Cometic MLS (Multi-Layer Steel) Head Gaskets
maximum sealing performance for today’s high output engines and require
no sealants. MLS gaskets are ideal for both aluminum heads to aluminum
blocks and aluminum heads to cast iron blocks. They can withstand the
shearing force created by the two materials. MLS gaskets have increased
strength because they are comprised of multiple layers of stainless
steel; which also creates the ability to rebound and resist corrosion.
The outer layers are embossed and coated on both sides with Viton (a
flouro-elastomer rubber based material that is heat resistant to 250 C/
482 F. Viton is designed to meet the demands of a variety of harsh
sealing environments, load conditions, and surface finishes. The center
or shim layer is uncoated stainless steel, which can be varied to
accommodate multiple thickness requirements.
What is MLS?
stands for Multi-Layer Steel. MLS head gaskets are comprised of three
or five layers of stainless spring steel. The outer layers are an
embossed Viton coated stainless steel providing a superior seal with
excellent rebound characteristics and are corrosive resistant. MLS head
gaskets reduce bore distortion and withstand extreme cylinder pressures.
The MLS design is also used in a superior line of exhaust
Can MLS head gaskets be used with motors setup with o-rings or receiver grooves around the cylinder bores?
MLS head gaskets require smooth, flat and true head and deck surfaces
to seal. Most of the time with o-ring setups the wire and groove fall
where our gasket’s combustion seal is located; therefore, the wire will
hold the gasket and not allow proper compression while the receiver
grooves allow combustion gases to escape.
What surface finish is required to us an MLS head gasket?
surface finish of 50 RA (roughness average) or finer, is recommended
for a proper gasket seal. Anything rougher may conflict with the gasket
What head bolt/stud torque do you recommend when using an MLS gasket?
using MLS head gaskets always refer to the manufacturer of the fastener
to determine accurate torque values. Appropriate torque is critical
when installing new gaskets of any kind.
Why does Cometic recommend MLS gaskets to be installed dry?
Multi-Layer Steel (MLS) head gaskets go on dry because they are coated
with a sealant. Each MLS head gasket is coated with a .001" thick Viton
rubber that is bonded to the outer stainless steel layers. Adding an
additional sealer can hinder the performance of an MLS head gasket.