Service manual

181 CID (3.0L) 4 CYLINDER GM ENGINE
SERVICE MANUAL NUMBER 26
90-861329--1 MARCH 1999 Page 3A-45
Checking Clearances
To obtain accurate measurements while using Plastigage, or its equivalent, engine must be
out of the boat and upside down so crankshaft will rest on the upper bearings and total clear-
ance can be measured between lower bearing and journal.
To ensure the proper seating of the crankshaft, all bearing cap bolts should be at their speci-
fied torque. In addition, prior to checking fit of bearings, the surface of the crankshaft journal
and bearing should be wiped clean of oil.
1. With the oil pan and oil pump removed, remove bearing cap and wipe oil from journal
and bearing cap to be inspected.
2. Place a piece of gauging plastic the full width of the bearing (parallel to the crankshaft)
on the journal as shown.
72558
a
b
a-Gauging Plastic
b-Journal
3. Install the bearing cap and evenly torque the retaining bolts to specifications. Bearing
cap MUST be torqued to specification in order to ensure proper reading. Variations in
torque affect the compression of the plastic gauge.
IMPORTANT: Do not rotate the crankshaft while the gauging plastic is between the
bearing and journal.
4. Remove bearing cap. The flattened gauging plastic will be found adhering to either the
bearing cap or journal.
Index