JE Ultra Series Forged Piston Kit for Honda Civic Type R K20C 86mm - 361278

Honda K20C Turbo | 10.0:1 | 86mm Bore | Forged 2618 | FSR | 22mm Pins | Thermal Crown | Set of 4

Building a Honda Civic Type R engine that can handle a bigger turbocharger, increased boost, and more demanding track use? The JE Pistons Ultra Series Forged Piston Kit, part number 361278, is designed for the K20C turbocharged four-cylinder platform, giving performance builders a premium alternative to factory-style pistons. Whether you're rebuilding after piston damage or assembling a stronger short block for future power upgrades, these American-made forged pistons provide the strength-oriented construction and advanced ring-sealing features needed for serious turbocharged performance.

With an 86.00mm standard bore and 10.0:1 nominal compression ratio, this kit maintains the intended K20C engine geometry while adding JE's Aligned Grain Flow forging technology, lightweight FSR piston design, thermal-barrier crown coating, and lateral gas ports. The pistons also feature coated skirts and heavy-duty 9310 steel wrist pins. Combined with the included JE Pro Seal piston rings and retaining locks, this set provides the core components for a carefully engineered four-cylinder performance build.

Key Features & Specifications:

Kit Includes:

• 4 x JE Ultra Series 2618 Forged Aluminum FSR Pistons

• JE Pro Seal Premium Piston Ring Set

• 4 x 9310 Nickel Carbon Steel Alloy Wrist Pins

• Wrist Pin Retaining Locks

About the JE Ultra Series Honda K20C Pistons

Built for Serious Turbocharged Honda Performance

The Honda K20C has quickly become one of the most exciting modern four-cylinder engines to modify. With strong turbocharged performance right from the factory, it's a natural starting point for enthusiasts looking to increase power, improve track capability, or build a more aggressive weekend car.

Once you're planning significantly greater cylinder pressures, though, the rotating assembly needs to match the rest of the build. JE's Ultra Series pistons are designed for these demanding applications, using forged 2618 aluminum and advanced piston technology to support engines operating under elevated boost and sustained load.

The 10.0:1 nominal compression configuration also allows builders to retain the intended compression characteristics of this piston design while benefiting from its upgraded construction and specialized features.

Aligned Grain Flow Forging and FSR Design

JE's proprietary Aligned Grain Flow forging process is engineered to enhance tensile strength, particularly for high-cylinder-pressure performance engines.

The Forged Side Relief design uses a narrower piston skirt to help reduce friction and unnecessary reciprocating weight. The result is a forged piston configuration developed specifically around performance engine requirements.

Together, these features make the Ultra Series well suited to a properly engineered K20C build with more demanding turbocharger and operating goals.

Advanced Ring Sealing Under Boost

When a turbocharged engine is operating under heavy load, maintaining effective piston ring sealing becomes especially important.

These pistons feature lateral gas ports that create a path for combustion pressure to reach the back of the top compression ring. This helps promote ring sealing during high-pressure operation.

JE also incorporates accumulator grooves between the top and second compression rings. The additional volume helps manage gases passing the top ring, reducing inter-ring pressure and helping minimize ring flutter.

For a performance K20C that regularly sees high boost and elevated engine speeds, these features address important aspects of combustion sealing.

Thermal Crown Protection and Coated Skirts

The Ultra Series thermal crown coating is designed to reflect heat toward the combustion chamber and reduce heat transfer into the piston body. This helps manage the thermal demands placed on the pistons during aggressive operation.

JE's skirt coating reduces friction and wear between the piston skirts and cylinder walls while helping limit operating noise.

These coatings add practical value for performance engines that may see everything from normal street driving to demanding track sessions.

Premium Wrist Pins and Piston Hardware

Part 361278 uses 9310 nickel carbon steel alloy wrist pins with a substantial 0.230-inch wall thickness, providing a premium pin construction for demanding engine applications.

The pin bores are precision-honed for controlled wrist pin clearance. JE identifies typical pin-fit clearances of 0.0003 to 0.0010 inches, with the final assembly measurements established by the engine builder.

With premium JE Pro Seal rings and retaining locks included, this package provides the main piston components needed for an upgraded K20C short block.

Whether you're repairing a damaged Civic Type R engine or preparing for a more capable turbocharged build, JE Ultra Series 361278 combines advanced forging technology, thermal management, and ring-sealing features in one four-piston kit.

Fitment & Installation Notes:

• Honda Civic Type R: Designed for compatible K20C turbocharged engine applications, including the K20C1 platform.

• Honda K20C Series: Verify the exact engine variant, cylinder head, connecting rods, and piston geometry before ordering.

• Engine Requirement: Honda K20C turbocharged four-cylinder.

• Bore Requirement: 86.00mm finished cylinder bore.

• Bore Configuration: Standard bore.

• Compression Ratio: Nominal 10.0:1 with the specified K20C engine geometry. Final compression depends on cylinder head volume, gasket thickness, and deck clearance.

• Piston Configuration: -0.27cc crown volume and 1.260-inch compression height.

• Wrist Pin Diameter: 0.866 in. (22mm nominal).

• Connecting Rod Compatibility: Confirm the rod small-end bore and wrist pin fit before assembly. Factory connecting rods may require machining to accommodate the supplied pins.

• Cylinder Preparation: Measure and finish the cylinders to JE's specified piston-to-wall clearance.

• Piston Ring Installation: Check and set ring end gaps according to JE's requirements for the intended boost, fuel, and operating conditions.

• Piston-to-Valve Clearance: Verify clearance during engine assembly, especially with modified camshafts, cylinder heads, or valve timing.

• Engine Tuning: Proper fuel delivery, ignition calibration, boost control, and supporting modifications are essential to the completed engine build.

• Horsepower Rating: No specific horsepower limit is published for part 361278. Engine capability depends on the complete rotating assembly, machining, supporting components, and tuning.

The JE Ultra Series 361278 piston kit delivers forged 2618 construction, a lightweight FSR design, advanced ring-sealing technology, thermal protection, and upgraded wrist pins for builders pursuing serious Honda K20C turbocharged performance.