Piston Wrist Pin Buttons, 87mm

OVERVIEW

In the high-stakes world of air-cooled engine building, the smallest components often dictate the longevity of your entire investment. These EMPI 87mm Teflon Piston Wrist Pin Buttons are designed to eliminate one of the most common failure points in a performance Volkswagen engine: the "clip of death." Standard wire clips or circlips can become brittle over time, lose their tension, or be installed incorrectly, leading them to pop out of the wrist pin groove. When a clip fails, the steel wrist pin is free to "walk" out and gouge deep, irreparable furrows into your cylinder walls. By replacing those fragile clips with these high-grade Teflon buttons, you provide a soft, self-lubricating barrier that keeps the wrist pin centered without the risk of metal-on-metal contact or mechanical failure. It''s the ultimate insurance policy for any 1641cc big-bore build where reliability is just as important as horsepower.

Engineered specifically for 87mm piston sets, these buttons are a favorite among professional engine builders and weekend enthusiasts alike. Unlike metal clips that require specialized pliers and a prayer to seat correctly, these Teflon buttons simply slide into the ends of the wrist pins. Because Teflon is softer than the cast iron or steel used in cylinder barrels, these buttons can kiss the cylinder wall without causing any wear or scoring, effectively "floating" the pin in a perfectly centered position. This setup is particularly beneficial for high-RPM applications or off-road engines where vibration and thermal expansion can cause traditional clips to fatigue. When you are building an engine that you expect to last for tens of thousands of miles, upgrading to these EMPI buttons is a common-sense modification that pays for itself the first time you don''t have to tear down a motor due to a failed $0.50 clip.

FITMENT

These 87mm wrist pin buttons are designed for air-cooled Volkswagen Type 1 based engines utilizing 87mm "Slip-In" Big Bore piston and cylinder kits. This typically results in a 1641cc displacement when used with a standard 69mm stroke crankshaft.

• Volkswagen Type 1: Beetle, Bug, and Super Beetle (1966-1977)
• Volkswagen Type 2: Bus, Transporter, Station Wagon (1966-1971)
• Volkswagen Type 3: Fastback, Squareback, Notchback (1966-1973)
• Volkswagen Karmann Ghia: (1966-1974)
• Volkswagen Thing: (1973-1974)
• Custom Applications: Dune Buggies, Sand Rails, and Trikes using VW 1600cc based cases with 87mm pistons.

SPECS

The following technical specifications ensure these buttons meet the rigorous demands of a performance air-cooled environment:

• Piston Diameter Compatibility: 87mm
• Material: High-Temperature Resistant Virgin Teflon (PTFE)
• Quantity: 8 Pieces (Full set for one 4-cylinder engine)
• Manufacturer: EMPI
• Part Number: 4594-11
• Function: Replaces standard metal wrist pin circlips/wire locks
• Lubrication: Self-lubricating material properties
• Installation Type: Slip-fit into wrist pin ends

PRO TIPS

1. Verify Pin Length and Button Depth

Before final assembly, always slide your wrist pin into the piston with a Teflon button on each end. Use a feeler gauge or a visual check to ensure the buttons sit flush or slightly sub-flush with the piston skirt diameter. If the pin/button combo is too long, it can create excessive side-load against the cylinder wall. While Teflon is soft, you don''t want the assembly to be "wedged" in. In rare cases with aftermarket pistons, you may need to lightly sand the flat face of the button to achieve the perfect clearance, though these are precision-molded for standard 87mm sets.

2. Cleanliness is Crucial for Seating

Even though Teflon is self-lubricating, you must ensure the internal bore of the wrist pin is completely free of metal shavings, packing grease, or carbon buildup before inserting the buttons. Any debris trapped behind the button can prevent it from seating fully, which might lead to the button protruding too far and catching on a port or the cylinder edge during assembly. Give the wrist pins a thorough bath in parts cleaner and a blast of compressed air before "buttoning" them up for the final time.

3. Orientation and Ring Gap Considerations

When installing your pistons into the cylinders with Teflon buttons, pay close attention to your ring gap orientation. Ensure that your piston ring gaps are not aligned directly over the wrist pin holes where the buttons reside. While the buttons provide a smooth surface, keeping the combustion pressure and ring tension away from the pin bore area helps maintain a better seal and prevents any potential "snagging" during the high-speed reciprocation of the piston. Always use a high-quality ring compressor to ensure the piston and buttons slide into the bore without force.