Piston Wrist Pin Buttons, 94Mmm

OVERVIEW

When you are building a high-performance air-cooled engine, the smallest components often provide the most critical insurance against catastrophic failure. These 94mm Teflon Piston Wrist Pin Buttons are designed to replace the traditional wire circlips or "spiral locks" that hold your wrist pins in place. In a high-revving Volkswagen engine, stock wrist pin clips are a known weak point; if a clip becomes fatigued or is improperly seated, it can pop out of its groove and gouge a deep, irreparable trench into your cylinder wall. By switching to these EMPI Teflon buttons, you eliminate that risk entirely. These buttons are engineered to ride directly against the cylinder wall, providing a "full-floating" wrist pin setup that is both self-lubricating and incredibly durable. Because Teflon is significantly softer than the cast iron or steel used in cylinder barrels, these buttons will not score or damage your bores, even under the intense heat and pressure of a 2276cc or 2332cc stroker motor.

Installation is significantly simpler and safer than struggling with high-tension internal circlips that often go flying across the garage during assembly. These buttons simply slide into the ends of the wrist pin, filling the gap between the pin and the cylinder wall. This design ensures that the wrist pin stays centered within the connecting rod and piston boss while allowing for the natural thermal expansion that occurs during hard driving. Whether you are building a weekend cruiser, a rugged off-road rail, or a dedicated drag strip Beetle, these buttons offer peace of mind that a 50-cent clip won''t ruin a multi-thousand-dollar long block. This set includes eight pieces, providing a complete solution for a four-cylinder air-cooled engine using 94mm pistons. Don''t leave your engine''s longevity to chanceupgrade to the industry standard for performance VW piston retention.

FITMENT

These 94mm Teflon wrist pin buttons are designed for use in Volkswagen Type 1, 2, and 3 engines equipped with 94mm bore pistons. This typically includes high-displacement performance builds. Common fitment includes:

• Volkswagen Beetle: 1950 through 1979 (Standard and Super Beetle).
• Volkswagen Karmann Ghia: 1956 through 1974.
• Volkswagen Bus / Type 2: 1950 through 1971 (with Type 1 based upright engines).
• Volkswagen Type 3 (Squareback, Fastback, Notchback): 1961 through 1973.
• Volkswagen Thing (Type 181): 1973 through 1974.
• Custom Applications: Sand Rails, Dune Buggies, and Trikes utilizing 94mm Piston/Cylinder kits (1914cc, 2110cc, 2276cc, 2332cc, etc.).

SPECS

Detailed technical specifications for the EMPI 4594-14 Wrist Pin Buttons:

• Piston Diameter Compatibility: 94mm.
• Material: High-density, heat-resistant Virgin Teflon.
• Quantity: 8 Pieces (Complete set for 4 pistons).
• Retention Style: Full-floating, button-style (eliminates circlips).
• Part Number: 4594-14 (EMPI).
• Color: White / Natural Teflon finish.
• Weight: Ultra-lightweight to reduce reciprocating mass.
• Compatibility: Works with most Mahle, AA Performance, and Wiseco 94mm piston sets.

PRO TIPS

1. Check Your End Play Clearance

Before final assembly, always mock up one piston and wrist pin assembly inside the cylinder. Slide the wrist pin and both Teflon buttons into the piston, then slide the piston into the cylinder barrel. There should be a very slight amount of side-to-side movement (clearance) between the buttons and the cylinder walltypically around .010" to .020". If the buttons are too tight against the wall, they can expand when hot and cause excessive friction. If they are too long, you can carefully sand the flat face of the button with fine-grit sandpaper on a flat surface to achieve the perfect fit. Never force a piston into a cylinder if the buttons feel like they are binding.

2. Lubricate for Initial Startup

While Teflon is naturally self-lubricating, you should always apply a small dab of high-quality assembly lube or clean engine oil to the outer face of the button and the wrist pin itself during installation. This ensures that during the critical first few seconds of the engine''s life, there is zero dry friction between the button and the cylinder wall. Once the engine is running, the oil mist inside the crankcase will provide more than enough lubrication to keep the buttons sliding smoothly against the cross-hatched cylinder walls.

3. Clean the Wrist Pin Bore Thoroughly

Because these buttons sit inside the hollow ends of your wrist pins, it is vital that the interior of the wrist pin is completely free of debris, machining burrs, or packing grease. Use a lint-free cloth and brake cleaner to scrub the inside of the pins before inserting the buttons. Any grit trapped between the button and the pin can prevent the button from seating fully, which may lead to incorrect clearance measurements. Double-check that the buttons are seated flush against the ends of the pin so they don''t "walk" or shift during the engine''s operation.