Camshaft And Tappets - Yanmar 4LHA-HTP Operation Manual

Chapter 2 Basic Engine

8. Camshaft and Tappets

8. Camshaft and Tappets
8-1 Camshaft
The camshaft is normalized and the cam and bearing
surfaces are surface hardened and ground. The cams have
a curve that minimizes the repeated shock on the valve
seats and maximizes valve seat life.
(1) Checking the camshaft side gap
The standard bearing near the end of the camshaft by
the cam gear receives the load, resulting in rapid wear
of the end of the bearing and enlargement of the side
gap. Therefore, measure the thrust gap before disas-
sembly. As the cam gear is shrink-fitted to the cam, be
careful when replacing the thrust bearing.
Standard
0.05 - 0.20
Camshaft side gap
(0.0020 - 0.0079)
Camshaft gear
Thrust metal
Side gap
mm (in.)
Wear limit
0.29
(0.0114)
Push rod
Thrust metal'
(2) Measure the cam height, and replace the cam if it
is worn beyond the limit.
Cam height
Intake cam
Exhaust cam
2-32
14LHA Series\
Camshaft gear
Wear limit
Standard
48.1
48.435 - 48.565
(1.9094)
(1.9069-1.9120)
48.1
48.435 - 48.565
(1.9094)
(1.9069-1.9120)
mm (in.)