How to Install OS Giken Twin Plate Clutch on Nissan Skyline GTR
Upgrading the transmission and drivetrain of a Nissan Skyline GTR with an OS Giken Twin Plate Clutch can transform street usability and high-rpm performance. This guide dives into the practical steps, required tools, and critical checks to ensure a reliable installation that complements the car’s renowned handling and power. The Twin Plate setup is designed to handle higher torque levels while offering smoother engagement compared to conventional single-plate clutches, making it a popular choice for tuned Skylines that see both track duty and daily use.
Pre-Installation Planning and Compatibility
Before starting the installation, a thorough plan reduces the risk of misfit and drivetrain issues. The Skyline GTR’s manual transmission and bell housing have evolved across model years, so confirming compatibility with the OS Giken unit is essential. Gather the following: a clean workspace, a torque wrench with the appropriate range, metric socket set, screwdrivers, pliers, snap ring pliers, and a clutch alignment tool. A service manual for your specific Skyline generation (R32, R33, or R34) provides the critical torque specs and sequence for flywheel bolts, pressure plate bolts, and release bearing attachments. Properly rated gloves and eye protection are recommended for safety during disassembly and reassembly.
OS Giken Twin Plate Clutches are engineered to fit standard flywheels with specific bolt patterns and pilot bore sizes. Check the clutch kit contents for a pilot bearing or bushing, a spline-compatible release bearing, and any shims supplied for minor clearance adjustments. If the kit requires a modified flywheel or a specific alignment procedure, the installation manual will detail these steps. It is common for a performance clutch to require a slight modification to the flywheel surface or a new pilot bearing if the original shows wear. In all cases, starting with a clean flywheel surface and inspecting the crankshaft end play helps avoid chatter or misalignment after installation.
Transmission and Torque Considerations
The OS Giken Twin Plate is designed to tolerate higher torque than a factory unit. When pairing with a Skyline’s engine and tuner profile, it’s vital to size the clutch to the expected engine torque and rpm range. If the engine is tuned for peak torque at higher RPMs, ensure the clutch’s clamp load and pedal effort remain manageable for street use. The Twin Plate’s dual friction discs are engineered to provide smoother engagement, but this can result in a slightly different pedal feel. For aggressive launches or track use, the clutch can be dialed in with a firmer pressure plate preload, but this adjustment should be performed within the kit’s specified range to avoid premature wear or slippage. Consider also the flywheel’s condition; a lightly resurfaced or replaced flywheel can contribute to even engagement and improved friction surface longevity.
Disassembly: Accessing the Clutch and Flywheel
Begin with the vehicle securely supported on jack stands and ensure the transmission is in neutral. Disconnect the battery to prevent accidental engagement of electrical components during the procedure. Remove wheels if necessary to access the lower bell housing bolts and the starter. Drain the transmission fluid if you will be accessing the main input shaft and bell housing more easily. The goal of the disassembly phase is to expose the pressure plate bolts, the release bearing, and the flywheel mounting bolts without damaging surrounding components.
Carefully detach the slave cylinder line if your Skyline uses a hydraulic release mechanism. The release fork and the release bearing can then be removed in a controlled manner. It is helpful to label or photograph the arrangement of springs, dowels, and fasteners to ensure accurate reassembly. When inspecting the flywheel surface, look for hot spots, cracking, or grooves that indicate uneven friction surface wear. A clean, uniform surface is essential for consistent clutch engagement and longevity.
Pilot Bearing, Release Bearing, and Alignment
With the clutch components removed, inspect the pilot bearing or bushing for wear. A worn pilot bearing can cause concentric runout, misalignment, and noise during engagement. Replace if there is noticeable play or roughness. The release bearing should rotate smoothly without binding when slid along the input shaft. Installing a fresh release bearing reduces the risk of chatter and ensures even disc wear across engagements. During reassembly, use the provided alignment tool to center the pressure plate assembly on the flywheel. A misaligned assembly can lead to uneven disc wear and clutch chatter after installation.
Installing the OS Giken Twin Plate Clutch
Position the OS Giken Twin Plate clutch onto the flywheel with the alignment tool inserted through the transmission input shaft. The alignment tool helps center the pressure plate and friction discs relative to the flywheel surface, ensuring a clean engagement. Start by hand-tightening the pressure plate bolts in a crisscross pattern to draw the assembly evenly against the flywheel. Then, use a torque wrench and tighten bolts to the manufacturer’s specified sequence and torque. The correct sequence prevents warping and ensures even clamping force across the friction surfaces. If the kit includes anti-squeal shims or alignment spacers, install them as directed to achieve the proper clearance between the clutch and pressure plate.
With a twin-plate setup, the load path during engagement differs from a single-plate design. The result is a more stable engagement, particularly under higher torque, but it can require a precise bedding-in procedure. Bedding-in involves gradually applying torque and pedal pressure to seat the friction surfaces evenly. This process often takes several heat cycles and controlled driving sessions to prevent glazing the friction material and to promote uniform wear. Follow OS Giken’s bedding-in guidelines, which typically include a series of controlled accelerations and decelerations at moderate speeds, allowing the discs to seat without shock loading the drivetrain.
Hydraulic or Mechanical Release: Ensuring Proper Actuation
Depending on the Skyline’s transmission model, the release mechanism can be hydraulic or mechanical. For hydraulic systems, ensure the master and slave cylinders are free of leaks and bleed the system to remove air. A soft pedal feel can indicate air in the line or low fluid. For mechanical linkages, inspect the fork, clip retaining rings, and the pushrod for smooth operation. Any stiffness or binding should be addressed before you complete the installation, as a stiff release can cause incomplete disengagement and gear grinding during shifting.
Reassembly and System Validation
Reassembly proceeds in reverse order of disassembly. Lower the transmission carefully into place, aligning the input shaft with the pilot bearing. Continue with the bell housing bolts, ensuring they are torqued to spec with the correct sequence. Reconnect the transmission crossmember and the driveshaft, then refill the transmission with the appropriate fluid. Start the engine, and perform a careful check of clutch engagement at the pedal’s midpoint. If the engagement feels abrupt or the vehicle stalls, re-check alignment, pedal height, and the release bearing operation. A first test drive at light throttle confirms smooth engagement and prevents sudden loads that could jeopardize the gearset or the new clutch surface.
Driveability, Noise, and Heat Management
Post-installation drive tests should include varied speeds to evaluate engagement smoothness, gear selection ease, and any abnormal noises. A properly bedded twin-plate system often shows reduced pedal force compared to some aftermarket single-plate options, thanks to optimized lever mechanics and friction surface design. However, under high-load conditions at the track, you may notice more heat generation in the clutch area. Adequate cooling for the area above the transaxle and ensuring the drain paths remain clear helps prevent heat soak that can lead to clutch slip or reduced performance. Routine inspection of the clutch housing and surrounding components helps catch early signs of heat-related wear before it manifests as performance loss.
Performance Integration: Drivetrain Synergy and Upgrade Path
The Nissan Skyline GTR drivetrain is well-regarded for its balance of power and traction. When the Twin Plate clutch is coupled with a tuned engine, upgraded intake and exhaust, and an optimized drivetrain alignment, the car can achieve faster 0-60 mph times and more consistent lap times. It is important to consider ancillary upgrades such as a reinforced release bearing housing or collar to reduce flex under high torque. Many enthusiasts also opt for a lightweight flywheel to further reduce rotational mass, provided the clutch kit and flywheel work harmoniously. If you plan on aggressive track use, consider a differential upgrade and upgraded transmission mounts to minimize drivetrain flex and improve shift feel under load. Collectively, these enhancements help the car deliver reliable, repeatable performance while preserving drivability on public roads.
Maintenance and Longevity Tips
Regular inspection of the clutch and related components extends service life. Check for oil leaks around the bell housing, as transmission oil can degrade clutch materials over time. Ensure the slave cylinder seal remains intact and that the clutch hydraulic lines are free from cracks or kinks. When changing engine oil or performing routine maintenance, inspect the flywheel surface for glazing or hot spots, and replace or resurface if needed. Periodic checks of the release bearing alignment and the clutch pedal feel help maintain consistent engagement characteristics and reduce the likelihood of unexpected slip during aggressive driving.
Common Pitfalls and How to Avoid Them
One common issue is incorrect bolt torque or uneven tightening of the pressure plate. This can cause warping of the pressure plate or uneven contact with the friction surface. Always tighten in a cross pattern and use the manufacturer’s torque sequence. Another pitfall is misalignment due to an insufficiently seated pilot bearing. This creates noise and vibration that can be mistaken for other drivetrain problems. Ensuring the pilot bearing is properly seated and the alignment tool is used during installation minimizes this risk. Finally, avoid rushing the bedding-in process. A proper bedding-in sequence helps achieve even friction surface wear and a longer service life for the clutch and flywheel pair.
Tracking Progress and Real-World Feedback
Engineers and enthusiasts often document the long-term performance of a Twin Plate clutch in community forums and performance shops. Real-world feedback highlights how the system behaves under varying temperatures and driving styles, including street starts, highway bursts, and track sessions. Observing clutch pedal feel, noise, and slip characteristics across a few drive cycles provides valuable data for fine-tuning the setup. If a persistent issue arises, it is wise to recheck the alignment, clutch disc seating, and release bearing operation before proceeding to more invasive adjustments.
Final Checks Before Hit the Road
Before returning to normal driving or a race day routine, perform a comprehensive systems check. Confirm all electrical connections are secure, the transmission fluid level is correct, and the exhaust system is free from rubbing or contact with the underbody components. A test drive with progressive power application helps verify that the clutch engages smoothly at multiple RPM ranges and under varied loads. Document any deviations in pedal feel or power delivery, as these notes guide future maintenance or minor adjustments to the clutch assembly or drivetrain mounts.
