Generac Power Systems GTV99O User Manual

SECTION
5:
CYLINDER
HEAD
AND VALvEs
INSPEO
AND REPAIR
I
Check
cylinder head
(Figure
5-7). Be
sure allgasket
mate_
rialis
rernoved from
sudaces
before
checking.
Use
d
gasKer
scraper f necessary
a.Inspect
cylinder head for.r€cks
or damage.
b. Use
a sudace
plate
or straightedge
and check
q
inderhead
mounUng
sudace
for
distortion.
lf
mounting
surfaces
are distoned
more
than
.004"
(0.1
mm),
the
cylnder head
nrust be
replaced.
Note:
lt is not
fecommended
that cytinder
heao
moun.-
ing
surtaes
be rcsuiaced.
Figute
5-7. check
Cytindet
Head
Distottion
2.
Clean
thevalve
gu
des
and measurethe
r l.D.
lsing a sptit
ball
bore
gauge (Figure
5,8)
a. Replace head
if either
valve
guide
measures
7.06
mm
(0.278
in.)
or more.
REFACE VALVES
AND
SEATS:
1. Va lve
seats may
be reconditioned
using
a valve
seai
cutter
lf valve
seat k widerthan
dimensjon
shown
in Figure
5-9, a
narrcwing
cutter
should
be used to
ensure
that conEcr
area
of
valve
seat is
centered
on face
of valve
(Figure
5-tO)
a. use
a 60" cutter
to narrow
seat from
bottom
and
a i5.
cutterto narrow
seat from
top
(Figure
5-9).
Note: fi
valve seat
is loose
or uacked,
rcpla.e
cytinder
60'CUTTEF
15'CUTTER
Figurc
5-9.
Valve Seat
Dinensions
2. Valve
faces may
be resudaced
to
45..
See Figure
5_10 for
diraensions ior
valves.
3. Lap valves
and seats
with
a
valve
lapping
toot
ano valve
lapping
compound.
Note:
ln most
instances
it is morc
economi.at
to reptace
the valves than
to refa@
them,
r
T
Figute
5-10. Valve
Dinensions
4. Measure valve
stem
diarneier
at specified
distance
frcm
end
ofvalve,
as shown
n Figure
5 11.
Replace
if less
than 6_9 mm
(0.272
inchet,
or if
total cleaF
ance between
valve stem
and valve
gu
de
exceeds
O_12
mnr
(0.0047
in)
Figwe
5-8. Check
valve
guides
53

Generac Power Systems GTV99O Specifications

General

Brand	Generac Power Systems
Model	GTV99O
Category	Engine
Language	English