Swapping a 188 Diesel into a Case CK Loader Backhoe

[MikePhua]

The Case CK Series and Its Engine Legacy
The Case CK loader backhoe series, produced during the 1960s and 1970s, was a workhorse of its time. Known for mechanical simplicity and rugged steel construction, these machines were widely used in municipal work, farm maintenance, and small-scale excavation. Originally equipped with gasoline or early diesel engines, many CK units have outlived their factory powerplants, prompting owners to consider engine swaps to extend their service life.
One popular candidate for replacement is the Case 188 diesel engine—a 3.1-liter, four-cylinder powerplant developed by Case in the 1970s. The 188 was used in a range of equipment including the 580B and 580C backhoes, as well as agricultural tractors. Its reputation for torque, cold-start reliability, and parts availability makes it a logical choice for retrofitting into older CK frames.
Terminology Notes

• CK (Construction King): Case’s branding for its loader backhoe series.
  
• 188 Diesel: A naturally aspirated four-cylinder engine rated around 60 horsepower.
  
• Bellhousing: The housing that connects the engine to the transmission.
  
• Flywheel Ring Gear: A toothed ring used to engage the starter motor.
  

Compatibility and Mounting Considerations
Swapping a 188 diesel into a CK frame requires attention to several mechanical interfaces:

• Engine mounts may need to be relocated or modified depending on the original engine configuration.
  
• The bellhousing bolt pattern must match the transmission flange. Some CK units used a Borg-Warner transmission, while others had Case-specific gearboxes.
  
• The flywheel ring gear must align with the starter motor. If mismatched, the starter may not engage properly.
  
• The throttle linkage and fuel shutoff must be adapted to the diesel governor system.
  

A technician in Iowa retrofitted a 188 into his CK loader by fabricating custom mounts and modifying the throttle linkage using parts from a Case 580B. He reported improved fuel economy and better cold-weather starts compared to the original gas engine.
Cooling and Exhaust System Adjustments
The 188 diesel has different cooling requirements than older gasoline engines:

• Radiator capacity must match the diesel’s thermal output. A 3-core radiator is recommended.
  
• The fan shroud may need trimming or repositioning to accommodate the diesel fan.
  
• Exhaust routing must clear the loader arms and frame. Many swaps use a vertical stack or side-exit muffler.
  

A contractor in Michigan installed a vertical exhaust stack with a rain cap to prevent water intrusion during outdoor storage. He also added a coolant overflow tank to manage thermal expansion during long grading sessions.
Electrical and Fuel System Integration
Diesel engines require different electrical and fuel setups:

• The ignition system is replaced with a fuel solenoid and glow plug circuit.
  
• A key switch with a spring-return glow plug position is ideal.
  
• Fuel lines must be upgraded to handle diesel viscosity and pressure.
  
• A lift pump may be needed if the tank sits below the injection pump.
  

A farmer in Nebraska wired his glow plugs to a momentary toggle switch and installed a marine-grade fuel filter with a water separator. His CK started reliably even after sitting idle for weeks.
Recommendations for a Successful Swap

• Use OEM or aftermarket engine mounts rated for vibration damping
  
• Verify flywheel and starter compatibility before installation
  
• Upgrade the cooling system with a high-flow water pump and matched radiator
  
• Install a fuel shutoff solenoid wired to the key switch
  
• Replace all fuel lines with diesel-rated hose and clamps
  
• Use a voltmeter to confirm glow plug voltage during cold starts
  

Conclusion
Swapping a Case 188 diesel into an old CK loader backhoe is a practical and rewarding upgrade that can breathe new life into a classic machine. With careful planning, modest fabrication, and attention to compatibility, the result is a reliable, fuel-efficient workhorse ready for another generation of digging, lifting, and hauling. In a world of computerized equipment, the CK with a 188 diesel stands as a tribute to mechanical resilience and hands-on ingenuity.