Dodge 2001 Ram 1500 Owner's Manual page 1355

9 - 208 ENGINE 8.0L
HYDRAULIC LIFTERS (Continued)
Fig. 37 Tappets, Aligning Yoke and Yoke Retaining
1 - TAPPET ALIGNING YOLK
2 - YOKE RETAINING SPIDER
3 - TAPPET
CLEANING
Clean tappet with a suitable solvent. Rinse in hot
water and blow dry with a clean shop rag or com-
pressed air.
INSTALLATION
(1) Lubricate tappets.
(2) Install tappets in their original positions.
Ensure that the oil bleed hole (if so equipped)
faces forward.
(3) Install tappet aligning yokes. Position the yoke
retainer spider over the tappet aligning yokes (Fig.
37)Install the yoke retaining spider bolts and tighten
to 22 N·m (16 ft. lbs.) torque.
(4) Install the push rods in their original location.
(5) Install the rocker arms (Refer to 9 - ENGINE/
CYLINDER HEAD/ROCKER ARM / ADJUSTER
ASSY - INSTALLATION).
(6) Install lower and upper intake manifold (Refer
to 9 - ENGINE/MANIFOLDS/INTAKE MANIFOLD -
INSTALLATION).
(7) The cylinder head cover gasket can be used
again. Install the gasket onto the head rail. For the
left side the number tab is at the front of
engine with the number up. For the right side
the number tab is at the rear of engine with the
number up.
Spider
(8) Install cylinder head cover (Refer to 9 -
ENGINE/CYLINDER
COVER(S) - INSTALLATION).
(9) Install the air cleaner.
CAUTION: To prevent damage to valve mechanism,
engine must not be run above fast idle until all
hydraulic tappets have filled with oil and have
become quiet.
(10) Connect the negative cable to the battery.
(11) Road test vehicle and check for leaks.
PISTON & CONNECTING ROD
DESCRIPTION
The pistons (Fig. 38) are elliptically turned so that
the diameter at the pin boss is less than its diameter
across the thrust face. This allows for expansion
under normal operating conditions. Under operating
temperatures, expansion forces the pin bosses away
from each other, causing the piston to assume a more
nearly round shape.
All pistons are machined to the same weight,
regardless of size, to maintain piston balance.
The piston pin rotates in the piston only and is
retained by the press interference fit of the piston
pin in the connecting rod.
The pistons have a unique dry-film lubricant coat-
ing baked onto the skirts to reduce friction. The
lubricant is particularly effective during engine
break-in, but with time, the material becomes embed-
ded into cylinder bore walls and continues to reduce
friction.
The pistons are LH and RH bank specific.
STANDARD PROCEDURE—PISTON FITTING
Piston and cylinder wall must be clean and dry.
Specified clearance between the piston and the cylin-
der wall is 0.013-0.038 mm (0.0005-0.0015 inch). The
max. allowable clearance is 0.0762 mm (0.003 in.).
Piston diameter should be measured at the top of
skirt, 90° to piston pin axis. Cylinder bores should be
measured halfway down the cylinder bore and trans-
verse to the engine crankshaft center line.
Pistons and cylinder bores should be measured at
normal room temperature, 21°C (70°F).
(1) To correctly select the proper size piston, a cyl-
inder bore gauge, capable of reading in.0001 INCRE-
MENTS is required (Fig. 39). If a bore gauge is not
available, do not use an inside micrometer.The coat-
ing material is applied to the piston after the final
piston machining process. Measuring the outside
diameter of a coated piston will not provide accurate
results. Therefore measuring the inside diameter of
the cylinder bore with a dial Bore Gauge is MANDA-
BR/BE
HEAD/CYLINDER HEAD