NANO

140 / 1980

134
ENGINE 273 MPFI
• Check cylinder block for cracks by pressure testing
method.
• Clean cylinder bores, bearing surfaces, oil
passages in crank case thoroughly. Check water
jackets for leakages by blowing air at a pressure
of 5 bar & then dipping the cylinder block in the hot
water (temp of water 70 °C to 80 °C).
• The block with any leakages / cracks should be
discarded.
• Thoroughly clean main bearing caps and
corresponding machined surfaces of crank case.
Install main bearing caps without bearing shells in
their respective positions on crank case.
• Tighten main bearing cap mounting bolts to
specified torque.
• Check crank case main bearing parent bore
dimensions.
• Install new pairs of main bearing shells according
to size of crank shaft main bearing journal diameter,
making sure that securing lugs of bearing shells
are properly seated in grooves of crank case and
main bearing caps.
• Install main bearing caps with bearing shells in their
respective position on crank case.
• Tighten main bearing cap mounting bolts in
specified sequence to specified torque.
• Measure main bearing bore.
If main bearing parent bore dimension is
maintained within specified limits, proper main
bearing bore dimension is automatically achieved.
However, it must be physically measured and
confirmed.
Main bearing shells are precision finished and
should not be bored or scrapped.