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Cast Iron Piston Rings

Description & Features

Groove Depth	Grooves must be at least 0.015 inches deeper than the maximum radial wall thickness of the piston ring with a tolerance of +0.003/-0 inches. This is to avoid any possibility of the ring bottoming in the groove when the ring is compressed to its working diameter.
Groove Width	To permit the ring to slide freely into the groove, the groove must be at least 0.001 inches wider than the maximum piston ring width with a tolerance of +0.003/-0 inches.
Materials	Cast Iron.
Radial Clearance	The radial clearance between the cylinder bore and piston should be less than 1/3 of the radial wall thickness of the piston ring to ensure sealing effectiveness.

Products

Model Number	O.D.	Width (in)	Wall Thickness
SPR-4002 Cast Iron Piston Ring	4 in	0.187	0.135
SPR-6004 Cast Iron Piston Ring	6 in	0.311	0.199
SPR-7002 Cast Iron Piston Ring	7 in	0.249	0.236

Product Questions & Answers (1)

Question by: Stan M on Jun 26, 2025, 4:24 PM

What's the deal with needing extra space in the groove for these rings?

Answer by: Customer Support on Jun 27, 2025, 7:49 PM

Grooves must be a hair deeper than the ring thickness to keep the ring from bottoming out when squeezed. We're talking at least 0.015 inches, give or take a smidge.