Reinforced head gasket Nissan 5.6 V8 VK56DE

The Nissan engines covered

The VK56DE petrol engine, a 5.6 litre thirty-two valve V8, powers the Infiniti QX56 and the Nissan Armada, Pathfinder III, Patrol VI and Titan models in the compatibility table below. It takes two cylinder head gaskets, one per cylinder bank.

The original gaskets carry the part numbers 11044-7S002 and 11044-7S007. Nissan publishes neither their bore, nor their thickness, nor their construction. They are calibrated for the standard combustion pressure: when it rises, the clamping load fades, the cylinder head lifts and coolant gets into a cylinder.

Reinforced cylinder head gaskets

Sealing does not rest on the head gasket alone: it also depends on the fasteners, which clamp the head onto the block. A composite gasket is permanently crushed beyond 100 N/mm² of allowable stress; the 301 stainless steel of MLX/MLS gaskets withstands 517 N/mm², 5 times more, and springs back at every combustion.

This page presents the part numbers of the American maker Cometic, a specialist in competition gaskets, in two constructions: the MLS with a 100 mm bore (C4922-040 and C4923-040) and the MLX with chamber stopper and a 102.7 mm bore (C4610-040 and C4609-040). The thickness is 1.02 mm in both cases. A V8 takes one gasket per cylinder bank: order two gaskets per engine. Each part number is sold individually.

Technical specifications

A gasket's volume is the free space it keeps above each cylinder. It adds to the combustion chamber and lowers the compression ratio accordingly. Since the two constructions do not share the same bore, set their volumes side by side with care: only gaskets of equal bore compare directly.

Preparation and fitting

Before fitting, check with a straight edge that the head and the block are flat, and have them resurfaced if necessary. Cometic supplies its gaskets already coated: no sealing paste is needed.

Technical guide

The two constructions offered

	Cometic MLS Stainless steel sheets, stamped, stacked and riveted together. The outer sheets have beads that surround each cylinder and each fluid passage. Moderate tightening is enough to seal and the bore distorts little. A versatile construction, from the tuned naturally aspirated engine to moderate forced induction.
	Cometic MLX A multilayer stainless steel gasket whose folded centre sheet forms a stopper around each chamber. This stopper carries the clamping pressure to the bore and limits how far the gasket is crushed. This construction targets forced induction engines and high combustion pressures.

Choosing bore and thickness

Gasket bore. The Cometic MLS is available here in 100 mm (C4922-040 and C4923-040) and the MLX in 102.7 mm (C4610-040 and C4609-040).

Thickness. No thickness is stated by Nissan for the original gaskets. A thicker gasket enlarges the combustion chamber and lowers the compression ratio; a thinner one reduces it and raises the ratio.

Because the original thickness is not known, measure with a dial gauge how much the pistons stand proud of the block face, particularly after resurfacing: that figure determines the piston-to-head clearance.

The brand

Cometic Gasket, Inc. is an American company founded in 1989 in Concord, Ohio, which designs gaskets and sealing solutions for engines. Its reputation rests on made-to-measure gaskets, cut to the bore and thickness required, and on production that is entirely American, from domestic 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 bore of the gasket offered (100 mm for the MLS, 102.7 mm for the MLX) 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: 11044-7S002 and 11044-7S007.

Important: the part numbers on this page suit only the VK56DE engine, which takes two gaskets, one per cylinder bank: check your vehicle's engine code before ordering.

Why switch to a reinforced gasket?

When the original gasket reaches its limits, the reinforced gasket steps in: under higher combustion pressure, it keeps its shape instead of sagging.

As soon as power increases, through a turbo, a supercharger or a higher compression ratio, the head gasket is the first link in the top end to fail. Choosing a reinforced gasket preserves the engine: it spares you the breakdown and the cylinder head removal that goes with it.