Reinforced head gasket Nissan 4.5 VK45DE

The Nissan engines covered

The VK45DE is a 4.5 litre V8 petrol engine, fitted to the Infiniti FX45, M45 and Q45 as well as the Nissan Cima, Fuga, Gloria and President and the Mitsuoka Galue in the compatibility table below. Each of its two cylinder banks takes its own cylinder head gasket.

Two original gaskets are listed: 11044-AR008 and 11044-AR003. Nissan does not publish their bore, thickness or construction. They are sized for standard combustion pressure; beyond it they compress and a leak appears between the cylinder and the cooling circuit.

Reinforced cylinder head gaskets

The gasket is not enough on its own: the fasteners that press the cylinder head onto the block supply the other half of the seal. A composite gasket settles permanently above 100 N/mm² of stress; the 301 stainless steel of MLS gaskets withstands up to 517 N/mm², 5 times more, and springs back with each combustion.

This page gathers 36 Cometic part numbers, from an American maker of competition gaskets, all in MLS construction, a stack of stainless steel sheets. The C4486 (left bank) and the C4485 (right bank) each come in 18 thicknesses, from 0.69 to 3.56 mm, with a single bore of 93.5 mm. One engine takes two gaskets: one per cylinder bank.

Technical specifications

Gasket volume is the space left free above each piston once the head is torqued down. It is added to the combustion chamber and reduces the compression ratio, so a thicker gasket lowers it further; compare only gaskets of the same bore.

Preparation and fitting

Before fitting, check the flatness of the cylinder head and block with a straight edge, and have them resurfaced if necessary. Cometic gaskets are supplied already coated: do not apply any sealant.

Technical guide

The construction offered

Cometic MLS An assembly of stamped, riveted stainless steel sheets. The outer sheets carry active beads around each cylinder and each coolant or oil passage. A moderate tightening torque is enough to seal, and the bore distorts very little. This construction suits a tuned naturally aspirated engine as well as moderate boost.

Choosing bore and thickness

Gasket bore. The Cometic MLS gasket is offered here in 93.5 mm, for the left bank (C4486) as well as the right bank (C4485).

Thickness. Nissan does not state the thickness of its original gaskets. A thicker gasket enlarges the combustion chamber and lowers the compression ratio; a thinner one reduces it and raises the ratio.

Since Nissan states no original thickness, use a dial gauge to read how far the pistons protrude above the block's gasket face, especially if you aim for a thickness near 0.69 mm: this reading gives the free clearance between piston and cylinder head.

The brand

Cometic Gasket, Inc. was founded in 1989 in Concord, Ohio, and specialised in gaskets and sealing parts for engines. Its reputation rests on made-to-order gaskets, cut to the requested bore and thickness, and on an entirely American manufacture, from local 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 93.5 mm bore of the gaskets offered 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-AR008 and 11044-AR003.

Important: the part numbers on this page only suit the VK45DE engine; the C4486 fits the left bank and the C4485 the right bank: order one part number per bank and check your vehicle's engine code before ordering.

Why switch to a reinforced gasket?

When the original gasket reaches the end of its capacity, the reinforced gasket takes over: exposed to a higher combustion pressure, it keeps its shape instead of being crushed.

Turbo, supercharger or a higher compression ratio: whichever it is, the head gasket is the first part to fail in the top end. A reinforced gasket avoids the leak and, above all, the head removal that follows it, which costs far more than the gasket.