Yanmar 4LHA-HTP Operation Manual page 354

Chapter 2 Basic Engine
8. Camshaft and Tappets
8-2 Tappets
(1) The tappets are offset to rotate during operation and
thereby prevent uneven wearing. Check the contact of
each tappet and replace if excessivety or unevenly
worn.
Abnormal contact
Offset
NOTE: When removing tappets, be sure to keep them
separate fbr each cylinder and intake/exhaust
valve.
(2) Measure the outer diameter of the tappet, and replace if
worn beyond the limit.
Normal contact
Offset
2-34
Tappet stem outside dia.
Tappet guide hole inside
dia. (cylinder block)
Tappet stem and guide
hole oil clearance
(3) Measuring push rods.
Measure the length and bending of the push rods.
1 7 8 . 2 5 - 178.75
Push rod length
Push rod bend
Push rod dia.
,4LHA Series
mm (in.)
Wear limit
Standard
14.17
14.218-14.233
(0.5579)
(0.5598 - 0.5604)
1 4 . 2 4 9 - 14.270 14.30
(0.5630)
(0.5610-0.5618)
0 . 0 1 6 - 0 . 0 5 2
-
(0.0006 - 0.0020)
mm (in.)
Wear limit
Standard
-
0.03 or less 0.3
(0.0118)
(0.0012)
- •
8 (0.3150)