John Deere PowerTech 6.8L 6068 Natural Gas Engines Technical Manual (CTM146 and CTM113)

Table of Contents 

SECTION —Repair
Group 00—Safety
Group 01—General Information
Group 02—Fuels, Lubricants, and Coolant
Group 03—Engine Mounting
INDX Group 04—Engine Rebuild Guide
Group 05—Cylinder Head and Valves
Group 10—Cylinder Block, Liners, Pistons, and Rods
Group 15—Crankshaft, Main Bearings, and Flywheel
Group 16—Camshaft and Timing Gear Train
Group 20—Lubrication System
Group 25—Cooling System
Group 30—Air Intake and Exhaust System
Group 35—Fuel Supply System
Group 40—Starting and Charging System
Group 45—Electronic Engine Controls
Group 50—Miscellaneous Accessories
Group 99—Dealer Fabricated Tools

Information is organized in groups for the various components requiring service instruction. At the beginning of each group are summary listings of service tools and other materials needed to do the job.

Specifications and torques are also listed at the beginning of each group. Component Technical Manuals are concise service guides for specific components. Component technical manuals are written as stand-alone manuals covering multiple machine applications. Refer to the companion manual, CTM113 for diagnostic and testing of 6.8 L engine systems,
including electronic engine controls. Theory of operation for various engine systems is also covered in CTM113 (sold separately). Fundamental service information is available from other sources covering basic theory of operation, fundamentals of troubleshooting, general maintenance, and basic type of failures and their causes.

Use this component technical manual in conjunction with the vehicle technical manual. An application listing in the introduction identifies product-model/component type-model relationship. See the vehicle technical manual for information on component removal and installation, and gaining access to the components. This manual contains the necessary instructions for removal, repair and installation of various engine components.

This component technical manual (CTM) covers the recommended repair procedure for 6068 HFN, 6.8 L (414 cu. in.) Compressed Natural Gas (CNG) engines produced in Dubuque, Iowa. Before beginning repair of an engine, clean the engine and mount on a repair stand. (See Group 03)—Engine Mounting.) Direction of engine crankshaft rotation in this manual is referenced facing the flywheel looking toward the vibration damper. Front of engine is vibration damper end. Some components of this engine may be serviced without removing the engine from the machine. Refer to the specific machine technical manuals for information on components that can be serviced without removing the engine from the machine and for engine removal and installation procedures. Read each repair procedure completely before performing any service.