Caution
If replacement of the piston or con-rod is necessary on pistons with inserted con-rods, all components of this assembly (piston, piston rings, piston pins and con-rod) must be replaced with new components.
Assemble
Assemble guide drift from KM-634-6 (1), KM-634-7 (2) and KM-634-5 (3).
Insert new piston in woodruff key groove of KM-634-1 (1). The piston pin bore must be horizontal for this operation.
Mount Positioning Angle KM-634 (3) on KM-634-1. Only handtighten fastening bolts.
Clamp piston using Stop Plate KM-634-2 (2) so that it cannot rotate.
Adjust
Determine press-fit depth of piston pin.
Push assembly (1) comprising KM-634-6, KM-634-7 (length corresponds to that of piston pin) and KM-634-5 through piston pin bore and con-rod, until KM-634-7 is seated centrally in piston. In this position, the Positioning Angle KM-634-4 (2) must rest against the tip of the assembly (arrows, see illus. I) without any gap.
Tighten fastening bolts of positioning angle.
Install
Withdraw centre section of KM-634-7 from guide drift and replace with new (lubricated) piston pin.
Assemble
Heat upper con-rod eye of new con-rod with heater plate. Installation temperature: 280 ° C to 320 ° C. Place surface of eye flat on heater plate and reduce thermal conduction using fire-resistant brick (see illus. II).
Caution
As con-rods have no weight balancing studs, they cannot be reworked.
Installation position: Bead on con-rod (2) is located opposite arrow (1) on base of piston (see illus.).. Tight piston pin cannot be pushed further. Install quickly.
Assemble
Push assembly comprising KM-634-6, piston pin and KM-634-5 uniformly and without delay through piston pin bore and con-rod eye until it rests against Positioning Angle KM-634-4 (see illus.).
Install
Remove KM-634-5 and KM-634-6 from right and left side of piston pin and install piston with con-rod - see operation "Piston with Con-rod, Remove and Install".
