370
Section 4 Engine Service
9. When new or reconditioned valves are being
installed in guides, what should be placed on
the valve stems fi rst?
10. How is valve clearance checked on an
overhead valve engine?
11. Why should valve cover screws never be
tightened excessively?
12. What two methods are typically used to
adjust crankshaft endplay?
13. Why should lawn mower engines be
reinstalled in the equipment before they are
test run?
14. True or False? Engine oil should be changed
after the fi rst hour of operation following an
engine overhaul.
15. Some manufacturers require the to be
retorqued after a certain number of hours of
operation following an engine overhaul.
Suggested Activities
1. Replace oil seals in the crankcase.
2. Time the camshaft to the crankshaft.
3. Measure crankshaft bearing clearances with
Plastigage and telescoping gauges.
4. Install new main and rod bearing inserts.
Observe rules of cleanliness and torque rod
bolts to specifi ed value.
5. Using an old ring, demonstrate the method of
dressing ring ends with a fi le to increase ring
end gap.
6. Replace piston rings with a ring expander.
7. Using ring compressor, replace a
reconditioned piston assembly in the cylinder.
8. Adjust valve clearances in an overhead valve
assembly.