Copper Cylinder Head Gaskets, Fits 94mm, .050 In Thick

OVERVIEW

Precision is the hallmark of a high-performance air-cooled engine, and when you are building a powerhouse using 94mm cylinders, every thousandth of an inch matters. These EMPI Copper Cylinder Head Gaskets are engineered to be the ultimate solution for engine builders looking to fine-tune their deck height and compression ratio with absolute accuracy. In the world of high-output Volkswagens, whether you are running a 1914cc, a 2276cc, or a massive 2332cc monster, achieving the perfect "squish" area is critical for preventing detonation and maximizing combustion efficiency. These .050-inch thick copper shims provide a reliable, malleable barrier between the cylinder top and the head, allowing for a superior seal that standard metal-to-metal contact simply cannot match. When your heads have been flycut for higher compression or your stroker crank has pushed the pistons too far out of the hole, these gaskets are the professional builder''s choice to bring everything back into spec.

Beyond simple spacing, the use of high-grade copper offers significant thermal advantages that are vital for the longevity of an air-cooled flat-four. Copper possesses exceptional thermal conductivity, helping to bridge the heat transfer between the cylinder barrels and the cylinder heads, which reduces localized hot spots and prevents head warping under extreme load. Unlike composite gaskets that can blow out or steel shims that are too rigid to conform to minor surface imperfections, these copper gaskets "crush" slightly upon torquing, creating a gas-tight seal that holds up even in high-compression or turbocharged applications. At Appletree Automotive, we know that reliability is just as important as horsepower, and adding these gaskets to your build is a cost-effective insurance policy against head leaks and costly engine teardowns. Whether you are building a weekend cruiser, a heavy-duty Transporter, or a dedicated sand rail, these 94mm gaskets deliver the consistency you need for a rock-solid bottom end and a crisp-running top end.

FITMENT

These 94mm copper cylinder head gaskets are designed for high-performance Volkswagen Type 1, 2, and 3 engines utilizing oversized 94mm piston and cylinder kits. They are compatible with the following applications:

• Volkswagen Beetle: Custom high-performance builds (1914cc, 2110cc, 2276cc, 2332cc).
• Volkswagen Karmann Ghia: Performance engine upgrades using 94mm bores.
• Volkswagen Bus / Type 2: 1600cc based engines modified for larger displacement.
• Volkswagen Type 3 (Squareback, Fastback, Notchback): Custom performance builds.
• Volkswagen Thing (Type 181): Off-road and performance modified engines.
• Dune Buggies & Sand Rails: Any air-cooled VW-based rail running 94mm cylinders.
• Custom Trikes: VW-powered trike builds requiring deck height adjustment.

SPECS

Engineered for exact tolerances, these gaskets meet the following technical specifications:

• Bore Size: 94mm (Designed for 94mm cylinders).
• Thickness: .050 Inches (1.27mm).
• Material: High-Grade Annealed Copper for superior sealing and heat dissipation.
• Quantity: Sold as a complete set of 4 pieces.
• Application: Head-to-Cylinder sealing and deck height shim.
• Manufacturer: EMPI.
• Part Number: 4579-31.
• Compatibility: Fits most aftermarket 94mm cylinder barrels (Mahle, AA Performance, etc.).

PRO TIPS

1. The Art of Annealing for a Perfect Seal

While these gaskets are ready to use out of the package, many master builders prefer to "anneal" copper gaskets before installation to ensure they are as soft and malleable as possible. To do this, carefully heat the copper gaskets with a propane torch until they reach a dull cherry red color, then immediately quench them in a bucket of clean water. This process resets the molecular structure of the copper, making it extremely soft so that it perfectly conforms to any microscopic irregularities in the cylinder head or the top of the barrel. This is especially helpful if you are reusing gaskets or if your heads have seen many heat cycles. Always ensure the gaskets are perfectly flat and free of debris before placing them on the engine.

2. Calculating Your Compression Ratio Correctly

Don''t guess when it comes to your deck height! When using a .050-inch shim, you are significantly increasing the volume of the combustion chamber. You must measure your "piston-to-deck" height without the gasket first (the distance the piston sits below or above the cylinder rim at Top Dead Center). Add the .050-inch gasket thickness to that measurement to find your total deck height. Ideally, for a high-performance street engine, you want a total deck height between .040 and .060 inches. If your deck height is too tight (less than .035 inches), you risk the piston hitting the head at high RPM due to rod stretch. If it is too loose, you lose the "quish" effect, which can lead to a sluggish engine that is prone to overheating.

3. Use Sealing Compounds Sparingly

In many cases, copper gaskets can be installed "dry" because the soft metal acts as its own sealant when torqued down. However, for extra insurance against oil weeping or combustion leaks, a very thin coating of a high-temperature sealant like Permatex Copper Spray-A-Gasket or Gasgacinch can be applied. If you choose to use a spray, apply a light, even coat to both sides of the gasket and let it become "tacky" (usually 30-60 seconds) before placing it on the cylinder. Avoid using thick RTV silicone or heavy pastes, as these can squeeze out into the combustion chamber or interfere with the precision thickness of the shim, defeating the purpose of using a .050-inch spacer in the first place.