John Deere stx38 - Manual (Page 70)

3 - 38
4/23/97
REPAIR ENGINE
MEASURE CAMSHAFT END PLAY
1. Check that camshaft is seated in crankcase bore.
2. Measure play (A) between camshaft and straight
edge (spanning crankcase) using flat feeler gauge.
3. Use shims from Shim Kit as necessary until end
play is within specification.
Camshaft End Play Specification (with shims):
(Maximum) . . . . 0.076—0.127 mm(0.003—0.005 in.)
Shim Thickness Range:
The most commonly used shims are listed below.
Additional shims are available through the parts
catalogue.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.73 mm (0.29 in.)
. . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.75 mm (0.30 in.)
. . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.81 mm (0.32 in.)
. . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.86 mm (0.34 in.)
HYDRAULIC VALVE LIFTERS—
REMOVE AND INSTALL
1. Remove camshaft.
IMPORTANT: Used lifters are mated to their
camshaft lobes. Mark them for installation in the
correct bore.
2. Remove lifters (A).
3. Inspect lifters for wear, replace as necessary.
4. Coat lifters with engine oil and install in correct
bore.
5. Install camshaft.
HYDRAULIC VALVE LIFTERS—
INSPECTION
Reasons:
• If lifter noise continues after 20 minutes of running,
it is probably an indication of contamination or dirt
in the lifter preventing the check ball from seating.
Replace lifter.
• A lifter which suddenly gets noisy while engine is
running would probably be caused by trapped. If
noise is caused by contamination, replace lifter. If
noise is caused by trapped air, see Step 2 under
“Lifter Noise After Start-Up”.
• Lifter noise which appears or worsens as the
engine heats up is usually due to wear in the lifters
and other engine components, especially if engine
has considerable running hours or has not had
regular oil changes. Replaces lifters and other
internal engine components that do not meet wear
limit specifications.
• A situation where the lifter seems to pump up too
much, holds a valve open, causes loss of
compression or hard starting, indicates insufficient
clearance between the plunger and body. Replace
lifter.
IMPORTANT: Damaged or worn lifters usually
indicate a damaged camshaft. Check camshaft
before replacing lifters.
1. Inspect lifter face (B) for wear. Face should be flat
and smooth.
2. Use push rod to depress plunger (A). Plunger
should offer resistance but move smoothly.
3. Check that oil hole (C) is clear to inner piston.
4. Measure outside diameter of lifter.
M52093
A
M52094
A
M52095
B
A
C