Chapter 2 Part D General engine overhaul procedures
20-27
BEARING
22.13 Tightening sequence for
the 3.OL V6 main bearing caps
(mono-block)
of the main bearing caps are difficult to remove, tap them gently from side- :-
22.15 Compare the width of the crushed Plastigage to the scale
on the envelope to determine the main bearing oil clearance
(always take the measurement at the widest point of the
Plastigagd); be sure to use the correct scale-standard and
metric ones are included
10 Before the crankshaft can be permanently installed, the main bearing
oil clearance must be checked.
11 Cut several pieces of the appropriate size Plastigage (they should be
slightlyshorterthanthewidthofthemain bearings)andplaceonepieceon
each crankshaft main bearing journal, parallel with the journal axis (see
illustration).
12 Clean the faces of the bearings in the caps and install the caps in their
original locations (don’t mix them up) with the arrows pointing toward the
front of the engine. Don’t disturb the Plastigage.
13 Starting with the center main and working out toward the ends, tighten
the main bearing cap bolts, in three steps, to the torque figure listed in this
Chapter’s Specifications. Don’t rotate the crankshaft at any time during
this operation. Note: On 3.OL V6 engines, torque bolts on the mono-block
in the proper sequence (see illtistration).
14 Remove the bolts and carefully lift off the main bearing caps. Keep
them in order. Don’t disturb the Plastigage or rotate the crankshaft. If any
to-side with a soft-face hammer to loosen them.
1.5 Compare the width of the crushed Plastigage on each journal to the
scale printed on the Plastigage envelope to obtain the main bearing oil
clearance (see ilk&ration). Check the Specifications at the keginning of
this Chapter to make sure it’s correct.
16 If the clearance is not as specified, the bearing inserts may be the
wrong size (which means different ones will be required). Before deciding
differentinsertsareneeded, makesurenodirtoroilwas betweenthe bear-
ing inserts and the caps or block when the clearance was measured. If the
Plastigagewaswideratoneendthan theother, thejournalmay betapered
(see Section 18).
17 Carefully scrape all traces of the Plastigage material off the main
bearing journals and/or the bearing faces. Use your fingernail or the edge
of a credit card -don’t nick or scratch the bearing faces.
Final crankshaft installation
18 Carefully lift the crankshaft out of the engine.
19 Clean the bearing faces in the block, then apply a thiq, uniform layerof
moly-base grease or engine assembly lube to each of the bearing sur-
faces. Be sure to coat the thrust faces as well as the journal face of the
thrust bearing.
20 Make sure the crankshaft journals are clean, then lay the crankshaft
back in place in the block.
21 Clean the faces of the,bearings in the caps, then apply lubricant to
them.
22 Install the caps in their original locations with the arrows pointing to-
ward the front of the engine. f
23 Install the bolts.
24 Tighten all except the thrust bearing cap bolts to the torque listed in
this Chapter’s Specifications (work from the center out and approach the
final torque in three steps).
25 Tighten the thrust bearing cap bolts to lo-to-12 ft-lbs.
26 Tap the ends of the crankshaft forward and backward with a lead or
brass hammer to line up the main bearing and crankshaft thrust surfaces.
27 Retighten all main bearing cap bolts to the torque listed in this Chap-
ter’s Specifications, starting with the center main and working out toward
the ends.
28 Rotate the crankshaft a number of times by hand to check for any ob-
vious binding.
29 The final step is to check the crankshaft endplay with feeler gauges or
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