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Randall C
Randall C, ASE Master Tech
Category: Chevy
Satisfied Customers: 12890
Experience:  ASE Master, L1, 32 years, Diagnostic / Electrical Specialist
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Metro: you tell me what the plastigauge clearenc is

Resolved Question:

can you tell me what the plastigauge clearenc is on a 1997 geo metro 1000cc crankshaft and rod bearings
Submitted: 8 years ago.
Category: Chevy
Expert:  Randall C replied 8 years ago.

Hello, the accepetable clearances are noted below. The limit the the maximum clearance allowed.


Connecting rod bearings:


Bearing Clearance

Standard 0.020-0.050 mm (0.0008-0.0019 inch)
Limit 0.080 mm (0.0031 inch)




Main bearings;



Standard 0.020-0.040 mm (0.0008-0.0015 inch)
Limit 0.060 mm (0.0023 inch)




CAUTION: Do not turn crankshaft while plastic-type gaging material is installed. Damage to crankshaft journals and/or main bearing housings could occur.


  1. Place a piece of plastic-type gaging material the full width of the main bearing (parallel to the crankshaft) on the journal, avoiding the oil hole.
  2. Install the main bearing cap. When installing each main bearing cap to the cylinder block, point the arrow mark toward the crankshaft pulley side and install each cap from crankshaft pulley side to flywheel side in order 1, 2, 3 and 4. Gradual and uniform tightening is important for main bearing bolts. Main bearing caps must be torqued to specification in order to insure proper reading. Tighten main bearing cap bolts to54 Nm (40 ft. lbs.) .

  1. Remove the main bearing cap and, using the scale on the plastic-type gaging material envelope, measure the plastic-type gaging material width at its widest point. Standard main bearing clearance is 0.020 to 0.040 mm (0.0008 to 0.0015 inch) . If the clearance exceeds the main bearing clearance limit of 0.060 mm (0.0023 inch) , replace the bearing. Always replace both upper and lower inserts as a unit. A new standard bearing may produce proper clearance. If not, it will be necessary to regrind for undersize bearing. After selecting new bearing, recheck the clearance.






  1. Before checking bearing clearance, clean the bearing and the crank pin.
  2. Install the bearing in the connecting rod and the connecting rod cap.
  3. Place a piece of plastic-type gaging material the full width of the crankshaft as contacted by bearing (parallel to the crankshaft), avoiding the oil hole.

CAUTION: When installing the cap, be sure to point the arrow mark on the cap to the crankshaft pulley side. DO NOT turn the crankshaft with plastic-type gaging material installed, or damage could occur.
  1. Install the connecting rod bearing cap to connecting rod; secure with; two connecting rod bearing cap nuts. Tighten connecting rod bearing cap nuts to 35 Nm (26 ft. lbs.) .

  1. Remove the cap and using the scale on the plastic envelope, measure the plastic-type gaging material width at the widest point. Standard bearing clearance is0.020 to 0.050 mm (0.0008 to 0.0019 inch) . If the clearance exceeds the limit of0.080 mm (0.0031 inch) , use a new standard size bearing and remeasure the clearance.


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