TM 5-3805-260-24
BASIC BLOCK
MAIN BEARING BORES
With the main bearing caps installed and
tightened to the torque given in the chart TIGHTENING
PROCEDLIRE FOR THE BOLTS FOR NIAIN BEARING
CAPS. Check main bearing bore size using the 1 P3537
Gauging Group. If the main bearing bore is not x, within
3.7075 + .0015 in. (94. 171 + 0.038 mm), replace the
main bearing cap. It is necessary to line bore the
replacement service caps. See the topic LINE BORING
MAIN BEARING CAP.
When installing main bearing caps on
a
reconditioned engine, use new bearing cap bolts and
washers.
MAIN BEARING CAP GUIDE WIDTH
Check the width of the main bearing cap guide.
The guide width of a new cap is 6.5600 + .0007 in.
(166.624 + 0.018 mm). Replace main bearing caps that
are less than the minimum width of 6.5580 in. (166.573
mm). It is necessary to line bore the replacement service
caps. See the topic LINE BORING MAIN BEARING
CAP.
When installing main bearing caps on
a
reconditioned engine, use new main bearing cap bolts
and washers.
LINE BORING MAIN BEARING CAPS
When reconditioning a block, and one main
bearing cap is replaced, line bore the replaced cap. If it is
necessary to replace more than one cap, it is
recommended that all of the main bearing bores be line
bored. See the topic LINE BORING MAIN BEARING
BORES.
Clean bearing caps and saddles. Remove all
nicks from pan rail. Plug oil holes in block with grease to
prevent chips from entering oil passages.
CENTERING RINGS IN BLOCK
1. Centering rings. 2. Oiler
Place 1P2344 Centering Rings (1), with oiler (2)
up, on each side of the cap being replaced. For an end
cap, place 1P2344 Centering Rings (1) in the second
and fourth main bearing bores.
Mark new cap to correspond with number on saddle and
install the new unbored cap (5). Mark cap and saddle
"OS" for oversize next to location number. Tighten the
unbored cap bolts (4) to the torque shown in the chart
TIGHTENING PROCEDURE FOR THE BOLTS FOR
NIAIN BEARING CAPS. Place the original bearing caps
(3) over the centering rings (1). Tighten the original
bearing cap bolts (6) hand tight.
CENTERING RINGS INSTALLED
1. 1P2344 Centering Rings. 3. Original bearing caps.
4.
Bolts (two). 5. Unbored cap. 6. Bolts (four).
Oil boring bar (7) and insert it through centering
rings (1). Tighten bolts (6) to a minimum of 20 lb. ft. (25
N m) and a maximum of 50 lb. ft. (70 N. m) while
spinning boring bar (7) to check for binding. Centering
rings (1) must be seated in bearing saddles after
tightening.
INSTALLING BORING BAR
6. Bolts (four). 7. 1P2352 Boring Bar.
Bolt torsion bar assembly (8) loosely to opposite
end of block from which boring bar will be driven. Install
feed assembly (10) into boring bar and tighten setscrew
(9). Slide feed assembly (10) onto torsion bar assembly
(8) and tighten bolt ( I 1). Tighten bolt (12) finger tight.
Boring bar must slide in and out freely after these
tightening operations. Tighten thumbscrew (13).
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