Chrysler RAM TRUCK 2500 1994 Service Manual page 871

9 - 1 5 0 5 . 9 L (DIESEL) ENGINE
Measure the diameter of the rod journal at the lo­
cation shown (Fig. 7). Calculate the average diameter
for each side of the journal.
The clearance is the difference between the con­
necting rod bore (smallest diameter) and the average
diameter for each side of the crankshaft journal.
M I N .
6 8 . 9 6 2 mm ( 2 . 7 1 5 inch)
MAX.
6 9 . 0 1 3 mm ( 2 . 7 1 7 inch)
Out-of-Round - Max.
0 . 0 5 0 mm ( 0 . 0 0 2 inch)
Taper - Max.
0 . 0 1 3 mm ( 0 . 0 0 0 5 inch)
Bearing Clearance - Max.
0 . 0 8 9 mm ( 0 . 0 0 3 5 inch)
J 9 1 0 9 - 9 1
Fig. 7 Connecting Rod Journal Diameter Limits
I f the crankshaft is within limits, replace the bear­
ing. I f the crankshaft is out of limits, grind the
crankshaft to the next smaller size and use oversize
rod bearings.
PISTON GRADING
When rebuilding an engine with the original cylin­
der block, crankshaft and pistons, make sure the pis­
tons are installed i n the original cylinder. I f replacing
the piston(s), make sure the replacement piston(s)
are the same grade as the original piston. I f a new
cylinder block or crankshaft is used, the piston grad­
ing procedure MUST be performed to determine the
proper piston grade for each cylinder.
(1) Install the connecting rod and piston assembly
into the N o . l cylinder. DO NOT install the piston
rings.
(2) Install the upper bearing shell i n the connect­
ing rod with the tang of the bearing i n the slot of the
connecting rod. The connecting rod bearing shells
must be installed i n the original connecting rod and
cap. Use clean lubricating oil to coat the inside diam­
eter of the connecting rod bearing shell.
(3) Install the bearing shell i n the connecting rod
cap with the tang of the bearing i n the slot to the
cap. Use clean lubricating oil to coat the inside diam­
eter of the bearing shell.
(4) The four digit number stamped on the connect­
ing rod and cap at the parting line must match and
be installed on the oil cooler side of the engine. I n ­
stall the connecting rod cap and capscrews. Tighten
the capscrews to 3 5 N-m (26 ft. lbs.) torque.
(5) Use a fine grit home to remove any burrs from
the cylinder block head deck. Zero the dial indicator
to the cylinder block head deck.
(6) Move the dial indicator over the piston directly
over the piston pin to eliminate any side-to-side
movement.
(7) Rotate the crankshaft to top dead center (TDC).
Rotate the crankshaft clockwise and counterclockwise
to find the highest dial indicator reading. Record the
reading.
(8) Remove the piston and connecting rod assembly
from the N o . l cylinder and install the assembly into
the No.2 cylinder. Repeat the procedure for every cyl­
inder using the same piston and connecting rod as­
sembly.
(9) Determine the grade of the piston being used
by referring to the Piston Grading Chart. Four digits
on top of the piston are the last four digits of the
part number.
ASSEMBLE
(1) Be sure the FRONT marking on the piston and
the numbers on the rod and cap are oriented (Fig. 8).
Install the retaining ring into the pin groove on the
FRONT side of the piston.
(2) Lubricate the pin and bore with engine oil.
(3) Install the piston pin i n the opposite side of the
installed retaining pin. Pistons do not require heat­
ing to install the pin, however, the piston does need
to be at room temperature or above.
(4) Determine the piston diameter and obtain the
appropriate ring set. The piston rings can be identi­
fied as shown i n Fig. 9.
(5) Position each ring i n the cylinder and use a pis­
ton to square i t with the bore at a depth of 89.0 mm
(3.5 inch) - (Fig. 10).