NANO

130

ENGINE 273 MPFI

•

Big-end thrust clearance:

Check the big end of each connecting rod for thrust

clearance, with the rod fitted and connected to its crank

pin in the normal manner. If the clearance measured

is found to exceed the limit, the connecting rod or the

crankshaft, whichever is responsible for the exces-

sive clearance, must be replaced.

SR. ITEM STD VALUE

LIMIT

a Axial Play 0.05 to 0.35 mm 0.4

•

Connecting rod alignment :

Mount the connecting rod on the aligner to check it for

bow and twist and, if the limit is exceeded, replace it.

Ensure that connecting rod big end and small end

axes are parallel to each other and are within speci-

fied limits. Ensure that centre distance between small

end to big end is maintained within specified limit.

Install connecting rod bearing caps without bearing

shells on connecting rod.

Tighten connecting rod bearing cap mounting nuts to

specified torque.

Ensure that identification numbers for connecting rod

and connecting rod bearing cap are matched and

notches for bearing shells are on the same side.

Check twist and bend of connecting rod by using new

piston pin in connecting rod small end.

Measure twists and bends of connecting rod with feeler

gauge with respect to vertical face of connecting rod

alignment gauge in vertical and horizontal plane at a

distance of 50 mm from line joining centers of

connecting rod small end and big end bosses.

If necessary, straighten connecting rod in cold condi-

tion. Since a slight clearance exists between connect-

ing rod bolts and corresponding connecting rod bear-

ing cap holes, it is possible that connecting rod bear-

ing cap once removed may be installed off center, by

which dimension of connecting rod big end parent bore

will be different in different directions. If there is a dif-

ference noticed in connecting rod big

end parent bore dimension, connecting rod bearing

cap can be centralized by lightly tapping it with mallet

in required direction after slightly loosening connect-

ing rod bearing cap mounting nuts.

SR. ITEM

STD VALUE LIMIT

a Limit on Bow

(at 50mm)

0.03 mm 0.05

b Limit on twist

(at 50mm)

0.05 mm 0.1

Connecting Rod Small End :

Inspect the small end of each connecting rod for wear

and evidence of crack or any other damage, paying

particular attention to the condition of its bush. Check

the piston pin clearance in the small end. Replace the

connecting rod if its small end is badly worn or

damaged or if the clearance exceeds the limit.