FRICTION MODIFIER

We investigate how piston rings can affect the amount of heat your engine generates.

- LAKE SPEED JR.

Sources

Joe Gibbs Racing: joegibbsracing.com

Total Seal: 632.587.7400; totalseal.com

Heat is a byproduct of combustion. Both air-cooled and water-cooled engines need to dissipate that heat to keep the engine from running too hot. Can piston rings play a role in managing that heat? Before we get into the details on that, we need to talk about another significant source of heat in an engine: friction.

Heat is also a byproduct of friction. Think about rubbing your hands together to warm them up. The faster you rub your hands together, the warmer they get. Now think about the pistons in your engine-they're moving faster than 200 cycles per second. That's why piston rings matter when it comes to engine temperature. 

The primary source of friction-related heat in an engine is from the piston rings rubbing against the cylinder wall. Multiple research studies from Ford and the U.S. Department of Energy have concluded that the piston ring and cylinder wall account for as much as 40% of all engine friction. No wonder today's OEM engines have thinner piston rings than their predecessors. Think about a 1972 Camaro and its 350ci small-block, which had a piston ring pack with two 5/64-inch rings and a 3/16-inch ring. Now think about the LS7, with two 1.2mm rings and a 3.0mm ring-that's a 40% reduction in overall ring thickness!

Ring Thickness vs. Engine Heat