Cometic MLS Head Gasket for 97-01 Honda Prelude H22A4

Cometic MLS Head Gasket - 97-01 Honda Prelude (BB6) H22A4

The H22A4 is the most common H22 swap and boost platform for a reason. It revs, it breathes well, and it makes good power. What gives out first when you push it is usually the head gasket. On every firing stroke, combustion pressure pushes up on the head. The aluminum head and block also grow at slightly different rates as they heat up, so they shift against each other through every heat cycle. Add boost or high compression, and the extra cylinder pressure finds the weakest point of the gasket's seal. Once it gets past that seal, you're losing coolant into the cylinder or pushing combustion gas into the cooling system.

Cometic's MLS gasket holds that seal with layers of stainless steel instead of a composite sheet. It's built for a 97-01 Prelude's H22A4 that's going to see more cylinder pressure than Honda designed it for. That might be a turbo setup, a high-compression N/A build, or nitrous. If your engine's stock and you're just doing a head job, a quality OEM-style gasket is plenty. When the engine's making more power, the MLS is the one to use.

Built in Three Layers

The two outer layers are stainless, embossed with raised beads around each cylinder and fluid passage. Torque the head down and those beads compress like a spring, pushing back against the head and block. As the surfaces shift with heat, the beads spring back and keep the seal tight. The outer layers are coated in Viton, a fluoroelastomer rubber rated to 482°F (250°C). It fills tiny surface imperfections and helps seal the coolant and oil passages. Between them is a plain stainless shim, and its thickness sets the thickness of the whole gasket.

Even Clamping, No Re-Torque

A composite gasket compresses and settles after the first few heat cycles, which is why older engines often needed the head re-torqued after break-in. An MLS gasket spreads the clamp load evenly across the whole surface and doesn't settle, so it doesn't need re-torquing. Even clamping also means less bore distortion. The cylinders stay rounder when the head is torqued down, so the rings seal better.

Install Notes

MLS gaskets need flat, smooth surfaces to seal against. Have the head and block checked for flatness, and resurface them to Cometic's MLS surface finish spec if needed. Clean both surfaces down to bare metal, install the gasket dry, and torque the head in sequence to spec. If the engine's getting boost, swap the factory head bolts for head studs. They stretch less under load, so clamping force stays more consistent. Measure your bore before you order to make sure this gasket's bore matches your block.

Fitment

• 1997-2001 Honda Prelude (BB6) - H22A4
• 87mm gasket bore