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II. Engine Component Description
Piston Sizing
Pistons are matched during assembly to the
liner sleeve bore internal diameter dimensions.
The number stamped on top of the piston
represents the last four digits of that pistons
part number.
The letter stamped in the piston should match
the letter stamped on the block deck surface.
(If it doesnt, the piston has been replaced.)
The 4IRJ7N engine uses replaceable cylinder
liners. A kit containing a new piston and liner
is used when servicing engines under
warranty. This liner and piston kit needs to be
sized according to the number stamped on the
block.