Restoring and Timing the Injection System on the IH 260A Backhoe

[MikePhua]

The IH 260A and Its Place in Construction History
The International Harvester 260A backhoe loader was part of a generation of rugged, mechanically straightforward machines built during the 1970s and early 1980s. IH, founded in 1902, was a major player in agricultural and industrial equipment, and the 260A was designed to compete with models like the Ford 550 and Case 580B. With a robust frame, mechanical controls, and a diesel powerplant, the 260A was favored by municipalities and small contractors for its reliability and ease of repair.
Though exact production numbers are hard to pin down, IH sold tens of thousands of backhoes globally before merging into Navistar in the mid-1980s. The 260A typically came equipped with a D-239 diesel engine and a Bosch VA mechanical injection pump, a setup known for its durability but requiring precise timing to operate efficiently.
Terminology Annotation

• Injection Pump: A mechanical device that pressurizes and delivers fuel to the engine’s cylinders at precisely timed intervals.
  
• BTDC (Before Top Dead Center): A measurement indicating how many degrees of crankshaft rotation before the piston reaches its highest point that fuel injection begins.
  
• Timing Pointer: A fixed reference mark on the pump or engine used to align internal timing marks during setup.
  
• Flywheel Timing Marks: Engraved or stamped indicators on the flywheel used to verify engine timing relative to piston position.
  

Timing the Bosch VA Pump on the D-239 Engine
Correct timing of the Bosch VA pump is essential for cold starts, fuel efficiency, and engine longevity. The process involves aligning internal pump marks with the engine’s crankshaft position. On the D-239 engine, the standard injection timing is typically set at 19 degrees BTDC.
To time the pump:

• Remove the side cover plate on the Bosch VA pump and allow residual fuel to drain.
  
• Inside, locate the timing pointer—a small flat tab that aligns with a scribed line on the rotating internal cam ring.
  
• Rotate the engine manually using a barring tool until the scribed line aligns perfectly with the pointer.
  
• Check the flywheel for the 19-degree BTDC mark and confirm alignment with the timing window.
  
• If the pump is being removed, mark the flange and housing to preserve orientation during reinstallation.
  

This method ensures that the pump is synchronized with the engine’s compression stroke, delivering fuel at the optimal moment for combustion.
Common Pitfalls and Practical Advice
Several issues can arise during pump timing:

• Misalignment due to worn timing gears or incorrect flywheel markings
  
• Difficulty rotating the engine manually if the decompression lever is not engaged
  
• Fuel contamination obscuring internal marks
  
• Incorrect reinstallation angle causing delayed or premature injection
  

To avoid these problems:

• Clean the pump thoroughly before inspection
  
• Use a mirror and flashlight to verify internal marks
  
• Always rotate the engine in its normal direction of travel
  
• Replace the side cover gasket to prevent leaks after reassembly
  

A Story from the Field
In 2022, a restoration enthusiast in North Carolina acquired a neglected IH 260A from a county auction. The machine had sat for years, and the injection pump was seized. After rebuilding the pump and reinstalling it, the engine refused to start. A retired technician advised checking the internal timing marks. Upon inspection, the pump had been installed 180 degrees out of phase. After correcting the alignment and setting the timing to 19 degrees BTDC, the engine fired immediately. The machine went on to clear brush and dig trenches for a local community garden.
Industry Trends and Legacy Support
While IH no longer manufactures construction equipment, parts for the D-239 engine and Bosch VA pump remain available through aftermarket suppliers and diesel specialists. In 2024, several vintage equipment forums began compiling digital manuals and timing guides for legacy machines like the 260A, helping owners preserve and operate these classics.
Bosch VA pumps are still used in agricultural engines and stationary power units, and rebuild kits—including plungers, delivery valves, and seals—are widely available. Timing tools and barring sockets for the D-series engines can be sourced from tractor restoration suppliers.
Preventative Maintenance Recommendations
To keep the injection system in peak condition:

• Replace fuel filters every 250 hours
  
• Use clean, low-sulfur diesel to reduce injector fouling
  
• Inspect timing marks annually during valve lash adjustment
  
• Lubricate pump linkages and check for wear
  
• Drain water separators regularly to prevent corrosion
  

Conclusion
The IH 260A backhoe remains a testament to mechanical simplicity and industrial durability. Proper timing of its Bosch VA injection pump is critical to performance and reliability. With careful alignment, clean fuel, and routine inspection, these machines can continue serving for decades. Whether restoring a vintage unit or maintaining a working fleet, understanding the timing process is key to unlocking the full potential of the D-239 engine.