Comp Cams-4757 Valve Spring Shim Kit - 1.500" OD Assortment Instruction Manual

1. Introduction

This instruction manual provides essential information for the proper use and installation of the Comp Cams-4757 Valve Spring Shim Kit. This kit is designed to assist in achieving precise valve spring installed heights in automotive engine applications. Adhering to these instructions will help ensure optimal performance and longevity of your valve train components.

2. Product Overview

The Comp Cams-4757 Valve Spring Shim Kit contains an assortment of shims with specific dimensions and thicknesses. These shims are critical for equalizing the installed height of valve springs, which can vary due to manufacturing tolerances in cylinder heads, valve lengths, valve springs, retainers, and locks. Correct installed height directly impacts spring seat and open pressures, which are vital for engine operation.

The shims are manufactured from high-quality shim stock steel and are heat-treated to withstand the demands of radical camshaft profiles and high-performance engine environments. This ensures consistent and reliable performance.

This image displays three rows of black, circular valve spring shims. Each row contains multiple shims, illustrating the assortment of thicknesses included in the kit. The shims have a central opening and are designed to adjust valve spring installed height.

Kit Contents:

• 16 x 0.015" Thick Shims
• 16 x 0.030" Thick Shims
• 16 x 0.060" Thick Shims

All shims in this kit feature a 1.500" Outside Diameter (OD) and a 0.645" Inside Diameter (ID).

3. Setup and Installation

Accurate measurement of valve spring installed height is crucial for proper engine assembly. This process typically involves specialized tools and careful attention to detail.

Installation Steps:

1. Measure Initial Installed Height: Before installing the valve springs, measure the installed height of each valve spring without shims. This measurement is taken from the spring seat to the underside of the retainer.
2. Determine Required Shim Thickness: Compare the measured installed height to the manufacturer's recommended installed height for your specific valve springs. The difference will indicate the total shim thickness required to achieve the target height.
3. Select Shims: Choose the appropriate combination of 0.015", 0.030", and 0.060" shims from the kit to reach the desired thickness. Multiple shims can be stacked if necessary, ensuring they are clean and free of debris.
4. Place Shims: Position the selected shims directly on the spring seat in the cylinder head.
5. Install Valve Spring: Carefully install the valve spring, retainer, and locks over the shims.
6. Verify Installed Height: Re-measure the installed height to confirm that the correct height has been achieved. Adjust shim thickness as needed.

Note: Production tolerances can cause variations in installed height from valve to valve. It is essential to measure and shim each valve individually to ensure consistent spring pressures across all cylinders.

4. Operating Considerations

Once installed, the valve spring shims function passively to maintain the correct valve spring installed height. No active 'operation' is required from the shims themselves. Their primary role is to ensure the valve springs operate within their intended specifications, providing the correct seat and open pressures for optimal valve train control.

The shims are designed to withstand the high forces and temperatures present in an engine's valve train. Their heat-treated construction ensures durability and resistance to deformation under extreme conditions.

5. Maintenance

Valve spring shims are generally maintenance-free components once correctly installed. However, during any subsequent valve train inspection or service, it is advisable to:

• Inspect for Wear: Check shims for any signs of wear, pitting, or deformation. While highly durable, extreme conditions or improper installation can lead to issues.
• Cleanliness: Ensure shims and spring seats are clean and free of debris during reassembly.
• Re-measure: If valve springs or other valve train components are replaced, always re-measure and adjust installed heights as necessary.

Store unused shims in a clean, dry environment to prevent corrosion or damage.

6. Troubleshooting

Improper valve spring installed height, often due to incorrect shimming, can lead to several engine performance issues:

• Incorrect Spring Pressure: If installed height is too high (insufficient shims), spring pressure will be too low, potentially causing valve float at high RPMs. If installed height is too low (excessive shims), spring pressure will be too high, leading to premature wear of valve train components (camshaft, lifters, rocker arms) and increased parasitic losses.
• Valve Train Noise: Excessive lash or improper spring tension can result in audible clicking or clattering from the valve train.
• Reduced Engine Performance: Valve float or excessive friction can lead to a loss of power and efficiency.

If any of these symptoms are observed, it is recommended to re-check valve spring installed heights and adjust shimming as required. Always consult your engine builder or a qualified mechanic if you are unsure about the correct procedure or diagnosis.

7. Specifications

8. Warranty and Support

Specific warranty information for the Comp Cams-4757 Valve Spring Shim Kit is not provided in this document. For details regarding product warranty, please refer to the official Comp Cams website or contact their customer support directly.

For technical assistance or further inquiries, please visit the Comp Cams official website or contact their customer service department.