John Deere Valve Service Manual
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Engine Repair
CYLINDER HEAD, VALVES, AND CAMSHAFT
PRELIMINARY VALVE CHECKS
During disassembly, inspect the valve train for the
following malfunctions and causes.
Sticking Valves
Carbon deposits on valve stem
Worn valve guides
Warped valve stems
Cocked or broken valve springs
Worn or distorted valve seats
Insufficient lubrication
Warped, Worn, or Distorted Valve
Guides
Lack of lubrication
Cylinder head distortion
Excessive heat
Unevenly tightened cylinder head cap screws
Cylinder Head, Valves and Camshaft 20-05-1
Group 05
Camshaft Failures
Scored camshaft lobes due to inadequate lubrica-
tion
Excessive end play due to thrust plate wear
Broken or warped camshaft due to improper timing
Checking Valve Clearance
Four-Cylinder Engine
Distorted Cylinder Head and Cylinder
Head Gasket Leakage
Improperly tightened cylinder head cap screws
Faulty gasket installation
Incorrect gasket material
Excessive oil pressure
Improper cylinder liner height above cylinder block
Worn or Broken Valve Seats
Misaligned valves
Distorted cylinder head
Carbon deposits on seats due to incomplete com-
bustion
Valve spring tension too weak
Excessive heat
Improper valve clearance
Improper valve timing
Burned, Pitted, Worn, or Broken Valves
Worn or distorted valve seats
Worn valve guides
Insufficient cooling
Insufficient lubrication
Cocked or broken valve springs
Preignition
Improper engine operation
Improper valve train timing
Faulty valve rotators
Warped or distorted valve stems
"Stretched" valves due to excessive spring tension
Warped cylinder head
Bent push rods
Carbon build-up on valve seats
Rocker arm failure
Fig. 1-Sening "TOC"
1. Rotateengine to position No. 1 piston at TDC of
its compression stroke.
2. Turn flywheel until timing mark on flywheel lines
up with mark on housing (Fig. 1).
TM-1106 (Jan-79) Litho in U.S.A.
Engines - 400 Series
20-05-2 Cylinder Head, Valves, and Camshaft
Engine Repair
Checking Valve Clearance-Continued
Four Cylinder Engine
4
E I
T2284?N
VALVE CLEARANCE SPECIFICATION
Intake and Exhaust Valves
Fig. 2-Four-Cylinder Valve Clearance Adjustment
3
I E
3. Adjust valve clearance on No. 1 and 3 exhaust
valves and No. 1 and 2 intake valves.
4. Rotateflywheel 360 degrees until No.4 piston is
at TOC of its compression stroke.
5. Adjust valve clearance on No. 2 and 4 exhaust
valves and No. 3 and 4 intake valves to the specifica-
tion listed above.
2
E I
1
I E
0.018 In. (0.46 mm)
Six Cylinder Engine
.......
,
II
R 27478NJlj
Fig. 3-Setting "TOC"
1. UseJOE-81 Engine RotationTool Set (A, Fig.3)
to position No. 1 piston at TOC of its compression
stroke.
2. Turnflywheel untiltiming pin engagestiming hole
inflywheel and both valves on No. 1cylinder are in the
up position (rocker arms loose).
OF ENGINE-
432 1
E I lEE I I E
TM-1106 (Jan-79) Litho in U.S.A.
NO. I TDC COMPRESSIONSTROKE
6 5 4 3 2 1
EI IE EI IE EI IE
R 11117
Intake Valves
Exhaust Valves
NO.6 TDC COMPRESSION STROKE
VALVE CLEARANCE SPECIFICATIONS
Fig. 4-Six-Cylinder Valve Clearance Adjustment
Engines - 400 Series
0.018 in. (0.46 mm)
0.028 in. (0.71 mm)
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Engine Repair
Cylinder Head, Valves, and Camshaft 20-05-3
Checking Valve Lift
Measuringvalve liftcan give an indicationofwear to
cam lobes, cam followers, and push rods.
1. Set valve clearance to specifications as pre-
viously indicated.
Fig. 5-Checking Valve Clearance
3. Adjust valve clearance on No.1, 3, and 5 exhaust
valves and No.1, 2, and 4 intake valves (Fig. 5).
4. Rotate flywheel 360 degrees until NO.6 piston is
at "TOG" of its compression stroke, and tool timing pin
engages flywheel hole.
5. Adjustvalve clearance on No.2, 4, and 6 exhaust
valves and No.3, 5, and 6 intake valves to the specifi-
cations listed above.
Fig. 6-Checking Valve Lift (6-Cylinder shown)
2. Place dial indicator on rotator (Fig. 6).
3. Manually turn engine in running direction (coun-
terclockwise) .
4. After rocker arm contacts valve stem, observe
dial indicator reading as valve is moved to full open.
VALVE LIFT NEW PART SPECIFICATIONS
4270
Intake Valves. . . . . . . . . . . . . . .. 0.431 to 0.461 in.
(10.95 to 11.71 mm)
Exhaust Valves 0.427 to 0.457 in.
(10.85 to 11.61 mm)
64040 and 64660
Intake Valves. . . . . . . . . . . . . . .. 0.424 to 0.454 in.
(10.77 to 11.53 mm)
Exhaust Valves. . . . . . . . . . . . .. 0.414 to 0.444 in.
(10.52 to 11.28 mm)
6404T and A; 6466T and A
Intake Valves. .. . . . . . . . . . . . .. 0.412 to 0.442 in.
(10.46 to 11.23 mm)
Exhaust Valves. . . . . . . . . . .. .. 0.413 to 0.443 in.
(10.49 to 11.25 mm)
TM-1106 (Jan-79) Litho in U.S.A.
Engines - 400 Series
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u
20-05-4 Cylinder Head, Valves, and Camshaft Engine Repair
CYLINDER HEAD AND VALVES
Access
1. Disconnect battery ground cables and drain
cooling system (not shown).
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I
Fig. 7-Left Side Removal Steps
(6466A Engine Shown)
2. Remove air cleaner, mufflerand exhaust elbow.
ROCKER ARM ASSEMBLY
Removal
NOTE: 6466T (072864- ) and A (068223-
) engines use a one-piece rocker arm shaft
clampinplace of the Nos. 1and 2 and5 and 6 clamps.
1. Remove rocker arm shaft clamp cap screws.
NOTE: When removing rocker arm shaft compo-
nents, identify for reassembly into original position.
A-End Plug..
B-Oil Holes
Fig. 9-Rocker Arm Shaft Components
(6-Cylinder Shown)
C-Adjusting Screws
3. Remove intercooler ("A" engines) with intake
manifold.
4. Removeturbocharger ("T"and "A"engines) with
exhaust manifold.
Fig.8-Right Side Removal Steps
(6466A Engine Shown)
5. Remove water manifold.
6. Remove fuel lines and leak-off line. Plug open-
ings to prevent contamination.
2. Remove rocker arm shaft end plugs and slide
components from shaft (Fig. 9).
Inspection and Repair
1. Inspect rocker arm shaft for scratches, scores, or
excessive wear at points of rocker arm contact.
NOTE: Wear could indicate weak valve springs,
bent push rods, or loose rocker arm shaft clamps.
2. Be sure that all oil holes are open and clean (B,
Fig. 9).
3. Check rocker arm adjusting nut and screw for
damage (C, Fig. 9).
4. Check for cups or concave wear on ends of
rocker arms where they contact valve tips (A, Fig. 10).
7. Remove fuel injection nozzles.
8. Remove rocker arm cover.
TM-1106 (Jan-79) Litho in U.S.A.
Engines - 400 Series
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