Pontiac FIREBIRD 1972 Service Manual page 549

SIX CYLINDER ENGINE 6-37
PLASTIC GAGE METHOD OF DETERMINING
CONNECTING ROD BEARING CLEARANCE
Remove the cap of the bearing to be checked. Wipe
the bearing and the crankpin free of oil.
Place a piece of plastic gage, the length of the bearing
(parallel to the crankshaft), on the crankpin or bear-
ing surface (Fig. 6-56). Install the cap and tighten cap
bolts 35 lb. ft. (Do not turn crankshaft with plastic
gage in place).
Remove bearing cap and using plastic gage scale on
envelope, measure width of compressed plastic gage
before removing it from the crankpin or bearing (Fig.
6-57). If the bearing clearance is between .0005" and
.0025", the clearance is satisfactory. If the clearance
is more than .002Sn, replace the bearing with the next
undersize bearing and recheck clearance. Bearings
are available in standard, .001" and .002" undersize.
Rotate the crankshaft after bearing adjustment to be
sure bearings are not tight.
Check connecting rod end clearance between con-
necting rod cap and side of crankpin (Fig. 6-58).
Clearance should be .008"
-
.014". If clearance is
more than .014", replace connecting rod.
Fig. 6-58 Checking Connecting Rod Side Clearance
11. Carefully remove connecting rod and piston assem-
bly by pushing out with knurled handle of long guide.
CONNECTING ROD AND PISTON
ASSEMBLY
REMOVE
Remove rocker arm cover.
Loosen rocker arm nuts, rotate rocker arms and
remove push rods.
Remove coil and push rod covers.
Remove valve lifters.
Disconnect fuel line and vacuum line at carburetor.
Remove cylinder head, intake and exhaust manifolds
as an assembly. Remove spark plugs.
Raise Vehicle.
Remove oil pan.
Check connecting rod and piston for cylinder number
identification and if necessary, mark them.
Remove bearing cap and install connecting rod bolt
guide set J-5239.
CONNECTING ROD AND PISTON
DISASSEMBLE
CAUTION: Use care at all times when handling
and servicing connecting rods and pistons. To
prevent possible damage to these units, do not
clamp rod or piston in vise since they may
become distorted. Do not allowpistons to strike
against one another, against hard objects or
bench surfaces, since distortion of piston con-
tour or nicks in the soft aluminum m a t e d
may result.
1. Remove piston rings using suitable piston ring
remover.
'
.
2. Install pilot of piston pin removing and installing tool
J-9510 on piston pin.
3.. Install piston and connecting rod assembly on sup-
port and place assembly in an arbor press (Fig. 6-59).
Press pin out of connecting rod.
4. Remove assembly from press, remove piston pin from
support and remove tool from piston and rod.