Reinforced head gasket Fiat Uno Punto GT 1.4 Turbo 146A8 176A4 176B6

The Fiat engines covered

The 1.4 litre petrol engines listed in the table below, mostly turbocharged, power the Fiat Uno and Punto GT. Each takes a single cylinder head gasket.

The original gasket of these engines carries part number 71753170. Fiat 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 moves away from the block and coolant reaches a cylinder.

Reinforced cylinder head gaskets

Sealing does not rest on the gasket alone: the fasteners that press the head onto the block contribute just as much. With the O-Ring, the stainless steel wire seals the combustion chamber on its own while the gasket body closes the water and oil circuits; with the MLS, the 301 stainless steel sheets withstand 517 N/mm², 5 times the stress at which a composite gasket crushes for good, and spring back with every combustion.

This page brings together four part numbers from Athena, an Italian maker of competition gaskets, in two constructions: the O-Ring, a steel sheet faced with aramid fibre and ringed with a stainless steel wire, and the MLS, a stack of stainless steel sheets. The bores offered run from 81.5 to 82.5 mm, with thicknesses from 1.3 to 1.8 mm. As a rule, choose a gasket bore at least 0.5 mm larger than the cylinders. Each part number is sold individually: one gasket per engine.

Technical specifications

Gasket volume is the free room it leaves above each piston. It adds to the combustion chamber and lowers the compression ratio; compare only gaskets of equal bore, since the three bores on this page differ.

Preparation and fitting

Before fitting, lay a straight edge across the head and the block to check their flatness, then have them resurfaced if needed. Athena supplies its gaskets ready to fit: add no sealing paste.

Technical guide

The two constructions offered

Athena O-Ring A steel sheet faced with asbestos-free aramid fibre, with a stainless steel compression ring set around each cylinder. The ring concentrates the clamping load on a thin band, where the seal is made, while a silicone bead protects the water and oil passages. Because the combustion seal is carried by the ring and not by the gasket body alone, it is the construction that withstands the highest pressures in the range. It is supplied ready to fit, with no sealant to add.

Athena MLS Two to five layers of AISI 301 stainless steel, laser cut, stamped and riveted. Around each cylinder, a layer folded over on itself, the Gas Stopper, concentrates the clamping load on the combustion chamber, while beads seal the water and oil passages. The outer layers receive a two-coat finish: the first withstands high temperatures and fills small irregularities on the block and cylinder head, the second, silicone based, keeps the gasket from sticking on disassembly. This is Athena's all-steel choice, from a prepared naturally aspirated engine to moderate forced induction; beyond that, the O-Ring remains the construction that withstands the highest pressures.

Choosing bore and thickness

Gasket bore. The Athena O-Ring comes in 81.5 mm (330003R) and 82 mm (330010R), the Athena MLS in 82.5 mm (338005R and 338006R).

Thickness. Fiat publishes no thickness 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.

With the original thickness left unstated, use a dial gauge to measure how far the pistons stand proud of the block's gasket face, especially if you aim for 1.3 mm: it sets the clearance left between piston and head.

The brand

Athena S.p.A. is an Italian company specialising in gaskets and engine parts. Its head office and main plant are in Alonte, in the Veneto; it also runs sites in Spain, the United States, Brazil and India. Car makers fit its multi-layer gaskets as original equipment, and the whole competition range is designed and produced 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 bores of the gaskets offered (81.5 to 82.5 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: 71753170.

Important: the part numbers on this page only apply to the 146A8.000, 146A8.046, 176A4.000 and 176B6.000 engines: note your vehicle's engine code before ordering.

Why switch to a reinforced gasket?

Once the original gasket reaches its limit, the reinforced gasket takes over: at higher combustion pressure it does not crush and keeps its shape.

On a turbo engine given more boost or a higher compression ratio, the head gasket becomes the first weak point of the top end. A reinforced gasket rules out the leak, and the head removal that follows, far dearer than the part.