Cometic C4311-040 MLS Cylinder Head Gasket for Honda K20 and K24 Engines

Why Choose a Cometic MLS Head Gasket?

Honda K-series engines have become popular platforms for performance builds because of their robust architecture, efficient cylinder heads, and extensive aftermarket support.

However, increasing compression or adding forced induction can place additional demands on the cylinder head sealing system.

The Cometic C4311-040 uses three stainless steel layers with embossed sealing features designed to distribute clamping pressure around the combustion chambers.

The outer layers incorporate a fluoroelastomer coating intended to accommodate microscopic surface irregularities, while the center layer helps establish the gasket’s compressed thickness.

When properly installed with compatible head fasteners and correctly prepared mating surfaces, this construction provides a durable sealing solution for K-series engine builds.

FYI: Understanding K20 vs. K24 Head Gasket Bore Sizes

Honda K20 engines typically use an 86mm factory cylinder bore, while many K24 engines use an 87mm factory cylinder bore.

The Cometic C4311-040 has an 87mm gasket opening, which makes measuring and verifying the engine’s actual bore particularly important.

An 87mm gasket opening may be appropriate for certain K20 applications, but gasket selection must also account for combustion chamber dimensions, coolant passages, and block-to-head compatibility.

For modified or sleeved K-series engines, verify the final bore and gasket opening before assembly.

Installation Recommendations

1. Verify the engine code and finished cylinder bore.
2. Inspect the cylinder head and block deck for warpage or damage.
3. Confirm that both mating surfaces meet Cometic’s MLS surface-finish requirements.
4. Clean the sealing surfaces thoroughly.
5. Check gasket alignment with the engine’s dowels and fluid passages.
6. Install the gasket according to the manufacturer’s instructions.
7. Use compatible cylinder head bolts or studs.
8. Follow the correct tightening sequence and fastener specifications.
9. Verify engine timing and complete reassembly.
10. Refill the cooling system and inspect for leaks.

Installation Tip: Avoid applying additional gasket sealants unless specifically instructed by Cometic.

Frequently Asked Questions

Does the Cometic C4311-040 fit a 2004 Acura RSX Type-S?

Yes. The 2004 RSX Type-S uses the K20A2 engine, one of the listed engine applications.

Will this gasket fit a 2006 Acura RSX Type-S?

Yes. The 2006 RSX Type-S uses the K20Z1 engine, which Cometic includes in the product’s engine compatibility.

Does it fit a 2004 Honda Civic Si?

Yes. The 2004 Civic Si uses the K20A3 engine.

Can I use this gasket on a K24 engine?

It is listed for the K24A1 engine. Do not assume it fits every K24 variant, since different K-series engine generations can require different gasket configurations.

Is this gasket suitable for turbocharged K-series builds?

It can be used in appropriately engineered forced-induction applications. Reliable sealing depends on cylinder pressure, head clamping, engine preparation, and tuning.

Does the package include head studs or bolts?

No. The package contains one MLS cylinder head gasket.

Build Your Honda K-Series Engine with Cometic

The Cometic C4311-040 MLS Head Gasket combines three-layer stainless steel construction, an 87mm bore, and .040-inch compressed thickness for compatible Honda K20 and K24 engines.

Whether you’re rebuilding a daily-driven Acura RSX or assembling a modified K-series performance engine, choosing the correct head gasket is essential for long-term reliability.

Shop Honda performance engine parts and replacement components at Pro Street Online.