Reinforced cylinder head gasket Opel Ascona Rekord Manta Kadett 2.0 20N 20S 20E

The Opel engines covered

The 2.0-litre four-cylinder petrol engines 20N, 20S and 20E, rated 90, 100 and 110 hp, power the Opel Ascona B, Rekord D and E, Manta B and Kadett C Coupé Rallye in the table, from 1975 to 1988. As the engine has a single head, the gasket is sold individually: one per engine.

The original gasket carries part number 6 07 971. Opel publishes neither its bore, nor its thickness, nor its construction. It is sized for standard combustion pressure: when that rises, the clamping load drops, the head lifts and coolant reaches a cylinder.

Reinforced cylinder head gaskets

The bolts that clamp the head to the block provide half of the sealing by themselves: the gasket cannot manage alone. A composite gasket is crushed for good from 100 N/mm², whereas the 301 stainless steel of the MLS gasket takes 517 N/mm², five times more, and recovers its shape at every combustion. This also concerns the Opel engines on this page.

This page brings together three part numbers from the racing manufacturer Athena, in multilayer MLS construction. Gasket bores run from 97 to 98 mm, for three thicknesses: 1.45, 1.5 and 1.8 mm.

Technical specifications

Gasket volume corresponds to the room the gasket creates above each cylinder. It is added to the combustion chamber and brings the compression ratio down; on this page, the bore as well as the thickness vary by part number, and the volume varies accordingly.

Preparation and fitting

Prior to installing the gasket, check the flatness of the head and block faces with a straight edge, and have them machined flat if required. The Athena gasket arrives already coated: add no sealing paste. This advice covers the three part numbers on this page.

Technical guide

The construction offered

Athena MLS A pile of two to five AISI 301 stainless steel sheets, laser cut, pressed and then riveted. A folded sheet, the Gas Stopper, surrounds each cylinder and directs the clamping load toward the combustion chamber; beads separate the water and oil circuits. The outer faces receive two coatings: the first resists heat and makes up for small flaws in the block and head, the second, in silicone, prevents the gasket from sticking at removal. It is Athena's all-steel answer, from the prepared naturally aspirated engine to moderate boost. On this page, these are part numbers 338239R, in 97 mm, 338298R, in 98 mm, and 338464R, in 97 mm.

Choosing bore and thickness

Gasket bore. The Athena MLS comes in 97 mm (338239R) at 1.45 mm, in 98 mm (338298R) at 1.5 mm, and in 97 mm (338464R) at 1.8 mm.

Thickness. The manufacturer publishes no thickness for the original gasket of these Opel models. A thicker gasket enlarges the combustion chamber and lowers the compression ratio; a thinner one reduces it and raises the ratio.

Since the original thickness is not published, measure with a dial gauge how far the pistons stand above the block deck: the figure shows the clearance left between piston and head with the 1.45, 1.5 and 1.8 mm thicknesses.

The brand

Athena S.p.A. designs and manufactures gaskets and sealing parts for engines. Based in Alonte, in the Veneto, with other sites in Spain, the United States, Brazil and India, the brand also supplies some car makers as original equipment. Its competition range is born entirely in Italy, from design to production. Part numbers 338239R, 338298R and 338464R are the ones on this page.

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 of original gasket 6 07 971, which Opel does not publish 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: 6 07 971.

Important: the gaskets on this page are listed for the Opel models in the table, from 1975 to 1988. For any other vehicle, note the 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 keeps its thickness and shape instead of being crushed. The Opel 20N, 20S and 20E engines get three part numbers here.

Fitting a turbo or supercharger, or raising the compression ratio: as soon as power climbs, the head gasket is the first link in the top end to give way. A reinforced gasket prevents the leak and the cylinder head removal that follows, far costlier than the gasket. This holds for the Opel models in the table as for any hard-driven engine.