Valve Tappet Check

Fig. 10 Sectional view of camshaft & valve tappet:

1. Start and operate engine at approximately 3000 RPM for 5 minutes.
2. Remove cylinder head cover.
3. Place lobe of valve tappet on base circle with lobe pointing upward, Fig. 10.
4. Using a suitable tool, push or try to push valve tappet manually. If compared with the other valves, the valve tappet drops quickly or if the valve tapped has excessive play in relation to base circle of lobe, perform step 6, then 8. If the valve tappet has play, or if the sinking time (when tappet is pushed) is too short, check basic position steps 5 through 7.
5. Using a dial indicator placed on measuring bridge tool 601589082100 or equivalent, measure and note cylinder head parting surface to valve tappet dimension. Place measuring bridge over tappet to be checked on the cylinder head parting surface. If necessary, measure this dimension on all the valves.
6. Remove fan and fan cover.
7. Remove camshaft assembly.
8. Measure cylinder head parting surface to valve tappet dimension. The difference between dimension obtained in step 5 and step 8 is the initial stroke (installation position). The nominal value when valve tappet is new should be .0098-.0629 inch (.25-1.6 mm). The nominal value on a used valve tappet should be .0098-.0984 inch (.25-2.5 mm).
9. If the valve tappet sinks quickly or if the nominal dimension in step 8 is not obtained or exceeded, remove valve tappet.

Fig. 11 Measuring valve tappet dimensions:

10. Measure and note valve tappet dimension L, Fig. 11.
11. Measure and note valve tappet dimension L2, Fig. 11. Dimension L1 (dimension between L and L2) should be .708-.748 inch (18-19 mm).
12. If dimension L1 is higher or lower, remove guide sleeve. Using suitable pliers, remove guide sleeve from valve tappet. Do not damage guide sleeve.
13. Pull thrust bolt out of guide sleeve and remove compression spring.
14. Using compressed air, blow out all dirt from components. Blow through the valve tappet at the oil feed hole.
15. Remove snap ring from guide sleeve, then bend snap ring edges slightly and install into guide sleeve.
16. Assemble guide sleeve, compression spring and thrust pin into tappet.
17. Fill thrust pin with clean engine oil. Press on ball valve and close ball valve. Add oil, if necessary. Using a suitable tool, apply force on ball valve. No oil should flow out of ball. If oil flows out, replace valve tappet.
18. Fill valve tappet with clean engine oil and install vented thrust pin with guide sleeve into valve tappet. Push guide sleeve into valve tappet until snap ring engages ring groove.
19. Check dimension L1, refer to steps 9 and 10.
20. Loosen closing plug on oil duct on cylinder head and check oil supply.
21. Lubricate, then install valve tappets.
22. Install camshaft, cylinder head cover, fan and fan cover.
23. Operate engine and check for proper operation.