Komatsu 4D98 Series Shop Manual page 52

4.
Engine Body
Point 6
Disassemble:
l
Keep the removed push rods by attaching tags showing corresponding cylinder Nos.
Reassemble:
l
Always apply oil to the contact portions of the push rods and valve clearance adjusting
screws.
Point 7
Disassemble:
l
Loosen the cylinder head bolts in two
steps in the illustrated order.
l
Place the cylinder head assy on a pa-
per board to prevent the combustion
face from any damage.
Reassemble:
Disassembly
Head bolt disassembly order
Remove the head gasket with a new
one.
Uniformly install the head bolts manu-
ally after applying oil on the threaded
and seat portions.
d
They shall be tightened in two steps in
the reverse of the order for disassem-
I
Head bolt tightening order
bly.
1
Tightening torque
Nm(kgf*m)
4TNE94.98
4TNE106 (T)
First step: 49-58.8 (5-6) 88.3-98.1 (9-10)
Second step: 102.9-112.7 (10.5-11.5) 181.4-191.2 (18.5-l 9.5)
Point 8
Disassemble:
l
Carefully remove the fuel injection valve so as not to leave the tip end protector from being
left inside the cylinder.
Reassemble:
l
Replace the fuel injection valve protec-
tor with a new one.
Point 9
Disassemble:
l
When removing each intake/exhaust,
valve from the cylinder head, use a
valve spring compressor (see 11 .I -4 in
\
4
&
Vahfe spring compressor
Chapter 11) and compress the valve spring and remove the valve cotter.
l
Keep each removed intake/ exhaust valve after attaching a tag showing the corresponding
cylinder No.
l
If cotter burr is seen at the shaft of each intake/exhaust valve stem, remove it with an oil-
stone and extract the valve from the cylinder head.
Reassemble:
l
Replace the stem seal with a new one when an intake/exhaust valve is disassembled.
l
Carefully install each valve after oil application so as not to damage the stem seal.
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