighten the eight bearing cap bolts in several passes, in the sequence shown, tighten to 16 Nm (160 kg.cm, 12 ft.lb).
LH EXHAUST CAMSHAFT:
(a) Set the timing mark (2 dot marks) of the camshaft drive gear at 15° angle by turning the hexagon wrench head portion of the intake camshaft with a wrench.
(b) Align the timing marks (2 dot marks) of the camshaft drive and driven gears.
(c) Place the exhaust camshaft on the cylinder head.
(d) Install the front bearing cap (mark "E1") with the arrow mark facing forward.
NOTE:
- Installing the front bearing cap will determine the thrust portion of the camshaft.
- Align the allow marks at the front and rear of the cylinder head with the mark on the bearing cap.
(e) Install the other bearing cap in the sequence shown with the arrow mark facing forward.
HINT: Align the arrow marks at the front and rear of the cylinder head with the mark on the bearing cap.
(f) Apply a light coat of engine oil on the threads and under the heads of the bearing cap bolts.
(g) Install the oil feed pipe and 10 bolts.
NOTE: Use bearing cap bolts 38 mm (1.50 in) and 52 mm (2.05 in) in length. Use black colored 38 mm (1.50 in) bolts. Install the two 52 mm (2.05 in) bolts in outside positions of the oil feed pipe. Install the eight 38 mm (1.50 in) bolts in the other positions.
(h) Uniformly tighten the eight bolts on the bearing caps of the exhaust camshaft in several passes, in the sequence shown and tighten to 16 Nm (160 kg.cm, 12 ft.lb).
(i) Alternately tighten the two bolts on the bearing cap of the intake camshaft second from the front in several passes to 16 Nm (160 kg.cm, 12 ft.lb).
5. Remove the bearing caps as follows:
RH EXHAUST CAMSHAFT:
(a) Alternately loosen and remove the two bearing cap bolts holding the intake camshaft side of the oil feed pipe to the cylinder head.
(b) Uniformly loosen and remove the eight bearing cap bolts in several passes, in the sequence shown.
(c) Remove the oil feed pipe, four bearing caps and exhaust camshaft.
RH INTAKE CAMSHAFT:
(a) Remove the rear bearing cap.
(b) Set the timing mark (1 dot mark) of the camshaft drive gear at approx. 45° angle by turning the hexagon wrench head portion of the intake camshaft with a wrench.
(c) Uniformly loosen and remove the eight bearing cap bolts in several passes, in the sequence shown.
(d) Remove the four bearing caps, oil seal and intake camshaft.
LH EXHAUST CAMSHAFT:
(a) Set the timing mark (2 dot marks) of the camshaft drive gear at approx. 15° angle by turning the hexagon wrench head portion of the exhaust camshaft with a wrench.
(b) Alternately loosen and remove the two bearing cap bolts holding the intake camshaft side of the oil feed pipe to the cylinder head.
(c) Uniformly loosen and remove the eight bearing cap bolts in several passes, in the sequence shown.
(d) Remove the oil feed pipe, four bearing caps and exhaust camshaft.
LH INTAKE CAMSHAFT:
(a) Remove the bearing cap second from the front.
(b) Set the timing mark (1 dot mark) of the camshaft drive gear at approx. 60° angle by turning the hexagon wrench head portion of the intake camshaft with a wrench.
(c) Uniformly loosen and remove the eight bearing cap bolts in several passes, in the sequence shown.
(d) Remove the four bearing caps, oil seal and intake camshaft.
NOTE: Arrange the bearing caps in correct order
6. Measure the Plastigage at its widest point.
Standard oil clearance:
Exhaust camshaft thrust journal: 0.025-0.061 mm (0.0010-0.0024 in).
All other journals: 0.030-0.067 mm (0.0012-0.0026 in).
Maximum oil clearance: 0.100 mm (0.0039 in).
7. If the oil clearance is greater than maximum, replace the camshaft and /or the bearing caps and cylinder head set as required.
8. Completely remove the Plastigage.
9. Remove the camshafts.
CAMSHAFT THRUST CLEARANCE
1. Install the camshafts as described under Camshaft Journal Oil Clearance above.
2. Using a dial indicator, measure the thrust clearance while moving the camshaft back and forth.
Standard thrust clearance: 0.040-0.090 mm (0.0016-0.0035 in).
Maximum thrust clearance: 0.120 mm (0.0047 in).
3. If the thrust clearance is greater than maximum, replace the camshaft and/or the bearing caps and cylinder head set as required.
4. Remove the camshafts as described under Camshaft Journal Oil Clearance above.
CAMSHAFT GEAR BACKLASH
1. Install the camshafts without installing the exhaust cam sub-gear as described under Camshaft Journal Oil Clearance above.
2. Using a dial indicator, measure the backlash.
Standard backlash: 0.020-0.200 mm (0.0008-0.0079 in).
Maximum backlash: 0.300 mm (0.0188 in).
3. If the backlash is greater then maximum, replace the camshafts.
4. Remove the camshafts as described under Camshaft Journal Oil Clearance above.