Gaskets & Seals

Gaskets seal the joints of an engine, and the head gasket works hardest of all, sealing combustion pressure, coolant and oil between the block and the cylinder head. This category is mainly head gaskets, with complete engine gasket sets for rebuilds.

Head gaskets are listed by construction, bore and thickness:

• Multi-layer steel (MLS) gaskets use several embossed steel layers and are the usual choice for tuned and boosted engines.
• MLX is a related multi-layer design.
• Cut Ring gaskets add a solid ring around each bore.

The gasket bore must be at least as large as the cylinder, including any oversize. The thickness sets how high the head sits above the block, which changes the compression ratio and the clearances between piston, valves and head. So if the head or block has been skimmed, or the pistons are changing, work out the thickness you need rather than ordering the standard one.

MLS gaskets need flat, clean surfaces with a fine finish, so have the head and deck checked and machined if needed. Fit new head bolts or studs, since stretch bolts must not be reused, and follow the torque sequence and steps exactly. After a head gasket repair, change the coolant and oil, as both may have been contaminated. When the engine is apart, a complete gasket set is worth having, because the smaller seals have aged just as long.