TEO-540-A1A Engine Maintenance Manual
© 2021 Avco Corporation. All Rights Reserved
72-30
February 2021
Page 143
YO-233-B2A Engine Maintenance Manual
J.
Ream the valve guide as follows:
(1)
Apply force on the reamer to ensure the reamer has gone through the full length of the
valve guide. The 1-in. (2.54 cm) pilot must be visible through the exhaust port or through
the spark plug hole using an angled mirror.
(2)
Clean the valve guide per the “Hard Carbon Removal” procedure in Chapter 05-30.
(3)
Measure the inner diameter of the valve guide using the correct plug gage.
(4)
Examine the reamed hole to see if the reamer has cut all the way to the exhaust port end
of the guide. If it has not, and the exhaust port end of the hole looks dark, the valve guide
is bell-mouthed and must be replaced. Send the engine cylinder to an authorized vendor
who can complete this replacement.
(5)
If the valve guide is acceptable, apply lubricant to the valve guide.
CAUTION
NEVER USE THE PISTON TO PUSH THE VALVE THROUGH THE
GUIDE.
K.
Install the valves that are satisfactory, in the corresponding position from where valves were
removed. Refer to the “Intake Valve Installation” and “Exhaust Valve Installation”
procedures in this chapter.
L.
Install the valve springs and valve spring seats (Figure 15).
M.
Remove and clean the hydraulic lifter and remove all oil.
N.
Examine the lifter for any malfunction.
O.
Clean the inner diameter of the tappet body.
P.
Install the hydraulic lifter.
Q.
Install the cylinder in the same position as removed. Refer to the “Cylinder Installation”
procedure in this chapter.
R.
Examine, rotate (as needed), and install serviceable spark plugs per the “Spark Plug
Inspection,” “Spark Plug Rotation,” and “Spark Plug Installation” procedures in Chapter 74-
20.
22.
Intake and Exhaust Valve Guide Replacement
Any time a valve guide (Figure 15) is to be replaced, send the engine cylinder to an authorized
vendor who can complete this replacement.
23.
Intake and Exhaust Valve Seat Replacement
If an intake or exhaust valve seat (Figure
55) is damaged or must be replaced, send
the engine cylinder to an authorized vendor
who can complete this replacement.
Figure 55
Intake and Exhaust Valve Seats