Mitsubishi S4Q2 User Manual

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Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
CYLINDER HEADS AND VALVE
MECHANISM
ENGLISH
ENGINE MAIN PARTS
7. Refacing valve seat
Use the Valve seat cutter or valve seat grinder to
reface the valve seat. After refacing, grind the seat
lightly using #400 grade sandpaper inserted
between the cutter and valve seat.
8. Lapping valve in valve seat
Be sure to lap the valve in the valve seat after the
seat has been replaced.
1) Coat the valve face lightly with a lapping
compound.
2) Use the Valve lapper to lap the valve in the
seat. To lap, raise the valve off the seat, then
rotate the valve only a partial turn and strike it
against the seat.
3) Wash off the compound with diesel fuel.
4) Coat the valve face with engine oil, and again
lap the valve.
5) Check the valve face for contact.
Figure 32 Refacing valve seat
NOTE
a Cut or grind the valve seat only as needed
for refacing.
b Replace the valve seat if the seat width is
more than the repair limit as a result of wear
or cutting.
Figure 33 Lapping valve in valve seat
Compound
NOTE
a Do not permit the compound to come in
contact with the valve stem.
b Use a compound of 120 to 150 mesh for
initial lapping and the compound finer than
200 mesh for finish lapping.
c Mixing the compound with a small amount of
engine oil will facilitate coating.

Mitsubishi S4Q2 Specifications

General

Brand	Mitsubishi
Model	S4Q2
Category	Engine
Language	English