Kawasaki 70Z-IV Wheel Loader Long Block Diesel Crate Engine Choate Performance

Kawasaki 70Z-IV Wheel Loader Long Block Engine

The B5.9-C industrial engine is the legendary workhorse powering the Kawasaki 70Z-IV. Known for its mechanical simplicity and relentless torque, this engine is designed to handle the high-stress cycles of earthmoving and material handling. Our remanufactured long block takes this proven platform and applies modern precision machining to eliminate factory weak points and maximize your machine's uptime.

Key Features and Fixes

• Vibration Mitigation: A fully balanced rotating assembly ensures your wheel loader operates with minimal harmonic distortion. This protects your hydraulic pumps, transmission, and mounting hardware from the steady vibration that leads to component fatigue and costly leaks.

• Enhanced Valve Integrity: We install all-new, upgraded exhaust valves designed to withstand the high-heat cycles of constant digging and loading. This prevents valve-head separation, a common cause of catastrophic failure in heavy-duty industrial applications.

• Reliable Cooling Integrity: Billet freeze plugs are installed to replace the standard stamped steel or brass plugs. This prevents the "blow-out" or corrosion-related leaks that can lead to overheating and engine seizure in the middle of a shift.

• Optimized for Load: Every aspect of this build is engineered to handle the rapid throttle transitions and high-torque demands characteristic of the Kawasaki 70Z-IV’s duty cycle.

Machining Process:

At Choate Engineering Performance, we don’t just "fix" engines; we remanufacture the B5.9-C to surpass original factory specifications using advanced CNC blueprinting.

Engine Block Machining:

Each of our engine blocks are CNC blueprint machined using state-of-the-art CNC machines. This process ensures perfect dimensions, precise tolerances, and optimal alignment. This starts with decking the surface of the block to achieve the necessary flatness and smoothness (Ra 30 or better) required for flawless sealing with MLS head gaskets. The cylinders are then diamond honed to an extremely tight tolerance to match the piston diameter (within the nearest 0.0001 inch). Following honing, the main bearing bores are line honed to establish a true, straight centerline for the crankshaft. Finally, the cylinder bores are bored to a true 90 degree angle from the crankshaft centerline.

Cylinder Head Machining:

Our cylinder heads are fully machined and enhanced in-house to improve airflow and reliability. Each head is first magnafluxed and pressure tested to ensure they are free of any cracks or leaks. The surface is then precision decked to an extremely smooth finish, guaranteeing the necessary flatness for a perfect seal with MLS head gaskets. Internally, the valve seats are machined to optimize airflow and prevent common failures, and the entire valve train geometry is blueprinted to specific tolerances to reduce lifter preload and prolong component life.

Rotational Assembly Balancing:

The balancing of the rotational assembly is crucial for eliminating vibration and maximizing engine longevity. This precision work involves checking and correcting the balance of the crankshaft, connecting rods, and pistons. The crankshaft is thoroughly checked for run-out and inspected for fatigue before being polished and ground to strict concentricity tolerances (0.0005 or less) to ensure the new bearings receive the best possible surface. Rods are inspected and conditioned, and all bearing clearances checked to ensure proper fitment with the new bearings. Each of the pistons, rings, and pin retainers are meticulously weight matched (to a tolerance of 2 grams or less) prior to crank balancing. Then the entire assembly is dynamically balanced on specialized equipment. This ensures that the engine runs smoothly, minimizing stress on the bearings, and extends the overall life of the components.

Components and Parts:

Engine Core Components

• Cylinder Block
• Crankshaft
• Connecting Rods
• Camshaft
• Pistons
• Reman Cylinder Head
• Pushrods
• New Main Bearings
• New Rod Bearings
• New Cam Bearings
• Main Bolts
• Head Studs
• Rockers
• Billet Freeze Plugs
• New Oil Pump
• Upper Oil Pan
• Lower Oil Pan

Gaskets and Seals

• New Head Gaskets
• Rear Main Seal
• Front Gear Housing

Cylinder Head Components

• New Valve Guides
• New Socket Plug
• New Oversized Valve Seats
• New Threaded Plugs

Construction-Grade Confidence: 2 Year / 2,000 Hour Warranty

In the construction world, if the loader isn't moving, the job isn't making money. At Choate, we stand behind the durability of our B5.9-C Long Block Engines with a comprehensive 2-Year / 2,000-Hour Warranty.

We understand that the Kawasaki 70Z-IV is often the centerpiece of a fleet, subjected to dust, heat, and heavy loads. Our warranty is built to provide peace of mind to owner-operators and fleet managers alike, ensuring that your investment is protected by the highest standards of American engineering and craftsmanship.