Stop Settling For a Standard "Rebuild"

This remanufactured long block is custom-engineered for demanding construction and earthmoving environments, correcting OEM flaws to eliminate parasitic vibration and catastrophic valve failure for maximum uptime.

Advanced CNC Blueprinting

Engine blocks undergo state-of-the-art CNC machining to achieve perfect dimensions, precise tolerances, and flawless alignment that far surpass factory specifications.

Dynamic Rotational Balancing

The crankshaft, rods, and weight-matched pistons are dynamically balanced to eliminate vibration, minimizing drivetrain stress and extending component life.

Precision Diamond Honing

Cylinder bores are diamond honed to within 0.0001 inches and line honed along a true centerline to ensure optimal piston fit and reduced friction.

Upgraded Industrial Components

Built with premium components, including high-heat exhaust valves to prevent head separation and billet freeze plugs to eliminate cooling system leaks.

WHAT'S INCLUDED?

  • Premium Remanufactured Core: Fully machined engine block, polished crankshaft, connecting rods, and high-flow cylinder head.

  • Upgraded Internal Components: Brand-new pistons, camshaft, pushrods, rockers, and blowout-proof billet freeze plugs.

  • Precision Bearing & Pump Kit: New main, rod, and cam bearings installed alongside a high-volume new oil pump.

  • Complete Sealing System: Premium MLS head gaskets, front gear housing, rear main seal, and upper/lower oil pans.
Full Description

Kawasaki 70Z-III Wheel Loader Long Block Engine

The 6BTA 5.9L industrial engine is the backbone of the Kawasaki 70Z-III, engineered to deliver relentless torque and durability in the most demanding construction and earthmoving environments. Whether you are cycling buckets in a quarry or handling heavy materials on a job site, this remanufactured long block is built to outperform.

 

Key Features and Fixes

  • Vibration Mitigation: A fully balanced rotating assembly ensures your wheel loader runs smoothly and quietly. This precision balancing protects your transmission, hydraulic pumps, and drivetrain components from the parasitic vibration that leads to premature wear.

  • Enhanced Valve Integrity: Features all-new, upgraded exhaust valves designed to withstand the high-cycle heat of heavy-load operations, preventing the valve-head separation that can lead to catastrophic engine failure during critical work hours.

  • Superior Block Protection: Billet freeze plugs are installed to eliminate the common "rot-out" and leaking associated with standard brass or steel plugs, ensuring your cooling system remains pressurized and reliable under heavy load.

 

Machining Process:

At Choate Engineering Performance, we don’t just "overhaul" industrial engines; we remanufacture them to surpass original factory specifications. Our 6BTA units undergo rigorous CNC blueprinting to correct OEM flaws, ensuring the ultimate reliability required for high-uptime construction applications.

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
  • Engine Block
  • Crankshaft
  • Connecting Rods
  • Camshaft
  • New 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

 

Industrial Reliability: 2 Year / 2,000 Hour Warranty

When your machine is on the clock, downtime isn't just an inconvenience, it’s a loss of revenue. At Choate, we stand behind the precision engineering of our Kawasaki 70Z-III engines with a comprehensive 2-Year / 2,000-Hour Warranty.

We understand that construction environments are among the most punishing on equipment. From high-load digging to constant idling and rapid throttle transitions, our warranty is designed to give you total peace of mind. Whether you are a fleet manager or an owner-operator, we ensure your investment is protected against defects in materials and workmanship.

Choate Engineering Industrial engines are covered up 1 year / 2,000 hours, with some limitations.

We also require our customers to follow proper maintenance procedures, replace critical components during installation, and more.

As consideration for the above warranties, the buyer agrees they will take no action, statement, characterization, or implication regarding Choate Engineering Performance that may in any manner be interpreted as disparaging to Choate Engineering Performance or the reputation of Choate Engineering Performance. Any violation of this is a material breach, entitling Choate Engineering Performance to void any warranty.

CHOATE ENGINEERING PERFORMANCE SHALL NOT BE RESPONSIBLE, NOR SHALL IT PAY ANY FREIGHT/SHIPPING CHARGES.

  • All freight and shipping charges are the sole responsibility of the customer, including any customs fees or brokerage fees.
  • Any shipments Choate Engineering Performance arranges for the customer include insurance.
  • In the event the purchased unit is damaged during transportation to or from Choate Engineering Performance, Choate Engineering Performance shall not be responsible for any costs associated with such damage.
  • The repair of such damage is not included under the Limited Warranty; should transportation damage skew the results of the diagnosis such that the findings are that the defect is not covered under the Limited Warranty, Choate Engineering Performance shall incur no liability or responsibility whatsoever.

NOTE:

CALIFORNIA WARNING: Cancer and Reproductive Harm - www.P65Warnings.ca.gov