Cometic Honda K20/K24 87mm Head Gasket .040 inch MLS Head Gasket - C4311-040

Cometic MLS Head Gasket — Honda K20/K24, 87mm Bore, .040" (C4311-040)

A multi-layer steel head gasket built for high-output K-series engines, and the standard answer when a stock composite gasket won't hold cylinder pressure under boost.

MLS provides maximum sealing performance and requires no sealants. Multiple embossed layers of stainless steel give the gasket increased strength plus the ability to rebound and resist corrosion — that rebound is what keeps a seal alive through heat cycles rather than crushing once and staying crushed.

The outer layers are embossed and coated both sides with Viton, a fluoroelastomer rubber heat resistant to 250°C / 482°F, designed for harsh sealing environments, load conditions, and surface finishes. The center shim layer is uncoated stainless, and its thickness is what sets the compressed height.

Ideal for aluminum heads to aluminum blocks and aluminum heads to cast iron blocks — it withstands the shearing force created between two materials with different expansion rates.

Specs: 87mm bore, .040" compressed thickness, 3 layers, round bore, MLS construction. Made in USA.

Fitment: Honda K20A2, K20A3, K20Z1, K24A1 — 02-06 Acura RSX, 02-05 Civic Si, 02-14 CR-V, 03-07 Accord, 03-11 Element.

Two things to plan for. MLS gaskets need a good surface finish to seal — the deck and head should be flat and finished to spec, not just wiped clean. And thickness changes your compression ratio, so pick the gasket to your target rather than defaulting to .040". The .030" and .051" are the other options in this family.

Head studs are effectively required. An MLS gasket on stock head bolts under real boost is the most common reason people do this job twice.