sealing · FF-0338

What is a fire ring, and would fire rings allow a bigger bore on a 21-stud Flathead?

As Steve understands it, a shallow groove is cut around the cylinder in the block and a matching one in the head, and a ring of usually copper wire is sandwiched between them, normally with a head gasket as well. He thinks it could work on a stock bore, but the six o'clock stud still limits it: as the bore grows toward 60 or 100 thousandths over, the ledge left for the groove gets very thin.

Expert

Steve Coppock

Evidence

expert attributed

Component

fire rings

Applicable scope

1932–1937 Ford Flathead V8, 21-stud