Install Cylinder Head - Yanmar BY Series Service Manual

Cylinder Head
12/05
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)).
Figure 5-34
Figure 5-34
6. Measure all pistons in the same manner.
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)).
Figure 5-35
Figure 5-35
Cylinder Head Gasket Identification
Engine Measured Distance
0.72 to 0.83 mm
(0.028 to 0.033 in.)
0.83 to 0.93 mm
(0.033 to 0.037 in.)
4BY2 / 6BY2
0.93 to 1.04 mm
(0.037 to 0.041 in.)
1.04 to 1.24 mm
(0.041 to 0.049 in.)
BY Service Manual

Install Cylinder Head

1. If the pistons, connecting rods or crankshaft
were refurbished or replaced, check piston
height to determine correct cylinder head
gasket thickness. See Determine Cylinder
Head Gasket Thickness on page 5-26. If those
items remain unchanged, select a gasket that
matches the one removed during disassembly.
2. Check condition and placement of alignment
dowel sleeves (Figure 5-36, (1)).
Figure 5-36
( 1 )
( 2 )
0003768
3. Ensure the gasket surfaces of the cylinder head
and cylinder block are clean and dry. Transition
areas (Figure 5-36, (2)) must be absolutely
clean of grease and oil. NOTICE: Ensure the
threaded bolt holes are clean and dry. If coolant
or oil remains in the holes, there is a risk of
cracking the cylinder block when the bolts are
installed.
4. Install a new cylinder head gasket having the
correct number of identification holes as
determined in step 1.
Gasket
5. Install the cylinder head.
1-hole
2-hole
3-hole
0-hole
© 2009 Yanmar Marine International
ENGINE
Figure 5-36
5-27