Reinforced head gasket Ferrari F106B Mondial

The Ferrari engines covered

The F106B is a Ferrari V8 petrol engine. It powers the Ferrari Mondial 8 and Mondial 2.9, including the convertible, listed in the compatibility table below.

The original gasket carries part number 168.946. Ferrari gives neither its bore, nor its thickness, nor its construction. The engine takes two cylinder head gaskets, one for each bank of cylinders, sized for the original combustion pressure; if that pressure rises, the clamping force fades, the head lifts a little and coolant finds its way into a cylinder.

Reinforced cylinder head gaskets

Sealing rests not on the gasket alone but also on the fasteners that clamp the head to the block. Above 100 N/mm², a composite gasket sets for good; the 301 stainless steel of MLS gaskets withstands 517 N/mm², 5 times more, and springs back at every combustion. Also inspect the head bolts and replace any that are stretched or damaged, on both cylinder heads.

This page brings together 3 Cometic part numbers, from the American maker of competition gaskets, for a single construction: MLS, multi-layer steel. Two bores are offered: 81 mm (C4430-045 and C4430-060) and 89 mm (C4395-045). The 81 mm bore comes in 1.14 mm and 1.52 mm; the 89 mm bore comes in 1.14 mm only. The engine takes two gaskets, one per bank of cylinders: order the quantity needed for both banks. The thicknesses offered let you adjust the compression ratio without touching the pistons or the cylinder head. 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 and for one cylinder bank only: one is needed on the right and one on the left.

Technical specifications

A gasket's volume is the free space it leaves above each cylinder; it adds to the combustion chamber and lowers the compression ratio. Compare only gaskets of the same bore: 81 or 89 mm here.

Preparation and fitting

Before reassembly, check the flatness of the head and block gasket faces with a straightedge and have them machined if necessary. Cometic gaskets come pre-coated: add no sealing paste. Also clean the gasket faces thoroughly before fitting, on each of the two cylinder heads.

Technical guide

The construction offered

Cometic MLS Several stainless steel layers, embossed and joined by rivets. Each outer layer carries active beads that trace every cylinder and every fluid passage. A moderate clamping load is enough to seal, and the bore distorts little. This all-round gasket covers everything from a tuned naturally aspirated engine to light boost. Every part number on this page comes in this construction. Here it serves both banks of cylinders of the Ferrari V8.

Choosing bore and thickness

Gasket bore. The Cometic MLS is offered in 81 mm (C4430-045 and C4430-060) and 89 mm (C4395-045).

Thickness. Ferrari does not state any thickness for the original gasket 168.946. A thicker gasket enlarges the combustion chamber and lowers the compression ratio; a thinner one reduces it and raises the ratio.

Before settling on a thickness below the original, read with a dial gauge how far the pistons protrude above the block's gasket face: it shows the clearance left between piston and head. On this V8, measure on each of the two banks of cylinders.

The brand

Cometic Gasket, Inc. is an American company set up in 1989 and based in Concord, Ohio, which designs and manufactures gaskets and sealing parts for engines. It made its name with custom gaskets, cut to the bore and thickness required, all produced in the United States from American materials. Its part numbers for these Ferrari engines are offered here in two bores.

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 and 89 mm bores of these gaskets 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: 168.946.

Important: the part numbers on this page suit only the F106B engine: check your Ferrari's engine code before ordering.

Why switch to a reinforced gasket?

Once the original gasket reaches its limits, the reinforced gasket takes over: under higher combustion pressure it holds its shape instead of crushing. For the Ferrari models on this page, it is the answer as soon as the engine exceeds its original output.

Turbo added, compression ratio raised or revs pushed with sharper camshafts: in every case the cylinder head gasket turns into the weak link of the top end. A reinforced gasket avoids the leak and the head removal that would follow, far costlier than the gasket. On these Ferrari engines it is the first point to deal with once the original output is exceeded.