The sealing capabilities of the Ford Piston Ring are what help to minimize the leakage past the pistons from the extreme force placed upon it. On all Ford engines there are two distinctive types of piston rings. Each type serves a separate but important purpose.
The two upper Ford piston rings are in place to hold back the compression that is generated in the combustion chamber. When inspecting either the old or the new ones, it should be noticed that the beveled edge is facing the combustion chamber. This is the best way for sealing the moving joint of the piston and the cylinder in your Ford engine.
Below the compression rings is a three piece oil ring. This is the piston ring that prevents the oil from the crank case from entering the combustion chamber but still makes it possible to lubricate the moving piston in the cylinder.
All of the piston rings are made with a slit in them. This makes it possible to expand the ring and slip it over the piston so they can be put into place in the grooves on the side of the pistons. Each one of the slits must be positioned differently so they do not line up and make it possible for the compression or oil to leak past them because of the slight openings.
Because of the friction that is created between the piston rings and the cylinder walls, the rings will wear over time. If the oil in not changed on a regular schedule, this wear occurs prematurely and causes the need for an engine rebuild to occur before its time on your Ford vehicle. This is one of the reasons an owner should always perform the scheduled periodical maintenance procedures on time every time.