Cylinder Shim Set, Fits 85.5, 87 & 88mm, .090 Thick, 4 Pc

OVERVIEW

Achieving the perfect deck height is the hallmark of a master engine builder, and these EMPI .090-inch cylinder shims are the precision tools you need to get the job done right. In the world of air-cooled Volkswagens, deck heightthe distance between the top of the piston at Top Dead Center (TDC) and the top of the cylinder barrelis critical for determining your engine''s compression ratio and the efficiency of the combustion process. If your deck height is too tight, you risk catastrophic piston-to-head contact at high RPMs; if it is too loose, you lose the vital ''''quench'''' effect that prevents detonation and ensures a clean, efficient burn. These shims provide a reliable, professional-grade way to space your cylinders out from the engine case, allowing you to dial in your exact specifications without the need for expensive and irreversible machining of the cylinder heads or piston crowns.

Designed specifically for the most popular performance and stock bore sizes, including 85.5mm, 87mm, and 88mm, this four-piece shim set is an essential component for any serious Type 1, Type 2, or Type 3 engine build. Whether you are assembling a mild 1600cc daily driver, a peppy 1641cc, or a high-revving 1679cc machine-in motor, these .090-thick shims offer a substantial adjustment for builders dealing with stroker crankshafts or variations in engine case deck heights. By placing these high-quality steel shims between the cylinder base and the engine case, you can compensate for manufacturing tolerances and ensure that all four cylinders are perfectly matched in volume and height. This level of consistency is the key to a balanced engine that runs cooler, lasts longer, and delivers the smooth power that Appletree Auto customers expect from their classic VW projects.

FITMENT

This cylinder shim set is designed for VW Type 1 based engines with 85.5mm, 87mm, or 88mm cylinder bores. Fitment includes, but is not limited to, the following models:

• Volkswagen Beetle: 1966-1977 (1300cc-1600cc based engines)
• Volkswagen Karmann Ghia: 1966-1974
• Volkswagen Bus / Transporter: 1963-1971 (Type 1 upright engines)
• Volkswagen Type 3 (Squareback, Fastback, Notchback): 1966-1973
• Volkswagen Thing: 1973-1974
• Custom Applications: Dune Buggies, Sand Rails, and Trikes using VW Type 1 engine cases.
• Bore Size Compatibility: 85.5mm (Stock 1600cc), 87mm (1641cc Slip-in), and 88mm (1679cc Slip-in or Machine-in).

SPECS

• Brand: EMPI
• Part Number: 4557-90
• Material: High-Grade Steel for maximum heat resistance and durability.
• Thickness: .090 inches (approx. 2.28mm).
• Inside Diameter: Sized for 85.5mm, 87mm, and 88mm cylinder barrels.
• Quantity: Set of 4 (Complete set for one engine).
• Function: Adjusts deck height and compression ratio.
• Installation Location: Between the cylinder base and the engine case.

PRO TIPS

1. Precision Measurement is Key

Before installing your shims, you must measure your current deck height using a deck height micrometer or a high-quality depth gauge and a bridge tool. Don''t guess on your measurements. To find your deck height, seat the cylinder firmly against the case (without the shim or seal) and rotate the engine to Top Dead Center (TDC). Measure the distance from the top of the piston to the top edge of the cylinder. Add the thickness of these .090 shims to your measurement to determine your final deck height. A common performance target for a street-driven air-cooled VW is between .040'''' and .060''''.

2. Proper Sealing Technique

When installing cylinder shims, it is vital to ensure a leak-free seal between the engine case and the cylinder barrel. We recommend applying a very thin, even coat of a high-quality, non-hardening sealant, such as Permatex Aviation Form-A-Gasket or Curil T2, to both sides of the shim. Avoid using thick silicone-based RTV, as it can squeeze out and obstruct oil passages or create an uneven mating surface. Clean both the engine case surface and the cylinder base thoroughly with a degreaser before application to ensure the best possible bond.

3. Account for Compression Ratio Changes

Adding a .090-inch shim will significantly increase the volume of your combustion chamber, which in turn lowers