cylinder heads · FF-0162

Why is the Flathead spark plug placed next to the exhaust valve?

Steve says the plug holes are offset to the exhaust side because that is the hottest area, where the charge would ignite anyway; putting the plug there gives one combustion event, not two. He also explains compression ratio and the trade-off in a Flathead chamber: a smaller chamber raises compression but restricts flow and valve opening, and too much brings pre-ignition.

Expert

Steve Coppock

Evidence

expert attributed

Component

combustion chamber and spark plug location

Applicable scope

Ford Flathead V8 cylinder heads