Inspection - DeWalt DW168F Manual

Inspection

ValVE spRInG FREE lEnGTh
measure the free length of the valve
springs.
MoDEl sTanDaRD sERVICE
(MM) lIMIT (MM)
Dw168 30 ~ 31 29.0
Dw177 38.5 ~ 39.5 37.5
Dw188 38.5 ~ 39.5 37.5
noTE: Replace the springs if they are
shorter than the service limit.
ValVE sEaT WIDTh
measure the valve seat width.
MoDEl sTanDaRD sERVICE
(MM) lIMIT (MM)
Dw168 0.7 ~ 0.9 2.0
Dw177 0.7 ~ 0.9 2.0
Dw188 0.7 ~ 0.9 2.0
noTE: Recondition the valve seat if the
width is under the standard or over the
service limit.
CylInDER hEaD
waRnIng: Always wear certified safety equipment: ANSI Z87.1 eye protection (CAN/
CSA Z94.3) with side shields when removing carbon deposits.
waRnIng: To reduce the possibility of fire or explosion, be careful when working around
gasoline. Use only a nonflammable solvent, not gasoline, to clean parts. Keep smoking
products, sparks and flames away from all fuel related parts.
• Remove carbon deposits from
combustion chamber using a wire
brush.
• Remove any gasket material from
cylinder head surface.
• Check the spark plug hole and valve
areas for cracks.
• Check the cylinder head for warpage
with a straight edge and a feeler
gauge.
sTanDaRD sERVICE lIMIT
(MM) (MM)
0 0.10
CALIPER
VALVE
SEAT
STRAIGHT
EDGE
fEELER
GAUGE
ValVE sTEM o. D.
Inspect each valve for:
• surface irregularities
• bending
• stem wear
Replace valve if needed.
measure and record each valve stem O. D.
Service
Standard
modeL Limit
(mm)
(mm)
In 5.468~5.48 5.318
dW168
EX 5.418~5.44
5.275
In
6.568~6.580 6.440
dW177
EX 6.545~6.560 6.400
In 6.568~6.580 6.440
dW188
EX 6.545~6.560
6.400
noTE: Replace the valves if the O. D. is smaller than the service limit.
ValVE GuIDE I. D.
noTE: ream the valve guides to remove any
carbon deposits before measuring.
measure and record each valve guide I. D.
sERVICE
sTanDaRD
lIMIT
MoDEl
(MM)
(MM)
dW168
5.500~5.512 5.572
dW177
6.600~6.615 6.660
dW188
6.600~6.615 6.660
noTE: Replace the valve guides if the I. D. Is
over the service limit.
GuIDE To sTEM ClEaRanCE
Subtract each valve stem O. D. from the
corresponding guide I. D. to obtain the
stem to guide clearance.
sERVICE
sTanDaRD
MoDEl lIMIT
(MM)
(MM)
In 0.020~0.044 0.10
dW168
EX 0.060~0.084 0.12
In
0.020~0.070 0.11
dW177
EX 0.040~0.070 0.15
In 0.020~0.070 0.11
dW188
EX
0.040~0.070 0.15
44
mICROmETER
REAmING TOOL
VALVE
GUIDE
DIAL INDICATOR
bORE GAUGE