Reinforced cylinder head gasket Renault 5 Super 5 9 11 18 19 21 1.4 847 C2J

The Renault engines covered

The 1.4 litre petrol engines on this page, with the codes 847 and C2J, power the Renault 5, Super 5, 9, 11, 18, 19, 21, Fuego, Rapid and Trafic in the table, from 1978 to 1994. With a single cylinder head, the gasket is sold individually: one is needed per engine.

The original gasket carries the part numbers 77 00 680 689, 77 00 705 406 and 77 01 349 331 according to the TecDoc parts database. The manufacturer 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 seal does not rest on the gasket alone: it also depends on the fasteners that clamp the head onto the block. A composite gasket crushes for good beyond 100 N/mm², whereas the 301 stainless steel of the MLS withstands 517 N/mm², 5 times more, and springs back with every combustion. With the O-Ring, the stainless ring isolates the combustion chamber on its own, and the gasket body closes the water and oil circuits. On these engines, new bolts at every refit limit head movement and leaks.

This page brings together the part numbers of the racing manufacturer Athena, in two constructions: the stainless-ring O-Ring and the multilayer MLS. Gasket bores run from 77 to 78 mm, with a single thickness of 1.8 mm. As a rule, the gasket bore chosen is at least 0.5 mm larger than the actual cylinder bore. Each part number is sold individually, one gasket per engine.

Technical specifications

The volume of a gasket is the space it leaves open above each cylinder. It adds to the combustion chamber: the larger it is, the lower the compression ratio. Compare these volumes only between gaskets of the same bore. Here, the bores offered run from 77 to 78 mm.

Preparation and fitting

Before fitting the gasket, check with a straightedge that the cylinder head and block are flat, and have them resurfaced if needed. There is no need to add sealant: Athena supplies its gaskets already coated. This check applies to all three part numbers on this page.

Technical guide

The two constructions offered

O-Ring / Cut Ring Athena A steel core covered with asbestos-free aramid fibre, with a stainless compression ring crimped around each cylinder. The ring concentrates the clamping load on a narrow band, exactly where the seal is decided, while a silicone bead protects the water and oil passages. It is the construction that best withstands high combustion pressures, intended for the most heavily stressed engines. On this page, it is part number 330009R, in 77.5 mm.

Athena MLS Two to five AISI 301 stainless steel sheets, laser-cut, embossed and then riveted. One of them is folded around each cylinder into a Gas Stopper that directs the clamping load towards the combustion chamber, while embossed ridges close the water and oil circuits. The outer faces are coated: one layer withstands heat and fills small flaws in the block and head, a silicone layer stops the gasket sticking when it is removed. It is Athena's all-steel solution, the one chosen for the tuned naturally aspirated engine as well as for moderate boost. On this page, these are part numbers 338249R, in 77 mm, and 338250R, in 78 mm.

Choosing bore and thickness

Gasket bore. The Athena O-Ring comes in 77.5 mm (330009R), the Athena MLS in 77 mm (338249R) and 78 mm (338250R).

Thickness. The manufacturer publishes no thickness for the original gasket of these Renault engines. 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 1.8 mm thickness.

The brand

Athena S.p.A. is an Italian company that designs gaskets and engine parts in Alonte, in the Veneto, where its head office and main factory are located. It also has sites in Spain, the United States, Brazil and India. Its multilayer gaskets are fitted as original equipment by car makers, and its entire competition range is designed and built in Italy. Part numbers 330009R, 338249R and 338250R 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 the gaskets offered (77 to 78 mm) 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: 77 00 680 689, 77 00 705 406, 77 01 349 331.

Important: the gaskets on this page are listed for the Renault models in the table, from 1978 to 1994. For any other vehicle, note the engine code before ordering.

Why switch to a reinforced gasket?

Once the original gasket reaches its limits, the reinforced one takes over: under higher combustion pressure it keeps its shape and does not crush. The Renault 847 and C2J engines get three part numbers here.

As soon as boost or the compression ratio goes up, the head gasket is the first part to give way in a built engine. A reinforced gasket prevents the leak, and the cylinder head removal that would follow: a job out of all proportion to the price of the part. This holds for the Renault models in the table as for any hard-driven engine.