Doosan D35S-5 Service Manual page 106

2. Camshaft
Camshaft bushings are lubricated by the oil
flowing through the oil passages leading from the
oil main gallery to each bushing.
3. Valve mechanism
The engine oil that has lubricated No. 1 camshaft
bushing passes through the oil hole and pipe
provided at the top portion of crankcase to the
cylinder head. The engine oil then goes through
the front rocker shaft bracket into the rocker shaft,
lubricating each rocker bushing. At the same time,
it lubricates valve cap and valve stem of the
rocker. The oil then passes through the push rod
holes in the cylinder head and crankcase to
lubricate the tappets and camshaft cams before
returning to the oil pan.
D439E Service Manual 104 2. Engine Mechanical System (D439E)