Restoring Ignition Functionality on the Buda HP217 with Delco Remy 629N Distributor

[MikePhua]

The Buda HP217 and Its Legacy in Trenching Equipment
The Buda HP217 engine was part of a series of industrial powerplants manufactured by Buda Engine Co., a Chicago-based company founded in the early 20th century. Known for their robust cast-iron blocks and long-stroke torque characteristics, Buda engines powered everything from generators to trenchers and cranes. By the mid-century, Buda had been absorbed into Allis-Chalmers, but its engines continued to serve in legacy equipment across North America.
The HP217 was commonly installed in Cleveland trenchers—machines used for laying pipe and cable in municipal and agricultural infrastructure. These trenchers relied on mechanical simplicity and rugged components, including the Delco Remy 629N distributor, a key part of the ignition system.
Terminology Annotation

• Distributor: A rotating electrical device that routes high-voltage current from the ignition coil to the spark plugs in the correct firing order.
  
• Cap and Rotor: Components inside the distributor that transfer current to plug wires.
  
• Tang Drive: A flat-blade coupling used to connect the distributor shaft to the camshaft.
  
• Gear Drive: A toothed coupling that synchronizes distributor rotation with engine timing.
  

Common Failure Modes and Field Diagnosis
In aging trenchers, the distributor often becomes a point of failure due to exposure to moisture, vibration, and corrosion. When water infiltrates the cap, it can short the rotor, pit the terminals, and destroy the internal contacts. In the case of the 629N, once the cap is compromised, the distributor may be rendered inoperable.
Symptoms of distributor failure include:

• No spark at the plugs
  
• Engine cranks but does not fire
  
• Visible rust or carbon tracking inside the cap
  
• Rotor wobble or shaft play
  
• Burnt smell or melted insulation
  

In one Michigan restoration project, a Buda-powered trencher sat idle for years before being revived. Upon inspection, the distributor cap was found filled with rust flakes and moisture. The rotor had fused to the shaft, and the points were corroded beyond recognition.
Replacement Challenges and Compatibility Questions
Finding a direct replacement for the Delco Remy 629N can be difficult. While similar models like the 629H may appear compatible, differences in drive type—tang versus gear—can prevent proper installation. Additionally, internal components such as advance weights, breaker plates, and shaft lengths may vary.
Recommendations for sourcing and verification:

• Compare distributor tags and casting numbers
  
• Measure shaft diameter and drive depth
  
• Verify rotation direction and firing order
  
• Inspect mounting flange and bolt pattern
  
• Cross-reference with Delco Remy service manuals or vintage parts catalogs
  

In one Kansas repair shop, a technician successfully adapted a 629H distributor by machining a custom gear adapter and modifying the advance curve to match the Buda engine’s timing profile.
Restoration Techniques and Preventive Measures
If the original distributor is salvageable, restoration may be possible through:

• Complete disassembly and degreasing
  
• Soaking in rust remover (e.g., phosphoric acid or electrolysis bath)
  
• Replacing points, condenser, rotor, and cap
  
• Lubricating bushings and checking shaft endplay
  
• Testing coil resistance and spark output
  

For severely damaged units, consider converting to electronic ignition using a Pertronix-style module, provided the distributor body is intact. This eliminates points and improves reliability.
Preventive steps include:

• Installing a weatherproof cap seal
  
• Using dielectric grease on terminals
  
• Storing the machine under cover or indoors
  
• Running the engine periodically to prevent moisture buildup
  

In one Illinois riverfront operation, a trencher’s distributor was protected using a custom rubber boot and silica gel packs inside the cap. The machine ran reliably through three seasons without electrical faults.
Final Thoughts
The Buda HP217 and its Delco Remy 629N distributor represent a bygone era of mechanical simplicity. While parts may be scarce, ingenuity and cross-referencing can bring these machines back to life. Whether trenching for irrigation or restoring vintage iron, the ignition system is the heartbeat—and when the distributor sparks true, the engine follows.
In legacy equipment, every rotation counts. And when the spark returns, so does the machine’s purpose.