Section 6 - 2
Azalea Aviation Copyright 2014
movement in the piston. Slide the wrist pin partially out of the piston allowing
room for the rod. Insure the orientation at which the piston will be installed onto
the connecting rod. Practice installing the pin properly while the rod is cool
because once you heat it up and install it you have one chance to get it right
without having to use a press.
The piston has an arrow marking on the top which should always point to
the propeller or flange end on the engine. In the case above with rod #1 the arrow
will point to the right. On rod #2 it will point to the left, and so on. Using the torch
slowly heat up the small end of the rod until it starts to turn a light brownish color.
(Fig 3) Quickly insert the piston (in correct orientation) and slide the wrist pin it
until it hits the guide. Hold this position for a few seconds as the rod cools down
and locks the wrist pin in place. (Fig 4) Check for freedom of movement of the
piston. The wrist pin should be centered on the rod. If the pin locks in off center
then a press may be needed to move the pin. Be very careful using a press to not
damage the piston.
Remove the Piston/Rod from the vise once cool and proceed to the next set. Do not
slap the rod against the piston skirt at any time. Always check the arrow direction
on the pistons that they correspond correctly to the numbered rod and installation.
Fig. 2 – Rod Clamped into vise
