RAM 1500 Truck 4WD V8-4.7L VIN N (2003)
Connecting Rod: Description and Operation
PISTON & CONNECTING ROD
DESCRIPTION
CAUTION: Do not use a metal stamp to mark connecting rods as damage may result, instead use ink or a scratch awl.
The pistons are made of a high strength aluminum alloy The anodized top ring groove and crown has been replaced with a coated top ring that is blue
in color on the bottom surface. Piston skirts are coated with a solid lubricant (Molykote) to reduce friction and provide scuff resistance. The
connecting rods are made of forged powdered metal, with a "fractured cap" design. A pressed fit piston pin is used to attach the piston and connecting
rod.
STANDARD PROCEDURE-PISTON FITTING
1. To correctly select the proper size piston, a cylinder bore gauge, capable of reading in 0.003 mm (0.0001 inch) INCREMENTS is required. If a
bore gauge is not available, do not use an inside micrometer.
2. Measure the inside diameter of the cylinder bore at a point 38.0 mm (1.5 inches) below top of bore. Start perpendicular (across or at 90 degrees)
to the axis of the crankshaft at point A and then take an additional bore reading 90 degrees to that at point B (Fig. 76).
3. The coated pistons will be serviced with the piston pin and connecting rod pre-assembled.
