GTR Engine Rebuild: A Detailed Guide

The world of high-performance automotive engineering often presents challenges that can seem daunting to the uninitiated. Rebuilding a legendary engine like the Nissan Skyline's RB26DETT is a prime example. While information can feel scattered across forums and old threads, this guide aims to consolidate practical advice and essential steps for those undertaking such a significant project. We'll delve into the intricacies of engine reinstallation, clutch considerations, and even a detailed look at rebuilding a common starter motor fault, offering a practical roadmap for enthusiasts.

Engine Reinstallation: A Delicate Dance

Once your RB26DETT has undergone its rebuild, the process of reinstalling it is a critical phase that demands patience and precision. Many components need to be connected before the engine is ready to be reunited with the chassis. The foresight to take pictures during disassembly proves invaluable here, serving as a visual reference to ensure everything is correctly reconnected. Cleaning components beforehand significantly streamlines this reassembly process, reducing the time needed to refit everything.

Clutch Considerations: From Nismo to Exedy

A common upgrade during an engine rebuild involves the clutch. The original setup might be replaced with a more robust unit to handle increased power. In this instance, a noisy Nismo paddle clutch was swapped for a single-plate Exedy uprated version. The crucial step in clutch installation is alignment. A genuine input shaft from an old Skyline gearbox is the ideal tool for accurately lining up the clutch. These are not always readily available, but borrowing one from a specialist like Abbey Motorsport can make a significant difference.

Rigging for Success: Heavy Lifting and Safety

The RB26DETT, when fully dressed with turbos, inlet manifold, and sump, is a considerably heavy unit, weighing in at approximately 250kg. Correct rigging is paramount to prevent accidents. The initial rigging failed, causing the rebuilt engine to drop about a metre onto paving slabs and the front of the car. Miraculously, the engine block sustained no major damage, landing on a corner and only causing superficial damage to the paving and front bumper. This incident highlights the importance of using appropriate, heavy-duty rigging. Even a robust 250kg engine stand can be compromised by the sheer weight of a fully assembled RB26DETT, as evidenced by the bent stand in this case. Always double-check your lifting equipment and ensure it's rated for the task.

When reintroducing the engine, lifting the front of the engine above the flywheel end can significantly ease the process compared to its removal. The key is to align the gearbox and engine splines at the correct angle. Initially, the resistance felt during spline engagement might seem excessive, but this is often characteristic of these transmissions. Once the splines engage, you know the engine is correctly seated. The next step is to bolt the engine securely to the gearbox.

Finishing Touches: Refitting Ancillaries

With the engine and gearbox married, the focus shifts to refitting the remaining components. This includes driveshafts, pumps, wiring looms, and various hoses. While these tasks might seem straightforward, they require careful attention to detail to ensure all connections are secure and properly routed.

Starter Motor Recon: Restoring Cranking Power

A common issue plaguing RB engines is starter motor failure. Often, these units don't require a complete replacement but rather a thorough clean and service. For those with a modicum of mechanical aptitude, rebuilding a starter motor can be a cost-effective DIY job, boosting confidence in the process. The starter motor can typically be accessed and removed from underneath the vehicle, even the top bolt can be reached with a short spanner.

Starter Motor Diagnosis and Disassembly

Symptoms of a failing starter motor often manifest as a simple 'click' when the ignition is turned, but no engine cranking. This is usually indicative of dirt and debris interfering with the internal components. The process begins with removing the two 8mm bolts securing the starter. The bottom casing can then be carefully pulled away. The rotor can be gently removed, and the same applies to the other casings. A crucial element to note is the ball bearing that sits atop the shaft within the housing.

Reassembly and Testing

The solenoid screws can be stubborn; if they round off, removing the heads and using pliers to extract the studs, followed by replacement, is a viable solution. Once the solenoid is off, the top part of the starter motor can be separated. WD40 is effective for cleaning moving parts, while isopropyl alcohol is best suited for electrical components. The bottom part of the starter requires careful handling to retract the springs behind the carbon brushes. Using electrical screwdrivers or welding wire can help hold these springs back while the rotor is carefully inserted. The top part is then reassembled, ensuring the ball bearing is correctly seated on the shaft before putting it all back together.

Testing the rebuilt starter motor requires a direct connection to a battery; a charger typically lacks the necessary amperage. When connected correctly, the solenoid should engage, pushing the cog forward, and the main live connection should cause the cog to spin. This simple service has been known to restore intermittent starter motor function, bringing them back to a 'good as new' condition for thousands more miles.

Common Starter Motor Issues and Troubleshooting

It's worth noting that starter motor failures, solenoid issues, and associated relay or fuse problems are relatively common on RB engines. Understanding the basic components and how to service them can save considerable expense. The table below outlines some common terms associated with starter motor problems:

Frequently Asked Questions

Q1: How much does a GTR engine rebuild typically cost?
Costs vary significantly depending on the extent of the rebuild, parts used, and labour rates. A basic refresh could be a few thousand pounds, while a full performance rebuild with upgraded components can easily exceed £10,000.

Q2: Can I rebuild an RB26DETT myself?
Yes, with the right tools, knowledge, and a significant amount of patience, a DIY rebuild is possible. However, precision is key, and mistakes can be costly. It's advisable to have a solid understanding of engine mechanics or seek guidance from experienced professionals.

Q3: What are the common failure points of an RB26DETT?
Beyond starter motor issues, common concerns include the oil pump (especially on early models), head gasket failures due to detonation, and turbocharger wear. Regular maintenance and careful driving are crucial.

Q4: What's the best way to align a clutch during installation?
Using a dedicated clutch alignment tool or an input shaft from a compatible gearbox is the most effective method to ensure the clutch disc is perfectly centred before mating the gearbox to the engine.

Q5: Is it safe to reuse old engine bolts?
For critical components like head bolts and main bearing cap bolts, it is highly recommended to use new, quality replacements. Reusing old bolts, especially torque-to-yield types, can compromise structural integrity and lead to catastrophic engine failure.

Embarking on a GTR engine rebuild is a challenging yet rewarding endeavour. By approaching the task with meticulous planning, the right tools, and a commitment to quality, you can bring your legendary RB26DETT back to its former glory. Remember, attention to detail is your greatest ally.