The Ford Barn

ursus · 07-16-2010, 09:58 PM

I am rebuilding an engine with a set of NORS pistons and notice that the ring grooves were not as deep as the previous set. These are 0.0175 inches deep on the top two grooves and most of the pistons I have around here are 0.195 to 0.210 inches deep. I have also notices some variation in the cross section thickness of the various rings, everything from 0.175 down to 0.155 inches thick, some with 0.020 thick expanders behind a 0.140 thick oil control ring. All of these were designed for the 28-34 A/B engines.

Any thoughts about how much of a gap there should be between the inner surface of the ring and the inner radius of the groove? Thanks much.

07-16-2010, 09:58 PM	#1
ursus Senior Member Join Date: May 2010 Location: Oregon Posts: 1,375	Piston Ring Clearance I am rebuilding an engine with a set of NORS pistons and notice that the ring grooves were not as deep as the previous set. These are 0.0175 inches deep on the top two grooves and most of the pistons I have around here are 0.195 to 0.210 inches deep. I have also notices some variation in the cross section thickness of the various rings, everything from 0.175 down to 0.155 inches thick, some with 0.020 thick expanders behind a 0.140 thick oil control ring. All of these were designed for the 28-34 A/B engines. Any thoughts about how much of a gap there should be between the inner surface of the ring and the inner radius of the groove? Thanks much.