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Start ShoppingCometic C9531 Panhead/Shovelhead/Evo Big Twin Engine Seal - High-Performance Gasket for Harley-Davidson
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Description
Ensure optimal engine performance with Cometic's C9531 seal, engineered for Harley-Davidson Panhead, Shovelhead, and Evolution Big Twin engines. This high-quality composite seal delivers long-lasting durability and reliable sealing to prevent leaks and maintain peak engine efficiency.
Key Features
- Composite Material Construction: Advanced elastomer and fiber blend provides superior resistance to heat, oil, and aging for extended service life.
- Universal Compatibility: Precision-engineered for Harley-Davidson Big Twin engines (Panhead, Shovelhead, Evolution) to ensure perfect fit and function.
- Single-Piece Design: Simplifies installation while maintaining structural integrity to prevent oil leaks and engine damage.
Why Choose This Product
Upgrade your engine's reliability with a Cometic seal that combines OEM-level precision with enhanced durability. This single-piece solution saves time during maintenance while delivering consistent performance under demanding riding conditions. Trusted by mechanics and riders alike for its leak-proof sealing and long-term cost-effectiveness.
SKU:
GM51C0DEEB
MPN:
C9531
UPC:
191070060558
Category:
Gaskets/Seals
Brand:
Cometic
Stock:
Only 5 left!
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Ensure optimal engine performance with Cometic's C9531 seal, engineered for Harley-Davidson Panhead, Shovelhead, and Evolution Big Twin engines. This high-quality composite seal delivers long-lasting durability and reliable sealing to prevent leaks and maintain peak engine efficiency.
Key Features
- Composite Material Construction: Advanced elastomer and fiber blend provides superior resistance to heat, oil, and aging for extended service life.
- Universal Compatibility: Precision-engineered for Harley-Davidson Big Twin engines (Panhead, Shovelhead, Evolution) to ensure perfect fit and function.
- Single-Piece Design: Simplifies installation while maintaining structural integrity to prevent oil leaks and engine damage.
Why Choose This Product
Upgrade your engine's reliability with a Cometic seal that combines OEM-level precision with enhanced durability. This single-piece solution saves time during maintenance while delivering consistent performance under demanding riding conditions. Trusted by mechanics and riders alike for its leak-proof sealing and long-term cost-effectiveness.| SKU | GM51C0DEEB |
|---|---|
| MPN | C9531 |
| UPC/GTIN | 191070060558 |
| Brand | Cometic |
| Category | Gaskets/Seals |
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Featured Review
| Make | Model | Years |
|---|---|---|
| Harley-Davidson | Panhead Big Twin | 1948-1965 |
| Harley-Davidson | Shovelhead Big Twin | 1966-1984 |
| Harley-Davidson | Evolution Big Twin | 1984-1999 |
Frequently Asked Questions
It is designed for Harley-Davidson Panhead, Shovelhead, and Evolution Big Twin engines. Because Harley engine variations exist within those families, confirm fitment by matching the OEM part number and engine location of the seal in your service manual or with a retailer’s fitment guide before ordering.
C9531 is typically sold as an individual seal, not a complete gasket kit. If you are doing a full engine or top-end rebuild you may want a full Cometic gasket kit in addition to this seal.
General hand tools are usually sufficient, but depending on where this seal is located, you may need pullers, seal drivers, or alignment tools recommended in the Harley-Davidson service manual for Panhead, Shovelhead, or Evo big twins.
Follow the factory service manual and Cometic’s general guidelines. Many modern Cometic seals are designed to seal dry or with only a light film of oil. Using heavy RTV where it is not specified can cause improper seating or contamination.
Cometic is a premium aftermarket gasket manufacturer; their seals generally meet or exceed OEM specifications and are designed for high-performance and durable sealing. However, the performance difference vs. OEM depends on engine condition and installation quality.
Installation Guide
Difficulty
Medium
Pro Tips
- Obtain and follow the factory Harley-Davidson service manual or a reputable aftermarket manual for the specific Panhead, Shovelhead, or Evo Big Twin model you are working on.
- Take clear photos before disassembly so you can confirm orientation and assembly order when re-installing.
- Use a plastic scraper or non-marring tool to remove old gasket/seal material and avoid gouging aluminum surfaces.
- Dry-fit the new seal first to ensure it matches the old piece in diameter, thickness, and profile before final installation.
- Inspect related components (bearing surfaces, shafts, covers) and replace worn parts while you have the engine opened.
Common Mistakes to Avoid
- Not positively identifying the exact sealing location and orientation before removal of the old seal.
- Reusing old, damaged, or contaminated gasket surfaces rather than cleaning and inspecting properly.
- Using excessive RTV or sealant where the manufacturer intended a dry or very light sealant application.
- Not verifying that the mating surfaces are flat and free of scratches, corrosion, or burrs before installation.
- Over-tightening related fasteners (covers, cases, etc.) and distorting the seal or gasket surface.
Comparison vs Stock/OEM
Cometic gaskets and seals are generally manufactured to meet or exceed OEM standards and are widely used in performance and racing Harley engines. The C9531 seal is intended as a direct replacement for the OEM Harley Big Twin seal at this location.
Improvements
- High-quality materials and manufacturing tolerances for consistent sealing.
- Designed to withstand heat and vibration found in Harley Big Twin engines.
- Often chosen by engine builders for performance and durability compared to generic aftermarket seals.
Considerations
- Performance benefits over a fresh OEM seal may be modest; the biggest advantages are quality control and availability.
- Proper installation and correct surface prep are critical—most sealing issues are due to installation or surface defects rather than the seal itself.
Durability & Warranty
Warranty
Typical Cometic limited manufacturer’s warranty against defects in materials and workmanship (duration and terms vary by seller).
Maintenance
Inspect for oil leaks during regular service intervals. If any seepage or leaks develop at the seal location, investigate alignment, crankcase breathing issues, and surface condition in addition to the seal itself.
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