Yanmar 4BY - Determining Cylinder Head Gasket Thickness

ENGINE
BY Service Manual
5-31
Cylinder Head
Determining Cylinder Head Gasket
Thickness
1. Thoroughly clean all old gasket material from
the cylinder head gasket surface of the cylinder
block.
2. Clean all carbon and deposits from measuring
locations of each piston.
Figure 5-33
3. Place a dial indicator with measuring fixture
OEM No. 00 2 530 on clean cylinder block
(Figure 5-33). Set dial to zero.
4. Rotate the crankshaft to bring piston to the top
of its stroke.
Figure 5-34
5. Slide fixture and indicator over cleaned area of
piston (Figure 5-34, (1)). Rotate the crankshaft
to determine the highest point of piston travel
and record the measurement. Repeat the
procedure in a second area (Figure 5-34, (2)).
6. Measure all pistons in the same manner.
Figure 5-35
7. Select the lesser measurement for all pistons
and use the following chart to choose the
correct gasket. Gasket thickness is identified by
the number of holes (Figure 5-35, (arrow)).
Cylinder Head Gasket Identification
0003768
(
1
)
(
2
)
Engine Measured Distance Gasket
4BY / 6BY
0.72 - 0.83 mm
(0.028 - 0.033 in.)
1-hole
0.83 - 0.93 mm
(0.033 - 0.037 in.)
2-hole
0.93 - 1.04 mm
(0.037 - 0.041 in.)
3-hole
1.04 - 1.24 mm
(0.041 - 0.049 in.)
0-hole