Reinforced cylinder head gasket Toyota 7M-GE 7M-GTE 3.0L

The Toyota engines covered

The Toyota 7M-GE petrol engine, a six-cylinder of 3.0 litres with 24 valves, and its turbocharged 7M-GTE version power the Supra (A70) and the Cressida, Cresta, Chaser and Crown listed below. A single cylinder head covers all six cylinders: only one gasket is needed per engine.

The original part numbers from Toyota are 11115-42020, 11115-42021 and 11115-42041. Toyota publishes neither the bore, nor the thickness, nor the construction of the original gasket. That gasket is sized for standard pressure: once it rises, the clamping load relaxes, the head lifts and coolant reaches a cylinder.

Reinforced cylinder head gaskets

Sealing does not depend on the gasket alone: the fasteners that clamp the head to the block count just as much. A composite gasket settles permanently beyond 100 N/mm²; the 301 stainless steel of MLS 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 competition gaskets, in a single construction: MLS, multilayer steel. The gaskets come in two bores, 84 and 86 mm, and in thicknesses from 0.69 to 3.56 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

A gasket's volume is the space it leaves open above each cylinder. It adds to the volume of the combustion chamber and lowers the compression ratio by the same proportion. Compare only gaskets of the same bore.

Preparation and fitting

Before fitting, check with a straightedge that the gasket faces of the head and the block are flat, and have the warped one resurfaced. Apply no sealant: Cometic gaskets are supplied coated.

Technical guide

The construction offered

MLS Cometic A stack of stamped stainless steel sheets assembled with rivets. The outer sheets have active beads around each cylinder and each fluid passage. Moderate clamping is enough to seal and the bore distorts little. A versatile construction, from the tuned naturally aspirated engine to moderate forced induction.

Choosing bore and thickness

Gasket bore. The Cometic MLS is offered in an 84 mm bore (C4278) and in an 86 mm bore (C4275).

Thickness. No thickness is published by Toyota for the original gasket of these engines. A thicker gasket enlarges the combustion chamber and lowers the compression ratio; a thinner one reduces it and raises the ratio.

If you choose a thickness below the standard one, first measure with a dial gauge by how much the pistons protrude above the block face: this figure gives the clearance remaining between piston and head.

The brand

Cometic Gasket, Inc. is an American company established in Concord, Ohio, since 1989. It designs gaskets and sealing solutions for engines, and its reputation comes from the made-to-measure gasket, supplied at the bore and thickness requested. All production remains in the United States, from American raw 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 bore size of the original gasket, a figure Toyota keeps unpublished 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: 11115-42020, 11115-42021 and 11115-42041.

Important: the part numbers on this page match the Toyota 7M-GE and 7M-GTE engines listed above: note your vehicle's engine code, then pick the gasket bore (84 or 86 mm) suited to your cylinders before ordering.

Why switch to a reinforced gasket?

When the original gasket reaches its limit, the reinforced gasket replaces it: under higher combustion pressure, it holds its shape instead of being crushed.

With a turbocharger, a supercharger or a raised compression ratio, the cylinder head works harder and the gasket becomes the weak link of the top end. The reinforced gasket rules out a gas or coolant leak and the head removal that goes with it, with the vehicle off the road.