Do I need to resurface the cylinder heads before using this gasket kit? | WTA Guide

Do I Need to Resurface the Cylinder Heads Before Using This Gasket Kit?

Choosing whether to resurface cylinder heads is critical for optimal gasket sealing. Professionals often ask, Do I need to resurface the cylinder heads before using this gasket kit? Knowing when resurfacing is necessary prevents leaks, ensures engine reliability, and supports warranty compliance.

Cylinder Head Flatness and Finish: Essential Requirements

- Why it matters:

- Proper cylinder head flatness and surface finish are vital for gasket sealing and engine longevity (Source: Fel-Pro Gaskets Tech Bulletin).

- Industry standard:

- Cylinder head flatness tolerance typically must not exceed 0.002 in (0.05 mm) within 6 inches (150 mm) (Source: ASE, Federal-Mogul).

- Surface roughness (RA):

- MLS (Multi-layer Steel) gasket: 30-60 microinches (0.75-1.5 microns).

- Composite gasket: 60-100 microinches (1.5-2.5 microns).

When Resurfacing is Required

- Visible Damage:

- Any warping, scratches, gouges, or corrosion on the sealing surface.

- Failed Previous Gasket:

- Overheating or a blown head gasket often distorts head flatness.

- Exceeding OEM Flatness:

- Always check with precision tools—resurface if OEM limits are exceeded.

- Switching Gasket Types:

- Upgrading from composite to MLS gaskets? Strict surface finish standards apply.

When Resurfacing May Not Be Needed

- No Overheat History:

- Engine has not severely overheated and passes flatness measurements.

- Surface is Intact:

- No scratches, corrosion, or material transfer from old gasket.

- Correct Surface Finish:

- Confirmed using a surface profilometer; within manufacturer spec.

Risks of Skipping Resurfacing

- Gasket Seal Failure:

- Inadequate surface finish or flatness can cause leaks and engine damage.

- Warranty Voidance:

- Many gasket manufacturers require documentation of proper surfacing for warranty support.

- Reduced Engine Life:

- Persistent leaks can quickly escalate to severe engine issues.

Best Practice: Inspection and Measurement

- Professional inspection:

- Use straightedges, feeler gauges, and surface finish testers.

- Follow Manufacturer Instructions:

- Refer to both engine and gasket kit manufacturer guidelines.

- Document Everything:

- Record measurements and any corrective action taken for service records and warranty.

Authoritative Sources

- Fel-Pro Tech Bulletins

- ASTM E527 Surface Finish Standards

- ASE Automotive Service Excellence Manuals

- OEM Cylinder Head Service Guides

Takeaway

Properly assessing whether you need to resurface cylinder heads before installing a gasket kit is essential for sealing reliability. Always inspect, measure, and adhere to OEM and gasket manufacturer guidelines for professional, leak-free results.