1988 PONTIAC FIERO Service Repair Manual

6A2-18 2.8 LITER V-6
Installation
Clean sealing surfaces on cylinder case and oil
pan.
Install gasket and attach retaining bolts.
Remove jack and lower engine.
Install motor mount through bolts.
Install starter.
Install exhaust pipes.
Install converter dust cover.
Lower vehicle.
Install fan shroud.
Install distributor cap.
Refill crankcase.
Install air cleaner.
Connect battery.
Start engine, check for leaks.
OIL PUMP (FIGURE 6A2-22)
Removal
1. Remove oil pan as previously outlined.
2. Remove pump to rear main bearing cap bolt and
remove pump and extension shaft.
Disassembly
1. Remove
the pump cover attaching bolts and the
pump cover. Mark gear teeth so they may be
reassembled with the same teeth indexing.
2. Remove the idler gear and the drive gear and
shaft from the pump body.
3. Remove the pressure regulator valve retaining
pin pressure regulator spring and valve.
4. If the pickup screen and pipe assembly need
replacing, mount the pump in a soft-jawed vise
and extract pipe from pump cover. Do not disturb
the pickup screen on the pipe. This is serviced as
an assembly.
Cleaning and lnspection
1. Wash all parts in cleaning solvent and dry with
compressed air.
2. Inspect the pump body and cover for cracks or
excessive wear.
3. Inspect pump gears for damage or excessive wear.
The pump gears and body are not serviced
separately. If the pump gears or body are
damaged or worn, replacement of the entire oil
pump assembly is necessary.
4. Check the drive gear shaft for looseness in the
pump body.
5. Inspect inside of pump cover for wear that would
permit oil to leak past the ends of the gears.
6. Inspect the pickup screen and pipe assembly for
damage to screen or pipe.
7. Check the pressure regulator valve for fit.
Assembly
1. If the pickup screen and pipe assembly was
removed, it should be replaced with a new part.
Loss of press fit condition could result in an air
leak and loss of oil pressure. Mount the pump in
a soft-jawed vise, apply sealer to outside diameter of
swaged end of pipe, and using Tool
J-8369 tap
the pipe in place with a plastic hammer.
NOTICE: Be careful of twisting, shearing or
collapsing pipe while installing in pump.
2. Install the pressure regulator valve and related
parts.
3. Install the drive gear and shaft in the pump body.
4. Install the idler gear in the pump body in the
original orientation.
5. Install cover gasket.
6. Install the pump cover and torque attaching
screws to specifications.
7. Turn drive shaft by hand to check for smooth
operation.
Installation
1. Assemble pump and extension shaft with retainer
to rear main bearing cap, aligning top end of
hexagon extension shaft with hexagon socket
lower end of distributor drive gear.
2. Install pump to rear bearing cap bolt and torque
to specifications.
3. Install oil pan as previously outlined.
ROD CAP AND
Figure 6A2-23 Measuring Connecting Rod Side
Clearance
CONNECTING ROD BEARINGS
Connecting rod bearings are of the precision
insert type and do not utilize shims for adjustment. DO
NOT FILE RODS OR ROD CAPS. If clearances are
found to be excessive, a new bearing will be required.
Service bearings are available in standard size and
.013mm and .026mm undersize for use with new and
used standard size crankshafts.
lnspection and Replacement
1. With oil pan and oil pump removed, remove the
connecting rod cap and bearing.
2. Inspect the bearing for evidence of wear or
damage. (Bearings showing the above should not
be reinstalled.)
3. Wipe both upper and lower bearing shells and
crankpin clean of oil.

2.8 LITER V-6 6A2-19
4. Measure the crankpin for out-of-round or taper
with a micrometer. If not within specifications,
replace or recondition the crankshaft. If within
specifications and a new bearing is to be installed,
measure the maximum diameter of the crankpin,
to determine new bearing size required.
5. If within specifications, measure new or used
bearing clearance with Plastigage or its
equivalent.
NOTICE: If a bearing is being fitted to an
out-of-round crankpin, be sure to fit to the
maximum diameter of the crankpin. If the bearing
is fitted to the minimum diameter and the
crankpin is out-of-round .025mm interference
between the bearing and
crankpin will result in a
rapid bearing failure.
a.
Place a piece of gaging plastic the full width
of the
crankpin as contacted by the bearing
(parallel to the crankshaft).
b. Install
the bearing in the connecting rod and
cap.
c. Install
the rod cap and evenly torque nuts
to specifications. Do not turn the crankshaft
with gaging plastic installed.
d. Remove
the rod cap and using the scale on
the gaging plastic envelope, measure the
gaging plastic width at the widest point.
6. If
the clearance exceeds specifications, select a
new, correct size, bearing and remeasure the
clearance.
If clearance cannot be brought to within
specifications, the
crankpin will have to be
ground undersize. If the
crankpin is already
at maximum undersize, replace crankshaft.
7. Coat the
bearing surface with oil, install the rod
cap and torque nuts to 50
N-m (37 lb. ft.).
8. When all connecting rod bearings have been
installed tap each rod lightly (parallel to the
crankpin) to make sure they have clearance.
9. Measure all connecting rod side clearances (see
specifications) between the rod cap and
crankshaft throw (Figure 6A2-23).
MAIN BEARINGS (FIGURE 6A2-24)
Main bearings are of the precision insert type and
do not utilize shims for adjustment. If clearances are
found to be excessive, a new bearing, both upper and
lower halves, will be required. Service bearings are
available in standard size and undersize.
Selective fitting of both rod and main bearing
inserts is necessary in production in order to obtain
close tolerances. For this reason you may find one half
of a standard insert with one half of a
.016mm
undersize insert which will decrease the clearance
.008mm from using a full standard bearing.
Inspection
In general, the lower half of the bearing (except
# 1 bearing) shows a greater wear and the most distress
from fatigue. If upon inspection, the lower half is
suitable for use, it can be assumed that the upper half
APPLY OIL TO ALL MAlN BEARINGS
E WITH ARROW ON CAP
FRONT OF ENGINE.
(1, 2 8, 3 ONLY).
Figure 6A2-24 Main Bearings
is also satisfactory. Of the lower half shows evidence
of wear or damage, both upper and lower halves should
be replaced. Never replace one half without replacing
the other half.
Checking Clearance
To obtain the most accurate results with
"Plastigage", (or its equivalent), a wax-like plastic
material which will compress evenly between the
bearing and journal surfaces without damaging either
surface, certain precautions should be observed.
If the engine is out of the vehicle and upside
down, the crankshaft will rest on the upper bearings
and the total clearance can be measured between the
lower bearing and journal. If the engine is to remain in
the vehicle, the crankshaft should be supported both
front and rear to remove the clearance from the upper
bearing. The toal clearance can then be measured
between the lower bearing and journal. When checking
# 1 main bearing, loosen accessory drive belts so as to
prevent tapered reading with plastic gage.
NOTICE: To assure the proper seating of the
crankshaft, all bearing cap bolts should be at their
specified torque. In addition, prior to checking the
bearing fit, the surface of the crankshaft journal
and bearing should be wiped clean of oil.
1. With the oil pan and oil pump removed, and
starting with the rear main bearing, remove
bearing cap and wipe oil from journal and bearing
cap.
2. Place a piece of gaging plastic the full width of the
bearing (parallel to the crankshaft) on the
journal. Do not rotate the crankshaft while the
gaging plastic is between the bearing and journal.
3. Install
the bearing cap and evenly torque the
retaining bolts to 95
N.m (70 lb. ft.). Bearing cap
MUST be torqued to specification in order to
assure proper reading. Variations in torque affect
the compression of the plastic gage.

4. Remove bearing cap. The flattened gaging plastic
will be found adhering to either the bearing shell
or journal.
5. On the edge of gaging plastic envelope, there is a
graduated scale which is correlated in
thousandths of a millimetre. Without removing
the gaging plastic, measure its compressed width
(at the widest point) with the graduations on the
gaging plastic envelope. Normally, main bearing
journals wear evenly and are not out-of-round.
However, if
a bearing is being fitted to an
out-of-round (.025mm max.), be sure to fit to the
maximum diameter of the journal: If the bearing
is fitted to the minimum diameter and the journal
is out-of-round
.025mm, interference between the
bearing and journal will result in rapid bearing
failure. If the flattened gaging plastic tapers
toward the middle or ends, there is a difference
in clearance indicating taper, low spot or other
irregularity of the bearing or journal. Be sure to
measure the journal with a micrometer if the
flattened gaging plastic indicates more than
,025mm difference.
6. If the bearing clearance is within specifications,
the bearing insert is satisfactory. If the clearance
is not within specifications, replace the insert.
Always replace both upper and lower inserts as
a unit.
7. A standard,
.016mm and .032mm undersize
bearing may produce the proper clearance. If not,
it will be necessary to regrind the crankshaft
journal for use with the next undersize bearing.
After selecting new bearing, recheck clearance.
8. Proceed to the next bearing. After all bearings
have been checked rotate the crankshaft to see
that there is no excessive drag.
9. Measure crankshaft end play (see specifications)
by forcing the crankshaft to the extreme front
position. Measure at the front end of the
#3 main
bearing with a feeler gage (Figure 6A2-25).
10. Install a new rear main bearing oil seal in the
cylinder block and main bearing cap.
Figure 6A2-25 Measuring Crankshaft End Play
Replacement
Main bearings may be replaced with or without
removing the crankshaft.
With Crankshaft Removal
1. Remove and inspect the crankshaft.
2. Remove the main bearings from the cylinder
block and main bearing caps.
3. Coat bearing surfaces of new, correct size, main
bearings with oil and install in the cylinder block
and main bearing caps.
4. Install the crankshaft.
Without Crankshaft Removal
With oil pan, oil pump and spark plugs removed,
remove cap on main bearing requiring
replacement and remove bearing from cap.
Install a main bearing removing and installing
tool in oil hole in crankshaft journal. If such a
tool is not available, a cotter pin may be bent as
required to do the job.
Rotate the crankshaft clockwise as viewed from
the front of engine. This will roll upper bearing
out of block.
Oil new selected size upper bearing and insert
plain (unnotched) end between crankshaft and
indented or notched side of block. Rotate the
bearing into place and remove tool from oil hole
in crankshaft journal. Inspect for burrs at oil hole,
remove if required.
Oil new lower bearing and install in bearing cap.
Install main bearing cap with arrows pointing
toward front of engine.
Torque all main bearing caps, EXCEPT THE
#3 MAIN CAP, to 95 N.m (70 lb. ft.). Torque
# 3 main bearing cap to 15 N m (1 1 lb. ft.) then
tap end of crankshaft, first rearward then forward
with a lead hammer. This will line up rear main
bearing and crankshaft thrust surfaces.
Retorque
all main bearing caps to 95 N.m (70 Ib. ft.).
1 /DUST LIP
Figure 6A2-26 Removing Seal

2.8 LITER V-6 6A2-21
SEAL BORE TO SEAL SURFACE
TO BE LUBRICATED
WlTH ENGINE OK BEFORE I ASSEMBLY
Figure
6A2-27 Seal and Tool J-34686
ALIGNMENT HOLE
DUST
LIP
I SCREWS I
Figure 6A2-28 Installing Seal
OIL SEAL - REAR MAIN
Repair
1. Remove transmission.
2. Remove flexplate.
3. Old
seal, insert a screwdriver or similar tool
through the dust lip at an angle as shown in
Figure
6A2-26. Pry seal out by moving handle of
tool towards the end of the crankshaft. Repeat as
required around the seal until seal is removed.
CARE MUST BE TAKEN NOT TO
DAMAGE THE CRANKSHAFT O.D.
SURFACE
WlTH THE PRY TOOL.
4. Check
the I.D. of bore for knicks or burrs and
correct as required. Inspect crankshaft for burrs
or knicks on surface which contacts seal. Repair
or replace crankshaft as required.
5. Install new seal using Tool J-34686, Figure
6A2-27.
6. Apply a
light coat of oil to I.D. of new seal and
install over mandril, slide the seal on the mandril
until the dust lip (back of seal) bottoms squarely
against collar of tool, Figure
6A2-28.
7. Align dowel pin of tool with dowel pin hole in
crankshaft and attach tool to crankshaft by hand
or torque attaching screw to 2-5 ft. lbs.
8. Turn
"T" handle of tool so that collar pushes seal
into the bore, turn handle until the collar is tight
against the case. This will insure that the seal is
seated properly.
9. Loosen the "T" handle of the tool until it comes
to a stop. This will insure that the collar will be
in the proper position for installing a new seal.
Remove attaching screws.
10. Check seal,
making sure seal is seated squarely in
the bore.
1
1. Install flywheel.
12. Install transmission.
13. Start
engine, check for leaks.
PISTONS, RINGS AND CONNECTING RODS
Removal
1. Remove cylinder heads.
2. Examine the cylinder bores above the ring tavel.
If bores are worn so that a shoulder or ridge exists
at the top of the cylinder, remove the ridges with
a ridge reamer to avoid damaging rings or
cracking ring lands in pistons during removal.
3. Use a silver pencil or quick drying paint to mark
the cylinder number on all pistons, connecting
rods and caps. Starting at the front end of the
crankcase the cylinders in the right bank are
numbered 1-3-5 and those in the left bank are
number 2-4-6.
4. Remove rod bearing
cap and bearing.
5. Install
guide hose over threads of rod bolts. This
is to prevent damage to bearing journal and rod
bolt threads.
6. Remove rod
and piston assembly through the top
of the cylinder bore.
Disassembly
1. Remove compression rings
and oil ring.
2. Install piston and connecting rod assembly on
fixture and support J-24086-20 and place in an
arbor press. Press pin out of connecting rod.
Inspection
1. Inspect cylinder walls for scoring, roughtness, or
ridges which indicate excessive wear. Check
cylinder bores for taper and out-of-round with an
accurate cylinder gage at top, middle and bottom
of bore, both parallel at right angles to the
cylinder bores at any point may be measured with
an inside micrometer or setting the cylinder gage
dial at
"0" and measuring across the gage
contact points with outside micrometer while the
gage is at same
"0" setting.
2. If a cylinder bore is moderately rough or slightly
scored but is not out-of-round or tapered, it is
usually possible to remedy the situation by
honing the bore to fit a standard service piston
since standard service pistons are high limit
production pistons. If cylinder bore is very rough
or deeply scored, however, it may be necessary to

rebore the cylinder to fit an oversize piston in
order to insure satisfactory results.
3. If cylinder bore is tapered 0. lmm or more or is
out-of-round
O.lmm or more, it is advisable to
rebore for the smallest possible oversize piston
and rings. Below these limits, the cylinder bore
can be trued up with honing.
4. Clean carbon from piston surfaces and under side
of piston heads. Clean carbon from ring grooves
with suitable tool and remove any gum or varnish
from piston skirts with suitable solvent.
5. Carefully examine pistons for
rough or scored
surfaces; cracks in skirt or head; cracked or
broken ring lands; chipped or uneven wearing
pistons would cause rings to seat improperly or
have excessive clearance in ring grooves.
Damaged or faulty pistons should be replaced.
The pistons are cam ground, which means that
the diameter at a right angle to the wrist pin is
greater than the diameter parallel to the wrist pin.
When a piston is checked for size, it must be done
at points 90" to the piston pin. The piston should
be checked (for fitting purposes) in a plane
through the piston pin centerline.
6. Inspect surfaces of wrist pins and check for wear
by measuring worn or unworn surfaces with
micrometers. Occasionally pins will be found
tight due to gum or varnish deposits. This may be
corrected by removing the deposit with a suitable
solvent. If piston bosses are worn out-of-round or
oversize, the piston and pin assembly must be
replaced. Oversize pins are not practical due to
the pin being a press fit in the connecting rod.
Piston pins must fit the piston with an easy finger
push at 70°F (21°C)
(.0065 to .0091mm
clearance).
7. Examine all piston rings for scores, chips or
cracks. Check compression rings for tension by
comparing with new rings. Check gap of
compression rings by placing rings in bore at
bottom of ring travel. Measure gap with feeler
gage. Gap should be between
0.25mm and 0.
50mm. If gaps are excessive (over 0.50mm) it
indicates the rings have worn considerably and
should be replaced. Bore wear should be checked
before rings are replaced,
. l25mm bore wear will
result in
.39mm increase in ring gap.
Assembly
There is a machined hole or a cast notch in the
top of all pistons to facilitate proper installation. The
piston assemblies should always be installed with the
hole toward the front of the engine (Figure
6A2-29).
1. Lubricate piston pin holes in piston and
connecting rod light with engine oil.
2. Position
conncecting rod in its respective piston.
Hold in place with piston pin guide and piston
pin. Place assembly on fixture and support
assembly
J-24086-20.
3. Press the piston pin into the piston and
connecting rod.
NOTCH TO
FRONT OF
ENGINE
Figure 6A2-29 Piston
NOTICE: After installer hub bottoms on support
assembly, do not exceed 5000 psi pressure, as this
could cause structural damage to the tool.
4. Remove piston and connecting rod assembly
from tool and check piston pin for freedom of
movement on piston.
0 Emj@NE Lm ENGINE IRON1 EWINI llWl 0
2 - 1 - 6 CYLINDER
"A" OIL
RING SACER CAP (Tang in Hola w Slot wihin Ad
"B" 011 RING MIL GArs
"C" 1ND COMPRESSION RIM GAB
"DM TOP COAarRESSlON RING GAP
Figure 6A2-30 Ring Gap Locations I
I
Installation I
Cylinder bores must be clean before piston
installation. This may be accomplished with a hot
water and detergent wash or with a light honing as
necessary. After cleaning, the bores should be swabbed
several times with light engine oil and a clean dry cloth.
1. Lubricate connecting rod bearings and install in
rods and rod caps.
2. Lightly coat pistons, rings and cylinder walls
with light engine oil.
3. With bearing caps removed, install guide hose
over connecting rod bolts. These guide hoses
protect the
crankpin journal from damage during
installation of connecting rod and piston
assembly.

2.8 LITER V-6 8A2-23
4. Make sure the gap in the oil ring rails are in "up"
position toward center of engine and the gaps of
the compression rings are positioned as shown in
Figure
6A2-30.
5. Install each connecting rod and piston assembly
in its respective bore. Install with connecting rod
bearing tang slots on side opposite camshaft. Use
Tool J-8037 or J-8910 to compress the rings.
Guide the connecting rod into place on the
crankshaft journal.
Use a hammer handle and light blows to install
the piston into the bore. Hold the ring
compressor firmly against the cylinder block
until all piston rings have entered the cylinder
bore.
6. Install the bearing caps and torque nuts to
specifications. If bearing replacement is required
refer to "Connecting Rod Bearings".
Be sure to install new pistons in the same
cylinders for which they were fitted, and used
pistons in the same cylinder from which they
were removed. Each connecting rod and bearing
cap should be marked, beginning at the front of
the engine.
On V-6 engines, 1,3 and 5 are in the right bank
and 2,
4 and 6 are in the left bank. The numbers
on the connecting rod and bearing cap must be on
the same side when installed in the cylinder bore.
If a connecting rod is ever transposed from one
block or cylinder to another, new bearings should
be fitted and the connecting rod should be
numbered to correspond with the new cylinder
number.
NOTE. All dlrnenslons are In rn~ll~rnetres.
Figure 6A2-3 1 Service Pistons
HONING OR REBORING CYLINDERS (FIGURE
6A2-32)
If one or more cylinder bores are rough, scored
or worn beyond limits, it will be necessary to smooth
or true up such bores to fit new pistons.
If relatively few bores require correction, it will
not be necessary to
rebore all cylinders to the same
oversize in order to maintain engine balance. All
HONED SURFACE
1.
Cross Hatch Angle 20' - 32'
2.
Uniformly Cut in Both Directions
3. Clean Cut Not Sharp Free of Torn and
Folded Metal
4. Micro Ave. 10-20 Micro In. (0.254.30 micrometers) Range 10-1 5 micro in.
(0.25-0.38 micrometers)
5. Cross Hatch Ave.
.0004"-.0006" Wide
Range ,0002"-.0009"
6. Cross Hatch Ave. ,0001 5"-.00025" Deep Ranw ,0081 "-.0003"
7. Plateau to be 1/2 to 2/3 of Surface
8. Free of Burnish or Glaze
I 9. Free of Imbedded Particles I
I I Figure 6A2-32 Honing Specifications
oversize service pistons (Figure 6A2-3 1) are held to the
same weights as standard size pistons.
No attempt should be made to cut down oversize
pistons to fit cylinder bores as this will destroy the
surface treatment and affect the weight. The smallest
possible oversize service pistons should be used and the
cylinder bores should be honed to size for proper
clearances.
Before the honing or
reboring operation is
started, measure all new pistons with micrometer
contacting at points exactly 90 degrees from piston pin
centerline then select the smallest piston for the first
fitting. The slight variation usually found
beween
pistons in a set may provide for correction in case the
first piston is fitted too free.
If wear at top of cylinder does not exceed 0.10
mm on the diameter or exceed
0.lOmm out-of-round,
honing is recommended for truing the bore. If wear or
out-of-round exceeds these limits, the bore should be
trued up with a boring bar of the fly cutter type, then
finish honed.
When
reboring cylinders, all crankshaft bearing
caps must be in place and tightened to proper torque
to avoid distortion of bores in final assembly. Always
be sure the crankshaft is out of the way of the boring
cutter when boring each cylinder. When taking the
final cut with boring bar, leave
,025mm on the
diameter for finish honing to give the required
clearance specified.
When honing cylinders, use clean sharps tones of
proper grade for the amount of metal to be removed,
in accordance with instructions of the hone
manufacturer. Dull or dirty stones cut unevenly and
generate excessive heat. When using coarse or medium
grade stones use care to leave sufficient metal so that
all stone marks may be removed with the fine stones
used for finishing to provide proper clearance.
It is of the greatest importance that refinished
cylinder bores are trued up to have not over
.02mm