5150 AutoSport Head Gasket & Head Stud Kit, BMW N54

Cut-Ring Head Gasket:

The Athena Cut Ring Head Gasket is designed as a direct replacement for BMW part # 11127557265 and 11127557266, specifically for use in N52 and N54 turbocharged inline-six engines. These engines can be found in a variety of models including the 135i, 335i, 535i, Z4 sDrive35i, X6 xDrive35i, and Alpina B3 Bi-Turbo.

Standard OEM & MLS gaskets can only handle a certain amount of cylinder pressures before they start to leak, making the Athena Cut Ring Head Gasket the recommended choice for applications making 16+ psi.

A compression leak passing the head gasket can cause a range of issues, including engine overheating, loss of power, misfires, and in severe cases, catastrophic engine failure.

Athena's gasket is crafted with premium quality reinforced M0115, an asbestos-free material that's original equipment approved and renowned for its superior quality. The AISI 304 stainless steel Cooper Rings bite into the aluminum head, providing maximum sealing capabilities around the cylinder bore and optimizing engine performance, even on engines with nitrous and/or turbo applications that exceed 2 bar boost.

Before installation, it is crucial to have the mating surfaces of the cylinder head and block professionally cleaned and resurfaced to ensure they are completely flat.

Please be aware that the gasket  should have a size that is 0.5mm to 1mm larger than the piston. For example, if the piston measures 84mm, then the gasket should be the next size up, either 84.5mm or 85mm.

MLX Head Gasket:

The Cometic MLX Head Gasket is designed as a direct replacement for BMW part # 11127557265 and 11127557266, specifically for use in N54B30 turbocharged inline-six engines. These engines can be found in a variety of models including the 135i, 335i, 535i, Z4 sDrive35i, X6 xDrive35i, and Alpina B3 Bi-Turbo.

The factory head gasket specifications for the N54 are 85mm bore and 0.048 inches thickness.

Composed of multiple layers of embossed coated and uncoated stainless steel, MLX gaskets are specially designed to conform to the surfaces of the cylinder head and engine block on the first heat cycle, creating a chemical bond via Cometic's proprietary coatings. These coatings provide a micro-seal for fluids against the head and block surface. 

The layers of the MLX gasket act as a spring, protecting against blowout and increasing active seal height by compensating for increased head lift. 

MLX Head Gaskets are different from MLS because they feature an extra,specialized 'stopper' fold-over layer. This layer provides a torque limiting surface that prevents yielding of the combustion seal. 

It's important to note that MLS/MLX head gaskets are not compatible with engines that have O-rings or receiver grooves around the cylinder bores. These gaskets require smooth and flat surfaces to seal properly.

Head Gasket Installation Instructions:

1. Make sure that the engine block and cylinder head surfaces are clean, flat, and free from any debris, oil, or coolant.

2. Install the head gasket on the engine block and ensure that it is properly aligned. Avoid twisting or bending the gasket during installation.

3. Place the cylinder head on top of the gasket and install the head bolts or studs in their correct positions.

4. Follow the manufacturer's recommended torque specifications and tighten the bolts or studs in the proper sequence to ensure even clamping force across the gasket.

5. After the initial tightening, re-torque the head bolts or studs after the engine has been started and then allowed to cool to room temperature. This will ensure that the gasket is properly seated and compressed.

6. It is recommended to not use any additional sealant on the head gasket, as it is already coated with a Viton rubber sealant. Using additional sealant can hinder the performance of the gasket.