Removal
1. Remove the cylinder head cover (see Section 4), drive belt and toothed pulley (see Section 7).
2. Remove the ignition distributor (see Chapter 5).
3. Loosen the locknuts of the adjusting bolts and, by unscrewing them, close all the valves (see Chapter 1). Measure the axial clearance of the camshaft using an indicator head. If the clearance is outside the permissible limits, then the camshaft or cylinder head should be replaced or the necessary clearance should be provided using special washers - spacers.
Fig. 10.3 Checking the axial clearance of the camshaft using a dial indicator. Move the shaft back and forth as shown by the arrows
4. Loosen the rocker arm shaft mount bolts approximately ¼ turn in a crisscross pattern. Once all bolts are loosened, remove the rocker arm shaft assemblies.
Leave the strut mounting bolts in their holes to avoid disassembling the unit under the action of the spacer springs.
Fig. 10.4 Loosen the rocker arm axle support bolts (arrows)
5. Remove the camshaft and clean it.
Inspection
6. Visually assess the condition of the camshaft lobes and journals. Determine the presence of wear, pitting, rubbing, metal piling and signs of overheating (tarnished colors, discolored areas). Determine the presence of peeling of the hard surface layer of each cam.
7. Using a micrometer, measure the height of each cam.
If the measured cam lobe height value is less than the specified value, replace the camshaft.
8. Determine the clearances in the camshaft bearings in the following order:
- a) wash the bearing caps and shaft journals in gasoline or diesel fuel and wipe dry.
- b) Carefully insert the shaft into the head bed. Do not rotate the shaft during measurements.
- c) Place pieces of plastic gauge on each shaft journal.
- d) install the rocker arm axle assembly in place and tighten the strut bolts by hand.
- d) tighten the bolts to the torque specified in the specification, in ¼ turn increments in the sequence shown in Fig. 10.8a.
Fig. 10.8a Sequence of tightening the rocker arm axle strut bolts
Fig. 10.8b Comparison of the width of crushed gauges with a scale for determining the clearance in the bearing
- e) Unscrew the bolts as indicated in point 4 and remove the rocker arm axle assembly.
- g) compare the thickness of the crushed calibers (8 at the widest point) with a scale on the envelope with gauges (see fig. 10.86).
- c) if the measured clearance is greater than the permissible value, the camshaft and/or cylinder head should be replaced.
- i) scrape off any remaining plastic gauges from the shaft journals.
9. Remove the rocker arm support mounting bolts and remove the parts from the rocker arm shafts. Store the parts in the same order they were on the shaft.
Fig. 10.9 Assembling the rocker arm axle unit (carburetor engines)
10. Visually determine the presence of wear on the ends of the rocker arms and their bearings. Determine the condition of the adjusting screws and lock nuts, the surfaces of the bearing caps, springs and bushings.
11. Using a micrometer, determine the diameter of the rocker arm axles at the rocker arm operating points.
12. Measure the inner diameter of the rocker arm bearings. Based on the measurement results, determine the clearances in the corresponding bearings.
13. If the gaps are larger than the permissible limits, replace the worn parts.
Installation
14. Assemble the rocker shaft and insert the bolts into the strut holes to prevent spontaneous disassembly. All mating surfaces and oil supply holes must be clean and lubricated with engine oil.
15. Place the camshaft in the cylinder head bed so that the keyway faces upward.
16. Install the camshaft oil seal (if necessary see Section 9), lubricating the edges with engine oil.
17. Install the rocker arm axle assembly and tighten the strut bolts by hand
18. Tighten the strut mounting bolts in ¼ turn increments in the sequence shown in Fig. 10.8a to the force described in the specification.
19. Install the key and insert the camshaft timing pulley. Tighten the timing pulley mounting bolt to the torque specified in the specification. To prevent the shaft from turning, insert a large screwdriver or ratchet into the timing pulley hole. Make sure that the timing marks on the timing pulley are correctly aligned with the cylinder head (see fig 7.22).
20. Install the drive belt and removed components in the reverse order of removal.
(The text of the article is available on the website HONDABOOK)