Reinforced cylinder head gasket Ferrari 275 GTB/4 F226

The Ferrari engines covered

The Ferrari F226 engine, known as the Tipo 226, is a V12 of 3.3 litres that powers the Ferrari 275 GTB/4. Each engine takes two cylinder head gaskets, one per bank of cylinders.

The original gasket carries the Ferrari part number 9100151. The manufacturer publishes neither its bore, its construction nor its thickness. Designed for standard combustion pressure, it no longer suffices once that rises: the clamping force drops, the head lifts and coolant reaches a cylinder.

Reinforced cylinder head gaskets

Sealing a cylinder head is not down to the gasket alone: the studs and nuts that clamp each head to the block matter just as much. Check their condition and observe the specified tightening torque.

This page offers one part number from the American maker Cometic, a specialist in racing gaskets: H2092SPA043F. Its bore is 78 mm and its thickness 1.09 mm. The construction is not stated in the data consulted. Each engine needs two gaskets, one per bank of cylinders, that is two pieces of this same part number, sold individually.

Technical specifications

The volume of a gasket is the free space it leaves above each cylinder. This space adds to the combustion chamber and lowers the compression ratio; compare only gaskets of the same bore.

Preparation and fitting

Before refitting, lay a straight edge across each head and the block to check flatness, and have any warped surface machined.

Technical guide

The construction offered

Choosing bore and thickness

Gasket bore. The Cometic gasket H2092SPA043F is offered in 78 mm, with no other bore.

Thickness. The manufacturer gives no thickness for the original gasket of this engine: the removed gasket is the reference. A thicker gasket enlarges the chamber and lowers the compression ratio; a thinner one raises it.

As no original thickness is published, measure with a dial gauge how far the pistons protrude above the block face before fitting the 1.09 mm gasket: the value obtained gives the clearance left between piston and head.

The brand

Cometic Gasket, Inc. is an American company founded in 1989 in Concord, Ohio, that designs gaskets and sealing solutions for engines. Its reputation rests on the made-to-measure gasket, cut to the bore and thickness requested and built 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 78 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: not published by the manufacturer.

Important: the part number on this page suits the Ferrari F226 engine of the 275 GTB/4: each engine needs two pieces of H2092SPA043F, one per bank of cylinders.

Why switch to a reinforced gasket?

When the original gasket is no longer up to the job, the reinforced gasket takes over: the seal between each head and the block has to hold under a higher combustion pressure.

When an engine gains power, for example with a supercharger or turbo fitted later or a higher compression ratio, the head gasket is the first part to give way. A reinforced gasket prevents the leak, whereas removing both heads of a twelve-cylinder is long and costs far more than the gasket.