Copper Cylinder Head Gaskets, Fits 90.5 & 92mm, .060 Thick

OVERVIEW

When you''re building a high-performance air-cooled engine, precision is the difference between a powerhouse and a paperweight. These EMPI copper cylinder head gaskets (often referred to as shims) are engineered for the serious engine builder who understands that deck height is everything. In the world of Volkswagen Type 1 engines, achieving the perfect compression ratio often requires more than just standard machining. Whether you are running a 90.5mm or a 92mm bore, these .060-inch thick gaskets allow you to fine-tune the distance between the piston and the cylinder head. This adjustment is critical for preventing piston-to-head contact at high RPMs and for optimizing the quench area of your combustion chamber, ensuring a more efficient burn and reducing the risk of engine-damaging detonation. By utilizing these high-quality copper shims, you gain the ability to dial in your engine''s specifications without the need for costly and permanent machining of the cylinder tops or head faces.

Copper is the gold standard material for these shims because of its incredible thermal conductivity and its unique ability to "give" just enough under torque to form a gas-tight seal. Unlike standard gaskets that might fail under the extreme heat and pressure of a turbocharged or high-compression street engine, these copper gaskets dissipate heat away from the combustion chamber and into the cylinder fins more effectively. This set of four gaskets is designed specifically for the common "thick wall" 90.5mm and 92mm cylinder sets, which share the same outer diameter at the head seating surface. If you have ever heard the dreaded "chirping" sound of a leaking cylinder head under load, you know how vital a perfect seal is. Upgrading to these EMPI copper gaskets provides that extra layer of insurance, ensuring that your Volkswagen remains reliable whether you are blasting through the dunes in a rail or cruising the strip in a lowered Cal-look Beetle.

FITMENT

• Volkswagen Type 1: Beetle and Super Beetle (Equipped with 90.5mm or 92mm cylinders)
• Volkswagen Type 2: Bus, Transporter, and Kombi (Equipped with 90.5mm or 92mm cylinders)
• Volkswagen Type 3: Fastback, Squareback, and Notchback (Equipped with 90.5mm or 92mm cylinders)
• Volkswagen Karmann Ghia: All years (Equipped with 90.5mm or 92mm cylinders)
• Volkswagen Thing (Type 181): All years (Equipped with 90.5mm or 92mm cylinders)
• Custom Applications: Dune Buggies, Sand Rails, and Trikes utilizing VW air-cooled cases and heads.

SPECS

• Bore Size Compatibility: Fits both 90.5mm and 92mm "Thick Wall" cylinders.
• Thickness: .060 Inches (1.52mm).
• Material: High-Quality Annealed Copper.
• Quantity: Set of 4 (Complete for one engine).
• Outside Diameter: Precision cut to match standard 90.5/92mm head steps.
• Part Number: 4579-22.
• Manufacturer: EMPI.

PRO TIPS

1. The Secret of Re-Annealing

While these gaskets come ready to install, many master engine builders recommend "re-annealing" copper gaskets to ensure they are as soft as possible before installation. To do this, carefully heat the gaskets with a propane torch until they reach a dull cherry red color, then immediately quench them in clean water. This process "softens" the molecular structure of the copper, allowing it to crush and conform to any minor imperfections on the cylinder or head surface. This extra step is the pro''s secret to a lifetime seal that won''t leak even under high boost or high compression scenarios.

2. Calculating Your Total Deck Height

Never guess when it comes to deck height. To find your final deck height, measure the distance from the top of the piston at Top Dead Center (TDC) to the top of the cylinder barrel using a dial indicator and a deck height bridge. Once you have that measurement, add the thickness of these .060 gaskets to that number. For a street-driven VW engine, most builders aim for a total deck height between .040 and .060. If your pistons are currently "down in the hole" by .010, adding these gaskets will put you at .070, which is safe but might lower your compression more than desired. Always do the math before final assembly!

3. Use Copper Spray for Added Insurance

To ensure a completely leak-proof seal, we highly recommend applying a light, even coat of a copper-based gasket sealant (such as Permatex Copper Spray-A-Gasket) to both sides of the shim before installation. This spray contains metallic copper to help dissipate heat and fills in microscopic surface scratches that could otherwise lead to a compression leak. When torquing your heads, follow the factory VW "spiral" pattern in three stages to ensure the copper shims are compressed evenly across the entire surface. This prevents the heads from warping and ensures that the pressure is distributed equally across all four cylinders.