Reinforced cylinder head gasket Ford 2.3 C23HD0D N38H N48H

The Ford engines covered

The 2.3 litre (2,261 cc) Ford EcoBoost petrol engines C23HD0D, N38H and N48H are fitted to the Everest II, Mustang and Zenos E10 models listed below.

These engines receive two original gaskets: part number 2172426 (C23HD0D), with an 88.5 mm bore, and part number EJ7E-6051-HA (N38H and N48H), with an 89 mm bore. Ford publishes neither their construction nor their thickness. They are designed for standard combustion pressure: when that pressure rises, the clamping load weakens, the cylinder head lifts and coolant seeps into a cylinder.

Reinforced cylinder head gaskets

A cylinder head does not seal through the gasket alone: the fasteners, which press the head against the block, do half the job. Past 100 N/mm², a composite gasket is crushed with no recovery; the 301 stainless steel of MLS gaskets holds up to 517 N/mm², 5 times more, and springs back after every combustion.

This page presents the part number from Athena, an Italian maker of racing gaskets, for a single construction: the multi-layer steel MLS. The gasket has an 89 mm bore, against 88.5 and 89 mm for the original gaskets, and a thickness of 1.30 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

Gasket volume is the space it leaves free above each cylinder. It is added to that of the combustion chamber and so lowers the compression ratio. Only gaskets of the same bore can be compared on this point.

Preparation and fitting

Before fitting, check with a straight edge that the cylinder head and the block are flat, and have them machined if needed. Athena supplies the gasket already coated: do not add any sealing paste.

Technical guide

The construction offered

Athena MLS Two to five layers of AISI 301 stainless steel, laser cut, then stamped and riveted together. Around each cylinder, a folded layer forms a Gas Stopper that concentrates the clamping force on the combustion chamber, while beads close off the water and oil circuits. Each outer face receives two coatings: the first withstands high temperatures and fills small irregularities in the block and cylinder head, the second, in silicone, keeps the gasket from sticking when it is taken off. Athena made it its all-steel solution, from a prepared naturally aspirated engine to moderate forced induction.

Choosing bore and thickness

Gasket bore. The Athena MLS is offered in 89 mm (338482R), in that bore only.

Thickness. Ford does not publish the thickness of the original gaskets. 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, especially if the removed gasket is thicker than 1.30 mm: that value gives the clearance left between piston and head.

The brand

An Italian maker of gaskets and engine components, Athena S.p.A. has its head office and main plant in Alonte, in the Veneto. It also runs sites in Spain, the United States, Brazil and India. Its multi-layer gaskets are fitted as original equipment by car makers, and its entire competition range is designed and made 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 bore of the original gaskets, 88.5 and 89 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: 2172426 and EJ7E-6051-HA.

Important: the part number on this page fits only the engines C23HD0D, N38H and N48H: check your vehicle's engine code before placing an order.

Why switch to a reinforced gasket?

Where the original gasket has reached its limits, the reinforced gasket keeps holding: under higher combustion pressure it does not sag and retains its geometry.

As soon as a turbo, a supercharger or a higher compression ratio pushes power up, the head gasket becomes the most exposed part of the top end. Choosing a reinforced gasket means protecting yourself against a leak and the cylinder head removal that comes with it.