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)

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Piston Ring, Engine

Piston rings ring width compression top 1.47 - 1.49 Millimeter (mm)
Compression (bottom) 1.46 - 1.49 Millimeter (mm)
Ring gap compression (top) 0.25 - 0.28 Millimeter (mm)
Ring gap compression (bottom) 0.25 - 0.28 Millimeter (mm)
Ring Gap Oil Ring (steel rail) 0.04 - 1.68 Millimeter (mm)
Compression ring (top) to ring groove clearance 0.04 - 0.08 Millimeter (mm)
Compression ring (bottom) to ring groove clearance 0.06 - 0.09 Millimeter (mm)
Piston ring gaps (fitted) Upper compression ring 0.22 - 0.37 Millimeter (mm)
Lower compression ring 0.50 - 0.70 Millimeter (mm)
Oil scraper ring 0.15 - 0.66 Millimeter (mm)
Ring gap positions
The piston ring gaps must be spaced evenly around the circumference of the piston. This also applies to the elements of the oil scraper ring. Stagger the ring gaps at 120 deg. to one other