Question 4
(a) (i) Identify the sketch shown below:
(ii) Name the parts labelled V, W, X and Y.
(b) State one function each of the parts labelled V, W, and X.
(c) Explain the procedure for valve adjustment.
Observation
This question was extremely difficult for the candidates as they could not provide the required responses to various parts of the question. The required responses to the various parts of the question are:
(a) (i) An over-head valve operating mechanism or Push rod valve operating
mechanism
(ii) V is rocker arm or rocker
W is valve spring or spring
X is camshaft, cam lobe, cam or lobe
Y is push rod
(b) V is used to open the valve
W is used to close the valve
X is operates the cam follower/push rod and rocker arm
(c) The procedure for valve adjustment is:
turn the engine until the valve to be adjusted is fully closed, then slacken the locknut and the tappet screw to allow the specific feeler gauge to go in between the valve and the rocker arm freely. The tappet screw should be in position without turning before you turn the locknut tight. Remove the feeler gauge and re-insert in order to confirm the specified gauge is not too tight or too loose.