Section 9: Valve Train; Major Components; Disassembly - Generac Power Systems GN190H Service And Repair Manual

SECTION 9: VALVE TRAIN

MAJOR COMPONENTS

Valve train components are shown in Figure 9.1 below.
8
7
9
10
11
12
ITEM QTY DESCRIPTION
1 2 Tappet
2 2 Push Rod
3 1 Intake Valve
4 1 Exhaust Valve
5 1 Valve Stem Seal
6 2 Valve Spring Wear Washer
7 2 Valve Spring
8 2 Valve Spring Retainer
9 2 Pivot Ball Stud
10 2 Rocker Arm
11 2 Rocker Arm Jam Nut
12 1 Push Rod Guide Plate
Figure 9.1 — Valve Train Components

DISASSEMBLY

1.Remove the oil breather tube. Remove the four M6-
1.00 x 12mm screws. Then, remove the rocker arm
cover (see Figure 9.2).
Figure 9.2 — Removal of Rocker Arm Cover
6
5
4
3
NOTE: Whenever the rocker arm cover is removed, the
cover gasket must be replaced to ensure a proper seal.
2. Loosen the rocker arm jam nuts on the pivot ball studs.
Then, loosen the pivot ball studs. Remove the two pivot
ball studs, rocker arms and jam nuts. Also, remove the push
rod guide plate.
NOTE: Keep intake and exhaust valve parts separated.
Intake and exhaust pivot ball studs, rocker arms and
push rods are identical. However, the wear patterns will
be different.
2
1
Figure 9.3 — Rocker Arms and Push Rod Guide Plate
3. Remove the PUSH RODS (see Figure 9.3).
4. Remove the CYLINDER HEAD BOLTS, then the CYLINDER
HEAD and CYLINDER HEAD GASKET (see Figure 9.4).
NOTE: Replace the cylinder head gasket every time the
cylinder head is removed. The new cylinder head gasket
must be free of nicks and scratches as these could cause
leaks.
CYLINDER
HEAD
BOLTS
Figure 9.4 — Cylinder Head Removal
32
CYLINDER
HEAD
CRANKCASE
CYLINDER
HEAD GASKET