Rocker Arm Shim Set, .030 Thick, 8 Pieces

OVERVIEW

Precision is the hallmark of a high-performance air-cooled engine, and the EMPI Rocker Arm Shim Set is an essential component for any builder seeking to achieve perfect valvetrain geometry. When you are assembling a performance engine or even refreshing a stock 1600cc dual-port, the factory wavy washers often fail to provide the rigid side-play control required for high-RPM stability. These .030-inch thick shims are designed to replace those flimsy stock components or to be used in conjunction with bolt-on rocker shafts to eliminate excessive lateral movement. By narrowing the side-play tolerances, you ensure that the rocker arm remains perfectly centered over the valve stem tip, which prevents uneven wear on the valve guides and eliminates the annoying "clatter" often associated with loose air-cooled valvetrains. Whether you are running stock 1.1:1 rockers or high-lift 1.4:1 ratio rockers, these shims provide the repeatable accuracy needed for a professional-grade build.

At Appletree Automotive, we know that the smallest details often make the biggest difference in engine longevity. These EMPI shims are manufactured from high-quality, hardened steel to withstand the constant reciprocating motion and thermal stress found within the cylinder head environment. Using a .030-inch shim allows for significant adjustment when "shimming out" a rocker assembly to achieve the ideal .004 to .006 inches of side play. Without proper shimming, rocker arms can walk across the valve tip, leading to side-loading of the valve stem and premature failure of the valve seals and guides. This set of eight pieces provides enough material to outfit a complete engine, giving you the tools necessary to dial in your rocker geometry for maximum lift, reduced friction, and a much quieter top end. Don''t settle for "close enough" when you can achieve mechanical perfection with these precision-ground spacers.

FITMENT

These rocker arm shims are designed for use with standard and high-performance rocker shafts in the following Volkswagen models:

• Volkswagen Type 1: Beetle and Super Beetle (1954-1979)
• Volkswagen Type 2: Bus, Transporter, and Kombi (1954-1971)
• Volkswagen Type 3: Fastback, Squareback, and Notchback (1961-1973)
• Volkswagen Karmann Ghia: All Years (1955-1974)
• Volkswagen Thing: Type 181 (1973-1974)
• Custom Applications: Dune Buggies, Sand Rails, and Trikes utilizing Type 1 based air-cooled engines (1200cc, 1300cc, 1500cc, and 1600cc based builds).

SPECS

• Brand: EMPI
• Part Number: 4018-11
• Thickness: .030 Inches (0.76mm)
• Inner Diameter (ID): .710 Inches
• Material: Hardened Steel for wear resistance
• Quantity: 8 Pieces per set
• Application: Rocker Arm Side Play Adjustment
• Compatibility: Fits most stock and aftermarket high-performance rocker shafts

PRO TIPS

PRO TIP 1: Measuring Side Play with Precision. When installing these shims, always use a high-quality feeler gauge to measure the gap between the rocker arm and the shaft support or the adjacent shim. For a street-driven air-cooled VW, we recommend a side-play clearance of .004 to .006 inches. If the fitment is too tight, the rocker arm may bind as the engine reaches operating temperature and the metals expand. If it is too loose, you will experience excessive noise and potential valvetrain damage. Always check every single rocker arm individually, as manufacturing tolerances in the heads and shafts can vary slightly from one cylinder to the next.

PRO TIP 2: Centering the Rocker on the Valve Tip. The primary goal of shimming isn''t just to stop the noise; it''s to ensure the rocker arm''s adjuster screw or roller tip is perfectly centered on the valve stem. Before final assembly, install your rocker shaft with the shims and rotate the engine by hand. Observe the "sweep" of the rocker across the valve tip. If the contact point is off-center, you may need to move shims from one side of the rocker arm to the other. Proper centering reduces side-loading on the valve guides, which is the number one cause of "smoking" on deceleration in high-performance VW engines.

PRO TIP 3: Upgrade to Bolt-On Rocker Shafts. While these .030 shims can be used with stock-style shafts that utilize spring clips and wavy washers, they perform best when paired with high-performance bolt-on rocker shafts. Bolt-on shafts eliminate the flex and "snap-ring pop" common in high-lift applications. When using bolt-on shafts, you will completely discard the stock wavy washers and replace them with a combination of these .030 shims and thinner .010 or .015 shims to achieve the perfect stack-up height. This creates a rigid, race-ready valvetrain that can handle high-revving performance without the risk of the rocker assembly shifting out of alignment.