Cometic Multi-layer Steel Head Gasket, BMW M20

This Cometic MLS Head Gasket is designed to replace BMW part numbers 11121722734, 11121722735, 11121722737, and 11121722738, specifically for the M20B20, M20B23, M20B25, and M20B27 engines. 

Cometic MLS Gaskets are composed of multiple layers of stainless steel, the number of layers used varying by application. These layers consist of both proprietary, high-temperature coated and uncoated stainless steel. Additional layers increase active seal height and can be used to fine-tune compression.

The specialized coating used on Cometic Gaskets conforms to the surfaces of the cylinder head and engine block on the first heat cycle, creating a chemical bond. MLS Gaskets are able to prevent blow-outs in engines with high cylinder pressure because the embossed layers act as a ‘spring’ and compensate for increased head lift. 

Please note, MLS head gaskets can NOT be used with motors that have O-rings or receiver grooves around the cylinder bores because they require smooth and flat surfaces to seal.

The M20B20 and M20B23 factory head gasket specifications are 80mm Bore with a thickness of 0.070 inches.

The M20B25 and M20B27 factory head gasket specifications are 84mm Bore with a thickness of 0.070 inches.

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 MLS 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 MLS gasket, as it is already coated with a Viton rubber sealant. Using additional sealant can hinder the performance of the gasket.