Inspection Piston/Pin/Ring - Mitsubishi 4G1 Service Manual

INSPECTION
PISTON
(1) Replace the piston if scratches or seizure is evident on its
surfaces (especially the thrust surface). Replace the piston
if it is cracked.
PISTON PIN
(1) Insert the piston pin into the piston pin hole with a thumb.
You should feel a slight resistance. Replace the piston pin if
it can be easily inserted or there is an excessive play.
(2) The piston and piston pin must be replaced as an assembly.
PISTON RING
breakage and replace if defects are evident. If the piston
has been replaced with a new one, the piston rings must
also be replaced with new ones.
(2) Check for the clearance between the piston ring and ring
groove. If the limit is exceeded, replace the ring or piston, or
both.
Standard value:
No. I
SOHC 4663, DOHC Non-turbo
0.02
SOHC 4664, DOHC Turbo
0.03
No.
2
SOHC 4G63, DOHC
0.02
SOHC 4664
0.03
Limit: 0.1 mm (.004 in.)
(3) Install the piston ring into the cylinder bore. Force it down
with a piston, its crown being in contact with the ring, to
correctly position it at right angles to the cylinder v\;all. Then,
measure the end gap with a feeler gauge.
If the ring gap is excessive, replace the piston ring.
Standard value:
No. I
SOHC
0.25
DOHC
0.25
No.
2
SOHC - 8VALVE, DOHC
0.45
SOHC - IGVALVE
Oil ring
SOHC - 8VALVE
0.20
SOHC - IGVALVE
0.10 - 0.40
DOHC
0.13 - 0.38
Limit:
No. 1, No. 2
Oil
TSB Revision
m m (.OOOS - .0024 in.)
0.06
m m (.0017 - .0028 in.)
0.07
m m (.OOOS - .0024 in.)
0.06
m m
0.07
m m (.0098 - .0138 in.)
0.35
m m (.0098 - .0157 in.)
0.40
m m (.0177 - .0236 in.)
0.60
m m (.Ol57 - .0217 in.)
m m (.0079 - .0236 in.)
0.60
m m (.0039 - .0157 in.)
m m (.0051 - .0150 in.)
mm (.031 in.)
0.8
in.)