Reinforced cylinder head gasket Toyota 3K 4K

The Toyota engines covered

The Toyota 3K (1.2 litre) and 4K (1.3 litre) petrol engines, with their 3K-B, 3K-C, 3K-H and 4K-C variants, power the Corolla, Starlet, Liteace and Kijang models listed below.

The original gaskets carry part numbers 11115-22010 (3K and 3K-C), 11115-13010 (3K-H) and 11115-13031 (4K and 4K-C). Toyota publishes neither their bore, nor their thickness, nor their construction. Sized for standard combustion pressure, they no longer suffice once it rises: the clamping force drops, the cylinder head lifts and coolant passes into a cylinder.

Reinforced cylinder head gaskets

The head gasket does not seal on its own: sealing also depends on the fasteners that clamp the head to the block. Pure copper at 99.9% resists corrosion well, deforms without breaking and conducts heat well, without becoming brittle at high temperature.

This page presents part number C4105-043 from Cometic, an American maker specialising in racing gaskets, in a single construction: copper. Its bore is 84 mm and its thickness 1.09 mm. A gasket bore at least 0.5 mm larger than the actual cylinder bore is generally chosen. The part number is sold individually, one gasket per engine.

Technical specifications

The gasket volume is the free space it leaves above each cylinder. It adds to the combustion chamber and lowers the compression ratio, the more so as the volume grows. Values are only comparable between gaskets of the same bore.

Preparation and fitting

Before fitting, check with a straight edge that the cylinder head and block are flat, and have them resurfaced if needed. Cometic carefully checks the flatness of its copper gaskets.

Technical guide

The construction offered

Choosing bore and thickness

Gasket bore. The Cometic copper gasket exists in 84 mm (C4105), in that bore only.

Thickness. Toyota gives no thickness figure for the original gasket. The thicker the gasket, the larger the combustion chamber and the lower the compression ratio; the thinner it is, the higher the ratio climbs.

With no published original thickness, use a dial gauge to measure how far the pistons stand above the block face, especially if the removed gasket is thicker than 1.09 mm: this value gives the clearance left between piston and cylinder head.

The brand

Cometic Gasket, Inc. is an American maker of gaskets and engine sealing solutions, founded in 1989 in Concord, Ohio. Its reputation comes from the made-to-order gasket, cut to the bore and thickness required. All production stays 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 84 mm bore of the gasket offered 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: 11115-22010, 11115-13010 and 11115-13031.

Important: the part number on this page suits the 3K, 3K-B, 3K-C, 3K-H, 4K and 4K-C engines: check your vehicle's engine code before ordering.

Why switch to a reinforced gasket?

The copper gasket is meant to hold when the original gasket reaches its limit: pure copper is ductile and does not turn brittle in the heat, which keeps the seal between cylinder head and block.

Once a turbo or supercharger is added, or the compression ratio raised, the head gasket becomes the most fragile part of the top end. Opting for a reinforced gasket is then about prevention more than comfort: it spares you the leak and the cylinder head removal that follows.