Absolute CNC Products – Copper Cylinder Head Gasket (O.S Engines)

Absolute CNC Products – Copper Cylinder Head Gasket

O.S. 105HZ / 105HZ-R

0.012" (0.3mm) Annealed Copper

The Absolute CNC Products Copper Cylinder Head Gasket is designed specifically for the O.S. 105HZ and 105HZ-R nitro helicopter engines. Precision cut from high-quality annealed copper, this gasket provides excellent sealing performance while offering a simple and effective method for reducing compression ratio when running higher nitro fuel blends.

Commonly used with 23% and 30% nitromethane fuel, the 0.3mm thickness helps improve tuning stability and reduce the likelihood of pre-detonation in high-performance applications.

Unlike stacked OEM shims, this single-piece copper gasket offers a durable, uniform sealing surface with excellent heat transfer characteristics and long service life.

Features

• Precision-cut annealed copper construction
• Helps reduce compression ratio for high nitro fuel applications
• Excellent heat resistance and sealing properties
• Durable single-piece design
• Consistent thickness for reliable engine tuning
• Ideal for aggressive 3D and high-performance nitro flying

Specifications

• Material: Annealed Copper
• Thickness: 0.012" (0.3mm)
• Compatibility: O.S. 105HZ, O.S. 105HZ-R

Tuning Information

The 0.3mm cylinder head gasket is commonly used with:

• 23% nitro fuel
• 30% nitro fuel

Recommended glow plugs:

• O.S. #8
• ENYA #4

If pre-detonation occurs, try:

• O.S. #10
• ENYA #5

This gasket thickness is approximately equivalent to stacking two OEM head shims:

• 0.1mm OEM gasket
• 0.2mm OEM gasket

This combination is frequently recommended to help reduce compression ratio when operating on 30% nitro fuel.

Installation Notes

Ensure all gasket and mating surfaces are clean before installation. Because annealed copper is soft and highly conformable, handle the gasket carefully to avoid bending or deformation.

Always avoid running excessively lean fuel mixtures, as lean conditions can cause severe engine damage. Follow the manufacturer’s baseline needle settings before fine tuning.

Proudly offered by Absolute CNC Products for pilots who demand reliability, precision, and performance from their nitro engine setups.