MLA (Mechanical Lash Adjuster)
- Inspect the MLA. Using a micrometer, measure the MLA outside diameter. MLA outer diameter: 31.964 ~ 31.980 mm (1.2584 ~ 1.2590 in.)
- Using a caliper gauge, measure MLA tappet bore inner diameter of cylinder head. Tappet bore inner diameter: 32.000 ~ 32.025 mm (1.2598 ~ 1.2608 in.)
- Subtract MLA outside diameter measurement from tappet bore inside diameter measurement.
MLA to tappet bore clearance
(Standard) : 0.020 ~ 0.061 mm (0.00078 ~ 0.00240 in.)
(Limit) : 0.070 mm (0.00275 in.)
Scheme 147
Scheme 148
Scheme 149
Scheme 150
- Inspect the cam lobes. Using a micrometer, measure the cam lobe height. Cam height (Standard value) Intake : 44.10 ~ 44.30 mm (1.7362 ~ 1.7440 in.) Exhaust : 44.90 ~ 45.10 mm (1.7677 ~ 1.7756 in.) If the cam lobe height is less than standard, replace the camshaft.
- Inspect the camshaft journal clearance. Clean the bearing caps and camshaft journals. Place the camshafts on the cylinder head. Lay a strip of plastigage across each of the camshaft journal. Install the bearing caps. CAUTION: Do not turn the camshaft. Remove the bearing caps. Measure the plastigage at its widest point. Bearing oil clearance (Standard value) Intake : No. 1 : 0.022 ~ 0.057 mm (0.00087 ~ 0.00224 in.) No. 2, 3, 4, 5 : 0.030~0.067 mm (0.00118 ~ 0.00264 in.) Exhaust: No. 1 : 0 ~ 0.032 mm (0 ~ 0.00126 in.) No. 2, 3, 4, 5 : 0.030~0.067 mm (0.00118 ~ 0.00264 in.) (Limit) Intake: No. 1 : 0.090 mm (0.00354 in.) No. 2, 3, 4, 5 : 0.120 mm (0.00472 in.) Exhaust : No. 1 : 0.090 mm (0.00354 in.) No. 2, 3, 4, 5 : 0.120 mm (0.00472 in.) If the oil clearance is greater than maximum, replace the camshaft. If necessary, replace cylinder head. Completely remove the plastigage. Remove the camshafts.
- Inspect the camshaft end play. Install the camshafts. Using a dial indicator, measure the end play while moving the camshaft back and forth. Camshaft end play (Standard value) : 0.04 ~ 0.16 mm (0.0016 ~ 0.0063 in.) (Limit) : 0.20 mm (0.0078 in.) If the end play is greater than maximum, replace the camshaft. If necessary, replace cylinder head. Remove the camshafts.
Exhaust Camshaft Bearing
- Check the cylinder head bore mark.
Scheme 151
Cylinder Head Bore Identification Mark
| Class | Mark | Exhaust No. 1 Inside Diameter Of Cylinder Head Bore |
|---|---|---|
| A | A | 40.000 ~ 40.008 mm (1.57480 ~ 1.5751 in.) |
| B | B | 40.008 ~ 40.016 mm (1.57511 ~ 1.57543 in.) |
| C | C | 40.016 ~ 40.021 mm (1.57543 ~ 1.57563 in.) |
CYLINDER HEAD SPECIFICATIONS CHART
- 2. Select class of camshaft bearing same as class of cylinder head as shown on the table below.
Scheme 152
Exhaust Camshaft Bearing Specifications
| Cylinder Head Bore Class | Bearing Class For Installing (Color) | Thickness Of Bearing |
|---|---|---|
| A (A) | C (Green) | 1.996~2.000 mm (0.07858~0.07874 in.) |
| B (B) | B (None color) | 2.000~2.004 mm (0.07874~0.07890 in.) |
| C (C) | A (Black) | 2.004~2.008 mm (0.07890~0.07905 in.) |
EXHAUST CAMSHAFT BEARING REFERENCE CHART
Oil clearance : 0 ~ 0.032 mm (0 ~ 0.00126 in.)