Keep Your RB26DETT Valvetrain in Control at 8,500 RPM and Beyond
High-RPM reliability for the RB26DETT begins with keeping the valvetrain under control. The HKS Upgraded Valve Spring Kit Step 2 (22001-AN001) is engineered specifically for the Nissan Skyline GT-R’s twin-turbocharged six-cylinder, designed to withstand the increased valvetrain stress that comes with upgraded camshafts, higher boost, and extended redlines. When the stock valve springs become a weak link at 8,000 rpm and beyond, this kit is the direct solution.
Built for the RB26DETT at High RPM
The HKS 22001-AN001 valve spring kit is the required companion for HKS Step 2 camshaft applications on the RB26DETT. Stock valve springs on the BNR32, BCNR33, and BNR34 are rated for approximately 7,600 rpm. With HKS Step 2 camshafts installed, the allowable rev ceiling rises to 8,000 rpm on stock springs, but upgrading to 22001-AN001 pushes that limit to 8,500 rpm and dramatically reduces the risk of valve float and coil-bind at sustained high-RPM operation. Step 2 was designed to support power output targets of 600ps or higher. Each spring undergoes stringent shot-peening and heat treatment to deliver consistent spring rates over the full service life of the engine.
Key Features
- Purpose-built for RB26DETT with HKS Step 2 camshafts (and recommended for Step Pro applications)
- Raises allowable RPM from 8,000 rpm (stock springs) to 8,500 rpm when combined with Step 2 camshafts
- Reduces risk of valve float and coil-bind under high-lift, high-RPM operation
- Shot-peening and heat treatment process ensures consistent spring rate over time
- Compatible with HKS V-CAM STEP 2 system (22007-AN018) for maximum variable valve timing range
- Designed for use with HKS Step 2 camshafts; supports 264 to 272 degree duration profiles
- Fits BNR32, BCNR33, and BNR34 cylinder heads (Nissan Skyline GT-R R32, R33, R34)
- MPN: 22001-AN001 | HKS Part: 22001-AN001 | Reference: HKS 22001-AN001
Step 2 Camshaft Compatibility Reference
| Camshaft Type | Valve Spring Required | Max RPM (Stock Springs) | Max RPM (22001-AN001) |
|---|---|---|---|
| HKS Step 1 | Stock (optional upgrade) | 8,000 rpm | 8,000 rpm |
| HKS Step 2 (272 deg) | 22001-AN001 recommended | 8,000 rpm | 8,500 rpm |
| HKS Step Pro | 22001-AN001 required | Not recommended | 8,800 rpm |
What’s Included
- 1x Set of HKS Upgraded Valve Springs for RB26DETT Step 2 (22001-AN001)
- Full engine valve count per the RB26DETT cylinder head (springs for all 12 valves)
Note: This kit includes valve springs only. Titanium retainers, stem seals, and camshafts are sold separately. HKS recommends using titanium retainers when targeting maximum RPM with these springs.
Technical Specifications
| Specification | Value |
|---|---|
| Part Number (MPN) | 22001-AN001 |
| Application | Nissan RB26DETT (BNR32, BCNR33, BNR34) |
| Kit Level | Step 2 |
| Recommended With | HKS Step 2 or Step Pro camshafts |
| Max Allowable RPM (with kit) | 8,500 rpm (Step 2 cam) / 8,800 rpm (Step Pro cam) |
| Compatible Cam Duration | 264 to 272 degrees and above |
| Treatment | Shot-peened and heat-treated |
| Fitment | Nissan Skyline GT-R R32 (1989-1994), R33 (1995-1998), R34 (1999-2002) |
| Engine | RB26DETT (2,568cc twin-turbocharged inline-6) |
| UPC | N/A |
| Brand | HKS |
Installation Instructions
- Remove the cylinder head from the RB26DETT block following the factory service manual procedure. Drain coolant and oil as required.
- Disassemble the valvetrain: remove camshafts, bucket lifters, and valve caps. Label all components for reinstallation in original positions if reusing stock parts.
- Using a valve spring compressor, depress each stock valve spring and remove the collets, retainer, and spring. Repeat for all 12 valves.
- Inspect valve stems and stem seals. Replace stem seals as recommended. HKS reinforced stem seals (22999-AN004) are available separately and recommended for high-RPM applications.
- Install the HKS 22001-AN001 upgraded springs, ensuring the spring seat is clean. Install retainers and collets. If using titanium retainers, confirm they are compatible with the collet groove dimensions.
- Reassemble the cylinder head, installing camshafts according to the HKS camshaft installation guide if upgraded cams are also being installed.
- Reinstall the cylinder head with a new head gasket (HKS recommends a stopper-type or grommet-type head gasket for modified engines). Torque head bolts to factory specification or use HKS reinforced head bolts if available.
- Adjust valve timing and clearances per camshaft specifications. Set cam timing using adjustable cam pulleys if installed.
- Perform a controlled break-in with oil temperature monitoring before sustained high-RPM operation.
Frequently Asked Questions
Does this kit fit the R32 GT-R with the RB26DETT?
Yes. The HKS 22001-AN001 is explicitly listed for BNR32 (R32 GT-R, 1989 to 1994), BCNR33 (R33 GT-R, 1995 to 1998), and BNR34 (R34 GT-R, 1999 to 2002) with the RB26DETT engine.
Do I need these springs if I am only installing Step 1 camshafts?
Step 1 camshafts can operate with stock valve springs up to approximately 8,000 rpm. HKS recommends the 22001-AN001 for Step 2 applications and requires them for Step Pro applications. For Step 1 builds targeting maximum reliability at 8,000 rpm, upgrading to 22001-AN001 is still a worthwhile precaution.
Are retainers included with this kit?
No. This kit contains valve springs only. Retainers, specifically the titanium retainers HKS recommends for high-RPM Step 2 and Step Pro builds, are sold separately.
What camshaft duration profile is compatible with 22001-AN001?
The HKS 22001-AN001 is designed for use with HKS Step 2 camshafts (272 degree duration, 10.2mm lift) and Step Pro camshafts on the RB26DETT. It is referenced in the HKS V-CAM Step 2 system documentation as the correct companion spring for builds targeting 8,500 to 8,800 rpm.
Will these springs work with the HKS V-CAM system?
Yes. HKS specifically references 22001-AN001 as the recommended valve spring for the RB26 V-CAM Step 2 system (22007-AN018) when targeting the 8,500 rpm allowable speed limit. They are also listed in HKS’s complete 2.8L engine build documentation.
How many springs are included in the kit?
The kit includes a full set of valve springs for the RB26DETT cylinder head, covering all 12 intake and exhaust valves (one spring per valve in the RB26DETT design).
Is professional installation required?
Yes. Valve spring replacement requires full cylinder head disassembly, a valve spring compressor tool, and familiarity with torque specifications and valve timing procedures. This work should be performed by an experienced engine builder or performance shop.
Can these springs be used with stock RB26DETT pistons and rods?
The valve springs themselves are compatible with stock pistons; however, HKS notes that Step 2 camshafts (which these springs accompany) require HKS forged pistons to ensure adequate valve-to-piston clearance on the RB26DETT. Valve springs alone do not affect piston clearance.
What is the recommended oil for high-RPM RB26DETT builds using these springs?
HKS recommends HKS Super Turbo Racing 15W50 or HKS Racing Pro 10W50 for complete RB26 Step 2 engine assemblies.
WARNING: This product can expose you to chemicals including nickel compounds, which are known to the State of California to cause cancer, and carbon monoxide, which is known to cause birth defects or other reproductive harm. For more information, visit www.p65warnings.ca.gov.
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