John Deere 4045 / 6068 — Checking and Adjusting Valve Clearance
Adjustments · Cylinder head / valve train
For the John Deere 4045 / 6068, from the John Deere operator's manual.
Applies to: John Deere 4045, John Deere 6068
Before you start
- Valve clearance MUST BE checked and adjusted with engine COLD.
- Always disconnect NEGATIVE (—) battery terminal to prevent accidental starting.
Procedure
- Disconnect NEGATIVE (—) battery terminal.
- Remove rocker arm cover and crankcase ventilator tube.
- Remove plugs from timing/rotation hole and timing pin hole.
- Rotate flywheel in running direction until No. 1 cylinder at TDC compression.
- Insert timing pin in flywheel.
- Loosen jam nut on rocker arm adjusting screw.
- Turn adjusting screw until feeler gauge slips with slight drag; tighten jam nut.
- Recheck clearance after tightening jam nut; install rocker arm cover and reconnect battery.
Tools required
- JDE83 or JDG820 Flywheel Turning Tool Amazon
- JDG1571 or JDE81-4 Timing Pin Amazon
- Feeler gauge Amazon
- JDG966 Crankshaft Front/Rear Rotation Adapter Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Intake valve clearance (engine cold) 0.36 mm (0.014 in.)
- Exhaust valve clearance (engine cold) 0.46 mm (0.018 in.)
- Rocker arm adjusting screw jam nut torque 27 N·m (20 lb-ft)
Full service-parts list: John Deere 4045 →, John Deere 6068 →
Source: John Deere operator's manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.