86mm MLS Head Gasket .051 - Mits 4G63/4G63TB

The Cometic Gaskets 86mm MLS Head Gasket with 0.051-inch compression thickness is a multi-layer steel cylinder head gasket engineered specifically for Mitsubishi 4G63 and 4G63TB engines. This is a precision component designed for high-performance rebuilds where reliable sealing under elevated boost and cylinder pressure is non-negotiable. The 86-millimeter bore size matches the stock piston diameter of fourth-generation and turbocharged 4G63 variants found in tuner platforms like the Lancer Evolution and DSM platforms.

Multi-layer steel (MLS) construction provides superior conformability and reusability compared to older composite gasket materials. The 0.051-inch compression thickness is a critical specification—it defines the gasket's contribution to the engine's static compression ratio and must be matched to your head and block deck heights to achieve target CR. For 4G63 builds targeting higher boost levels or extended service intervals, MLS gaskets like this Cometic unit resist blow-by and coolant leakage under sustained load better than single-layer alternatives. The gasket's ability to handle thermal cycling without permanent set loss is essential in turbocharged applications where cylinder head temperatures regularly spike.

This gasket is the correct choice for engine rebuilds on stock-displacement 4G63 motors, stage 1 through stage 3 turbo upgrades, and naturally aspirated stroker builds. It's used in race engine assembly, street performance rebuilds, and comprehensive top-end refreshes where the cylinder head has been resurfaced or removed. Proper installation requires use of a calibrated torque wrench and adherence to Mitsubishi's head bolt sequence and torque specification for this engine family.