Reinforced cylinder head gasket Opel Vectra A 1.6 C16NZ2

The Opel Vauxhall engines covered

The 1.6-litre C16NZ2 petrol engine, a 75 hp four-cylinder, powers the Opel Vectra A detailed below.

The original gasket carries part number 608 808. Opel publishes neither its bore, nor its thickness, nor its construction. It is calculated for the standard combustion pressure: when that rises, the clamping load fades, the cylinder head lifts off the block and coolant finds its way into a cylinder.

Reinforced cylinder head gaskets

The gasket does not provide the seal on its own: the fasteners that clamp the head against the block provide half of it. Above 100 N/mm² of stress, a composite gasket sags for good; the 301 stainless steel of MLS gaskets withstands up to 517 N/mm², 5 times more, and returns to its shape at each combustion.

This page presents the Cometic part number, an American maker of competition gaskets, in a single construction: MLS. Bore of 82 mm, thickness of 2.03 mm. By convention, the gasket bore exceeds the cylinder bore by at least 0.5 mm. It is sold individually, one gasket per engine.

Technical specifications

A gasket's volume is the space it leaves clear above each cylinder. This space adds to the combustion chamber and lowers the compression ratio; only gaskets of the same bore can be compared.

Preparation and fitting

Before assembly, check with a straight edge that the cylinder head and block are flat, and have them machined if necessary. Cometic delivers this gasket already coated: add no sealing paste.

Technical guide

The construction offered

Cometic MLS Multi-layer steel: several embossed stainless sheets, laid one on another and riveted together. The outer sheets carry active beads around each cylinder and each fluid passage. A moderate tightening torque is enough to seal and the bore distorts little. A versatile gasket, from the tuned naturally aspirated engine to moderate forced induction.

Choosing bore and thickness

Gasket bore. The Cometic MLS gasket comes in 82 mm (H1568080S), with no other bore.

Thickness. Opel gives no thickness figure for 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, use a dial gauge to measure by how much the pistons stand proud of the block face, especially if the removed gasket is thinner than 2.03 mm: the reading gives the free distance between piston and cylinder head.

The brand

Cometic Gasket, Inc. is a US firm specialising in gaskets and sealing parts for engines, founded in 1989 in Concord, Ohio. Its reputation rests on the made-to-order gasket, cut to the bore and thickness ordered, and on production carried out entirely in the United States, using local 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 82 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: 608 808.

Important: the part number on this page suits the C16NZ2 engine: check your vehicle's engine code before ordering.

Why switch to a reinforced gasket?

When the original gasket reaches its limits, the reinforced gasket takes over: under higher combustion pressure it does not crush and keeps its shape.

A turbo, a supercharger or a raised compression ratio put the head gasket to the test first, the weak link of the top end. A reinforced gasket prevents the leak, and so the head removal that follows, a job far costlier than the gasket itself.