Reinforced head gasket Ford Puma 1.7 16V MHA MHB

The Ford engines covered

The MHA and MHB petrol engines, 1.7 litre four-cylinders with 16 valves, power the Ford Puma 1.7 16V and Puma Racing ST 160 listed below.

This original gasket carries the part numbers 1031000 and 97MF6051AA. Its bore is 81 mm; the manufacturer publishes neither its construction nor its thickness. It is calculated for standard combustion pressure: when that pressure climbs, the clamping force weakens, the cylinder head lifts and coolant finds its way into a cylinder.

Reinforced cylinder head gaskets

The head gasket does not seal on its own: the seal depends on the fasteners, which press the cylinder head against the block. Here, the stainless steel of the gasket is coated with rubber, which lets it follow the small irregularities of the mating surfaces.

This page offers the part number from Cometic, the American maker of competition gaskets, in a single construction: rubber coated stainless steel. Its bore reaches 83 mm, against 81 mm for the original gasket, and its thickness is 0.25 mm. As a rule, a gasket bore at least 0.5 mm larger than the real cylinder bore is chosen. The part number is sold individually, one gasket per engine.

Technical specifications

Gasket volume is the space the gasket leaves free above each cylinder. It adds to the combustion chamber and lowers the compression ratio, all the more as it grows. Values can only be compared at an equal gasket bore.

Preparation and fitting

Before fitting, run a straight edge across the cylinder head and the block to check their flatness, and have them resurfaced if needed. Cometic also checks the flatness of its gaskets.

Technical guide

The construction offered

Choosing bore and thickness

Gasket bore. The Cometic rubber coated stainless steel gasket is only offered here in 83 mm (C4223).

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

As the original thickness is not published, use a dial gauge to measure how far the pistons stand above the block, in particular if the removed gasket is thicker than 0.25 mm: that figure gives the clearance left between piston and cylinder head.

The brand

Cometic Gasket, Inc. is an American maker of gaskets and engine sealing solutions, founded in 1989 in Concord, Ohio. Its reputation comes from the made-to-measure gasket, cut to the bore and thickness wanted. Its production stays entirely in the United States, from American 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 81 mm bore of the original gasket 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: 1031000; 97MF6051AA.

Important: the part number on this page fits only the MHA and MHB engines: check your vehicle's engine code before ordering.

Why switch to a reinforced gasket?

The reinforced gasket is designed to hold where the original gasket reaches the end of its capacity: a stainless steel sheet with a rubber coating keeps its shape and preserves the seal between cylinder head and block.

Once a turbo or supercharger is added, or the compression ratio is raised, the head gasket becomes the weak point of the top end. Opting for a reinforced gasket is then about prudence more than comfort: it protects against a failure and the cylinder head removal that follows.