Reinforced cylinder head gasket Nissan MR16DDT and Renault M5M

The Nissan and Renault engines covered

The Nissan MR16DDT and the Renault M5M are two 1.6 litre petrol engines (1618 cm³) fitted to the Nissan Juke, Qashqai and X-Trail, the Renault Clio IV RS, Mégane IV and Talisman, and other models in the compatibility table.

The original MR16DDT gaskets carry the part numbers 11044-BV80A and 11044-1KC0A. The manufacturer publishes neither their construction nor their thickness, and their bore is 81 mm. Designed for standard combustion pressure, they lose clamping load when it rises: the head lifts and coolant reaches a cylinder.

Reinforced cylinder head gaskets

A head gasket does not seal alone: the seal depends on the fasteners that press the head onto the block. A composite gasket settles for good beyond 100 N/mm² of admissible stress, while the 301 stainless steel of MLX gaskets withstands 517 N/mm², 5 times more, and regains its shape at every combustion.

This page gathers the part numbers of Cometic, an American maker of racing gaskets, in a single construction: the MLX with its chamber stopper. The gasket bore is 81 mm, the same as the original gasket, and the thicknesses offered run from 0.71 to 1.37 mm, enough to adjust the compression ratio without touching the pistons or the cylinder head. As a rule, the gasket bore chosen is at least 0.5 mm larger than the actual cylinder bore. Each part number is sold individually, one gasket per engine.

Technical specifications

Gasket volume is the space it leaves above each cylinder. It adds to the combustion chamber and lowers the compression ratio the more, the larger it is. Only compare gaskets of the same bore.

Preparation and fitting

Before fitting, check the flatness of the head and block with a straight edge and have them skimmed if needed. No sealant is required: Cometic supplies these gaskets already coated.

Technical guide

The construction offered

Cometic MLX A stack of stainless steel layers whose centre layer is folded into a stopper around the combustion chamber, under a high-temperature coating. Clamping pressure rises where it is needed without adding to bore distortion. It is the most robust of the all-metal gaskets, for severe boost; it is offered here in 81 mm only.

Choosing bore and thickness

Gasket bore. The Cometic MLX comes in 81 mm only.

Thickness. The manufacturer does not publish the thickness of the original gaskets 11044-BV80A and 11044-1KC0A. A thicker gasket enlarges the combustion chamber and lowers the compression ratio; a thinner one reduces it and raises the ratio.

After any skimming of the block or head, use a dial gauge to measure how far the pistons stand proud of the block: this figure sets the clearance left between piston and head.

The brand

Founded in 1989 in Concord, Ohio, Cometic Gasket, Inc. designs gaskets and sealing solutions for engines. Its speciality is the made-to-order gasket, in the bore and thickness requested. Everything is made in the United States, from American materials.

Advantages over the original gasket

When a reinforced gasket becomes necessary

• Adding forced induction, or raising boost on an already turbocharged engine
• Cylinder rebored beyond what the 81 mm bore of the original gasket covers
• Looking for a compression ratio different from standard, higher or lower
• Engine that has already lost its gasket, or is consuming coolant
• Competition use, where the gasket goes through repeated temperature rises

Vehicle compatibility

OEM part number: 11044-BV80A and 11044-1KC0A.

Important: the part numbers on this page only suit the MR16DDT and M5M engines: check your vehicle's engine code before ordering.

Why switch to a reinforced gasket?

When the original gasket reaches its limit, the reinforced gasket stays in control: under higher combustion pressure it keeps its shape instead of settling.

When power goes up, with a turbo, a supercharger or a higher compression ratio, the head gasket is the first part of the top end to fail. A reinforced gasket beats a breakdown: it spares you the failure and the head removal that follows.