Reinforced head gasket Audi RS3 RS Q3 TT RS 2.5 CEPA CEPB CTSA CZGA CZGB

The Audi and Donkervoort engines covered

The 2.5-litre turbocharged five-cylinder, built as CEPA, CEPB, CTSA, CZGA and CZGB, powers the Audi RS3, RS Q3 and TT RS and the Donkervoort D8 models listed below.

The original gasket is numbered 07K 103 383 L. The manufacturer publishes neither its bore, nor its construction, nor its thickness. It is sized for standard combustion pressure: when that pressure increases, the clamping force drops, the head lifts and coolant reaches a cylinder.

Reinforced cylinder head gaskets

The seal does not depend on the gasket alone: it also depends on the bolts or studs that press the head against the block. With the O-Ring the roles are shared: the stainless ring seals the combustion chamber by itself, the body handles the water and oil circuits, and the block needs no machining.

This page presents the part number from Athena, an Italian maker of racing gaskets, in a single construction: the O-Ring, a steel sheet faced with aramid fibre and surrounded by a stainless ring. Its bore is 84 mm and its thickness 1.40 mm. It is customary to choose a gasket bore at least 0.5 mm larger than the cylinders. The part number is sold individually, one gasket per engine.

Technical specifications

The volume of a gasket is the space it keeps free above each cylinder. It is added to the combustion chamber and lowers the compression ratio; only gaskets of the same bore can be compared with each other.

Preparation and fitting

Before fitting, check the flatness of the head and block with a straight edge, and have them resurfaced if needed. Athena supplies the gasket ready to fit: apply no sealing paste.

Technical guide

The construction offered

Athena O-Ring A steel sheet clad in asbestos-free aramid fibre, in which every cylinder is surrounded by a stainless compression ring. The ring carries the clamping load onto a thin band, where the seal is decided, while a silicone bead separates the water and oil circuits. Of the whole range, it is the construction that best withstands high pressures.

Choosing bore and thickness

Gasket bore. The Athena O-Ring exists in 84 mm (330072R), in that bore only.

Thickness. The manufacturer does not give the thickness of the original gasket. A thicker gasket enlarges the combustion chamber and lowers the compression ratio; a thinner one reduces it and raises the ratio.

Without a published original thickness, read with a dial gauge how far the pistons stand above the block, above all if the removed gasket measures more than 1.40 mm: that value gives the clearance left between piston and head.

The brand

Athena S.p.A., an Italian maker of gaskets and engine parts, is based in Alonte, in Veneto, where its head office and main plant stand. The group also has sites in Spain, the United States, Brazil and India. Its multilayer gaskets are fitted as original equipment by carmakers, and its whole racing range is designed and built in Italy.

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: 07K 103 383 L.

Important: the part number on this page is reserved for the CEPA, CEPB, CTSA, CZGA and CZGB engines: check your vehicle's engine code before ordering.

Why switch to a reinforced gasket?

When the standard gasket reaches its limit, the reinforced gasket replaces it: at higher combustion pressure, it keeps its shape instead of being crushed.

On a boosted engine pushed by more aggressive mapping or a larger turbo, the head gasket is the first link of the top end to give way. A reinforced gasket rules out the leak, and the head removal that follows it, which costs far more than the gasket itself.