Operation CHARM: Car repair manuals for everyone.
Manuals through 2025 now available!

Our trusted friends have launched a new website named LEMON, which has newer manuals. It also contains all the CHARM manuals.

LEMON is the spiritual successor to CHARM, I recommend you try it!

Link: lemon-manuals.la or lemon-manuals.org.ua

(Some people have issue connecting. LEMON is investigating. For now, use Firefox or change your DNS server)

Or, hide this message: temporarily or permanently

Piston Ring

Compression Ring (Top) to Ring Groove Clearance 0.04 - 0.072 Millimeter (mm)
Compression Ring (Bottom) to Ring Groove Clearance 0.30 - 0.50 Millimeter (mm)
Oil Ring (Steel Rail) Clearance 0.40 - 1.40 Millimeter (mm)
Ring Gap Compression (Top) 0.20 - 0.25 Millimeter (mm)
Compression (Bottom) 0.012 - 0.020 Inch (in)
Oil ring (Steel Rail) 0.016 - 0.035 Inch (in)
Ring Width Upper Compression Ring 0.011811 - 0.019685 Inch (in)
Lower Compression Ring 0.011811 - 0.019685 Inch (in)
Oil Control Ring 0.015748 - 0.055118 Inch (in)