Dealing with a Blown Engine on a Lull Telehandler

[MikePhua]

The Lull Legacy in Material Handling
Lull telehandlers, originally developed by Lull Engineering Company in the mid-20th century, became known for their unique horizontal boom travel system, which allowed operators to extend and retract loads without moving the chassis. This feature made them ideal for masonry, framing, and material placement in tight construction zones. After being acquired by JLG Industries, Lull models continued to serve in fleets across North America until the brand was retired in the early 2010s.
The most common Lull models, such as the 644E and 944E, featured Cummins or John Deere diesel engines, hydrostatic transmissions, and lift capacities ranging from 6,000 to 10,000 pounds. Their rugged frames and boom design made them popular on job sites, but like any machine, engine failure can bring operations to a halt.
Symptoms and Consequences of a Blown Engine
A “blown” engine typically refers to catastrophic internal failure, such as:

• Piston seizure or rod breakage
  
• Cracked block or head due to overheating
  
• Loss of compression across multiple cylinders
  
• Oil contamination from coolant or fuel
  
• Loud knocking followed by sudden shutdown
  

In one framing crew in Colorado, a Lull telehandler began emitting white smoke and lost power abruptly. The engine was found to have a cracked cylinder head and coolant intrusion into the oil pan. The machine had been running without a functioning temperature gauge, and the operator had no warning before failure.
Terminology Notes

• Telehandler: A telescopic handler used for lifting and placing materials, often with a boom-mounted fork or bucket.
  
• Horizontal Boom Travel: A feature allowing the boom to slide forward and backward without tilting, unique to Lull machines.
  
• Compression Loss: A drop in cylinder pressure due to valve, ring, or gasket failure.
  
• Hydrostatic Transmission: A drive system using hydraulic fluid to transfer power from engine to wheels.
  
• Coolant Intrusion: The entry of coolant into the oil system, often due to gasket or head failure.
  

Repair vs Replacement Considerations
When facing a blown engine, owners must weigh the cost and feasibility of repair versus replacement. Factors include:

• Availability of compatible engines (e.g., Cummins 4BT, John Deere 4045)
  
• Condition of the rest of the machine (hydraulics, frame, tires)
  
• Labor costs for engine swap or rebuild
  
• Downtime impact on job schedules
  
• Resale value after repair
  

Typical options:

• Rebuild the existing engine if the block is intact
  
• Replace with a remanufactured engine from a certified supplier
  
• Retrofit with a newer engine model, requiring mount and harness modifications
  
• Sell the unit as-is for parts or scrap
  

In one roofing company in Ontario, a Lull 644E with a seized engine was retrofitted with a remanufactured Cummins 4BT. The swap took 40 labor hours and cost $8,500, but the machine returned to service and completed a multi-unit housing project without further issues.
Steps for Engine Removal and Installation
Removing a Lull engine involves:

• Disconnecting battery and isolating electrical systems
  
• Draining coolant and hydraulic fluid
  
• Removing hood, side panels, and counterweights
  
• Disconnecting fuel lines, throttle linkage, and exhaust
  
• Unbolting engine mounts and lifting with a crane or hoist
  
• Inspecting bell housing and flywheel for wear
  
• Installing replacement engine and aligning mounts
  
• Reconnecting all systems and testing under load
  

Safety tips:

• Use rated lifting equipment and cribbing
  
• Label all wiring and hoses during disassembly
  
• Replace all fluids and filters before startup
  
• Torque bolts to manufacturer specifications
  
• Monitor temperature and oil pressure during first run
  

Preventive Measures to Avoid Engine Failure
To extend engine life:

• Check coolant levels and temperature gauges daily
  
• Change oil and filters every 250 hours or quarterly
  
• Inspect belts, hoses, and radiator fins for wear
  
• Use fuel additives to prevent injector fouling
  
• Monitor exhaust color and engine sound for early warning signs
  

In one fleet in Arizona, installing aftermarket temperature alarms and conducting monthly fluid analysis reduced engine failures by 70% and extended average engine life by 2,000 hours.
Final Thoughts
A blown engine on a Lull telehandler is a serious setback, but not the end of the machine’s usefulness. With careful assessment, proper sourcing, and skilled labor, many units can be revived and returned to productive service. Whether rebuilding or replacing, the key is understanding the machine’s value and the role it plays in your operation. In the world of material handling, resilience isn’t just mechanical—it’s a mindset.