What is the function of a fire ring in a head gasket?

The function of a fire ring in a head gasket is to contain heat and pressure. Fire rings are typically made from metal and are designed to provide a strong seal around combustion chambers. Their primary role is to prevent combustion gases from leaking into the coolant passages or the crankcase, which could lead to a loss of compression and possible engine damage.

By maintaining a tight seal under the extreme conditions of heat and pressure that exist in an engine's combustion chamber, fire rings help ensure efficient engine operation. This containment is crucial for maintaining performance and efficiency while also protecting the engine from damage that could result from leaks.