John Deere stx38 - Manual (Page 71)

4/23/97
3 - 39
ENGINE REPAIR
5. Measure inside diameter of crankcase lifter bore
(D).
6. Subtract lifter OD. from bore ID. to determine if
clearance is not within specification.
IMPORTANT: Make sure lifters are “PRIMED”
before installation and “BLED” before start up
to prevent damage to push rods or rocker arms.
See priming and bleeding procedure on page 3-
41.
7. Replace lifters that are worn or damaged. Replace
components as necessary.
Specification:
Valve Lifter To Bore Clearance (maximum)
. . . . . . . . 0.0124—0.0501 mm (0.0005—0.0020 in.)
Priming Procedure For Hydraulic Lifters
1. Place lifter in small container.
2. Pour 10W30 oil into container until oil is level with
top of lifter.
3. Place the end of one of the push rods into the
socket on top of the lifter and “pump” the lifter with
push rod until it feels solid.
4. Remove lifter from oil, let it drip off for a moment,
and install into appropriate bore in engine.
Bleed Procedure For Hydraulic Lifters
1. After installing cylinder head, rotate flywheel so
piston is at TDC (top-dead-center) between the
exhaust and intake strokes. At TDC, the rocker
arms will move alternately if the flywheel is rocked.
This allows for maximum pressure on the lifters.
2. Leave engine in this position and re-assemble
remaining engine parts.
3. After engine has been in this position for 10 minutes
(can include assembly time) turn engine over
slowly by hand.
4. If engine turns over completely, fill the crankcase to
proper level with recommended oil and test run.
5. If engine does not turn over completely (locks up at
some point), stop turning at the point of lockup and
allow 10 more minutes for the lifters to bleed down.
Then try rotating by hand again.
Results
• Lifter noise immediately after start-up is usually due
to contraction and/or leakdown. There will be some
noise when engine is first started but should last
only a few seconds, but no more than a few
minutes.
• If lifter is still noisy after 5 minutes of running, air
could be trapped in the lifter. Stop engine and
check oil level. Adjust as necessary and run
engine for an additional 20 minutes at half throttle.
BALANCER SHAFT REMOVAL &
INSTALLATION
1. Align marks (A) on balancer shaft and crankshaft.
2. Remove balancer shaft (B).
3. Inspect balancer shaft, replace as necessary.
4. Align marks (A) and install balancer shaft (B) so it
also aligns with governor gear (C).
5. Remember, when installing oil pan, be sure to align
flat (D) of balancer shaft with bore flat of oil pump
inner rotor gear.
M52097
D
M52099
B A
C
D