Question

(click image for an enlarged view)
in the illustration shown, the technician is measuring the camshaft:
a. bearing journal
b. endplay
c. base circle
d. lobe height

Explanation:

To determine the correct option, we analyze the camshaft measurement. The base circle of a camshaft is the circular part (the non - lobe, lower - diameter section) that the cam rests on. When measuring the camshaft's base circle, a micrometer or similar tool is used around this circular area. Option A (bearing journal) is for bearing - related measurements, not the base - circle - like measurement shown. Option B (endplay) is about axial movement, not a circular - diameter measurement. Option D (lobe height) measures the lobe's height, not the base circle. So the technician is measuring the camshaft's base circle.

Answer:

C. base circle