Glossary “heat affected zone” Definition:
A metal area that has been heated beyond its critical temperature, causing it to lose strength.

Glossary “heat control valve” Definition:
Thermostatically controlled valve in the exhaust manifold to divert heat to the intake manifold before the engine reaches normal operating temperature.

Glossary “heat crayons” Definition:
Used to determine the temperature of the aluminum or other metal being heated. They will melt at a specific temperature and warn you to prevent overheating.

Glossary “heat dam” Definition:
Narrow groove cut into the top of the piston. It restricts the flow of heat down into the piston.