Fiat 850 Sedan 1968 Install guide

SECTION INDEX
GENERAL
ENGINE
Section
Page
1
3
2
SEDAN COUPE
ROADSTER· FAMILY
IDROCONVERT
9
'85
AIR CONDITIONING
WINDSHIELD WASHER
TIGHTENING REFERENCE
BRAKES
WHEELS AND TIRES
STEERING 17
============~ 157
I,Q
9
LUBRICATION
~
COOLING
FUEL SYSTEM
CLUTCH - TRANSMISSION
4
DIFFERENTIAL
FRONT SUSPENSION
,~
AND WHEELS
REAR
SUSPENSION
",
AND
WHEELS
.§
SHOCK ABSORBERS
MANUAL
MODEL
SHOP
BODY .
ELECTRICAL 110
~========~ 195
lu
FIAT" SERVICE DEPARTMENT" TURIN
MAINTENANCE
1~
TOOL EQUIPMENT
COUPE· ROADSTER
1~
FAMILY.IDROCONVERT

IMPORTANT
All the dimensions in metric units shown
in this publication are the official ones.
Dimensions are also given in British and
American units for prompt reference, and
they have been calculated to a degree of ap-
proximation according to the need for accu-
racy in individual measurements.

Section 1
GENERAL
INfORMATION
MAIN SPECIFICATIONS
PERFORMANCES
CAPACITIES
UNIT IDENTIFICATION DATA
SPARE PARTS
CAR KEYS
Page
:11
7
8
8
8

4 FIAT·850 PASSENGER CARS
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GENERAL: MAIN SPECIFICATIONS 5
GENERAL INFORMATION
Specifications, features and service procedures outlined in this publication are intended to
apply to the Sedan Version.
Differing parts, data and procedures of Coupe, Roadster, Station Wagon and Idroconvert
Versions, as referred to the Sedan, are described in Section 13.
Wear limit figures are given just for the serviceman's information and should not be taken as
absolute values.
MAIN SPECIFICATIONS
Identification Data.
Chassis type .
Engine type !•
Standard. version
• Super. version
lOOG
lOOG.OOO
lOOG.OO2
3rd, synchromeshed
4th, •
Reverse .
Hypoid final drive gear ratio
Steering.
1.409 to I
0.963 to I
3.615 to I
4.625 to I(8/37)
13 to I(2/26)
31' 6" (9.60 m)
Worm-and-seetor.
Gear ratio ..
Turning circle . .
Front Suspension.
Rear Suspension.
Independent wheel.
Coil springs, control arms, hydraulic shock absor-
bers, sway bar.
Rear wheel toe-in (full load) .039" to .118" (I to 3rom).
Independent wheel.
Transversal semi-elliptic spring, upper control arms,
hydraulic shock absorbers, sway bar.
Toe-in (full load). 079" to .157" (2 to 4rom)
Camber (full load):
- angle . 20 10'± IS'
- amount, at wheel rim
.472" to .512" (12 to 13 rom)
Caster. . . . . . . . . . . . gO±lo
40
42
.5,300 r .p.m.
.5,300 r.p.m.
8.0 to I
8.8 to I
rear
4-stroke, gasoline
4, in-line
2.559" (65 rom)
2.500" (63.5 rom)
.51.44 cu.in (843 em')
Engine.
Location .
Cycle ..
No. of cylinders
Bore .
Stroke . . . . .
Piston displacement .
Compression ratio:
-(I Standard l) version
-(I Super» version. .
Maximum horsepower (SAE):
- • Standard» version
- 4l Super t version. .
f 4l Standard. version . .
at
}. Super. version . . .
Maximum horsepower (DIN):
- • Standard. version 34
-•
Super. version. .37
I.
Standard. version .4,800 r .p.m.
at •
Super. version . . 5,000 r .p.m.
Taxable horsepower Otaly) II
Cooling ....... permanent circuit mixture
Clutch.
Brakes.
Single plate. dry.
Diaphragm-type pressure spring.
Transmission· Differential.
Drum diameter . . . . .
Master cylinder bore . .
Bore of wheel cylinders:
- front
-rear .
7.283" (185 rom)
3/4"
7/6"
3/4".
Rear drive.
Gear ratios:
1st, synchromeshed
2nd, t3.636 to I
2.055 to I
Wheels and Tires.
Disc wheels, size
Tire size .... 4.00-12" 5.50-12"

6 FIAT· 850 PASSENGER CARS
Tire pressure:
four people and luggage
five people and luggage
Front Rear
~ kg/em' _"_'_1 kg/em'
15.6 1.1 25.6 1.6
17.1 1.2 28.4 2
Payload, maximum , . . . .. 852 lbs (400 kg)
Gross weight, full load . , . ,2,359lbs(I,070kg)
Distribution of gross weight on axles:
front 904lbs (410 kg)
-
rear .. ........ 1,455 lbs (660 kg)
Electric System.
Performances.
Weights.
31%
17%
10%
6%
road in
(30 kmfh)
(55 km/h)
(85 kmfh)
75
mph (120 km/h)
78
mph (125 km/h)
Gradeability, under full load, with level
good condition and run-in engine:
first gear
second gear
third gear .
fourth gear .
Speed, maximum, under full load, with level road
in
good condition and run-in engine:
first gear 19 mph
second gear . . 34 mph
third gear ... 53 mph
fourth gear. abt:
-«Standard ~ version
- ( Super l) version. .
1,477 lbs (670 kg)
4-5 people
110 lbs (50 kg) luggage plus
Voltage .. ............ 12
Battery (ZQ-hr discharge rate), capacity 36 Amp. hrs
Generator FlAT type D90/12/16/3 C5 .230 Watts
Generator regulator FIAT type GN 2/12/16.
Starting
motor FIAT type E76-0,5/12 S Var. 9.
Curb weight (with water, oil,
fuel,
spare wheel, tool kit and
accessories)
Accomodation
984
661
2027 887
1146
3575 1425
~
I
1Il
~
=
~
~
~
=
~
•
9•
I
Fig. 2 - Leading dimensions of car (metric).
Overall height applies to an unloaded vehicle.

GENERAL: CAPACITIES
7
CAPACITIES
Fuel tank ..6.60
gals
7.93 gals 30
Radiator I engine and heating
system.
1.65 1.98 7.S
pints pints
Sump and filter (.) .5.72 6.87 3.25 2.90
Transmission and differential 3.70
4.44 2.10 1.90
Steering gear
0.211 0.254 0.12 0.11
Braking system .0.457 0.549 0.26 0.26
Front shock absorbers (each) 0.299 0.359 0.170 0.155
Rear shock absorbers (each)
0.264 0.3/7 0.150 0.135
Windshield washer reservoir
(') (') (')
UNIT
QUANTITY
I Imp. units U.S. units __ It __ ! __ k--,g::.-
FILL-IN
B3 octane gasoline (R. M.),
t: Standard It version
92 octane gasoline, min.
(R. M.), ,Super. version
Mixture of water and FIAT
Paraflu 11 fluid (50% by
volume) (')
FIAT oil (3)
FIAT W 9O/M oil (SAE 90 EP)
PIAT special t: blue label It fluid
FIAT S.A./. fluid
Water and FIAT D.P./I fluid
mixture (concentrated so-
I lution).
(-) The total capaClty of sump, pipings and crankshaft is 6.48 G.B. pts -7.80 U.S. pts (3.3 kg). The quantity shown in the table applies
to routine oil changes, which should be made every 6,000 miles (10,000 km) or siJ: months. Every 300 miles (500 kin), check oil level.
(I) The coolant has non--oxidizing, non-corrosive. non-foamy, non-scaling properties and will nOI freeze up 10 -31
eF
(-35
0C).
(I) Pure water .66 G.B. qts -.79 U.S. qts (0.75 kilos) plus .6 oz (17 gr) solution in summer and 1.20 oz (34 gr) solution in winter.
(') Use the following grcades of oil: .
TEMPERATURE
flAT UNlGRADE On. IFIAT MULTIGRADE On.
(supplement 11evel oils which fill MS sequence requirements)
Below +5
0F
(-IS° C), minimum VS 10 W(SAE 10 W)
20 W40
10 W30
VS 30 (SAE 30) II
VS 40 (SAE 40) \
VS 20 W(SAE 20 W)
Between 320F (O°C) and +5°F (ISoC), minimum
Above 32° FI Below 95°F (35°C). maximum
(OOC), minimum Above 950F (350C), maximum
WARNING· These FIAT oils are detergent, and oils of different grade or malce should not be used for toppmg up. If detergent
oils are being used for the first time on an engine which is not new, the system should be carefully drained and flushed.
Fig. 3.
Power plant (engine-clutch.
transmission and differential
aSlY)·

8
FIAT - 850 PASSENGER CARS
UNIT IDENTIFICATION DATA
Fig ....
location of unit iden-
tification
numbers.
A. Unit identification plate. -B. Chassis type (100G) and serial number .• C. EngIne
type (1006.000
for the «Standard)) version and 1006.002 for the « Super» version) and
serial number.
NOTE -Starting from car with parts serial
number 667161, plate "A" and stamping
"B" are located on partition wall between engine compartment and fuel tank.
SPARE PARTS
CAR KEYS
When placing orders for spare parts, state:
- car Model;
- engine serial number or serial number for
spare parts, according to whether parts for engine
or running gear are requested;
- nwnber of spare part or parts on order, as
given in spare parts catalogue.
Each new car is equipped with two sets of keys
to suit:
- ignition and starting switch;
- door locks.
A code number is stamped on key bow.
To have car key duplications made through the
cutting machine Ap. 5013. just specify the code
number of the key on order and relevant description.

Section 2
ENGINE
MAIN SPECIFICATIONS
TROUBLES AND CORRECTIONS
REMOVAL AND INSTALLATION
DISASSEMBLY
Page
11
13
23
24
2
ASSEMBLY 26
CYLINDER BLOCK AND CRANKCASE 29
PISTONS· CONNECTING RODS 35
CRANKSHAFT AND MAIN BEARINGS 45
CYLINDER HEAD· VALVES - VALVE
GUIDES· SPRINGS AND ROCKERS 53
VALVE MECHANISM 63
TIGHTENING REFERENCE 68
BENCH TEST 69

10
FIAT·850 PASSENGER CARS
Fig. 6 - Side sectional view of engine across cylinders.

ENGINE: MAIN SPECIFICATIONS
ENGINE
MAIN SPECIFICATIONS .
TROUBLE DIAGNOSIS AND CORRECTIONS
REMOVAL AND INSTALLATION
DISASSEMBLY
ASSEMBLY ..
11
page 11
» 13
) 23
»24
» 26
M A I N
SPECIFICATIONS
Engine. «Standard
))
Version «Super» Version
Type
··100G.000 100G.002
Cycle
and strokes
·Otto, four-stroke
No. of cylinders, in line.
···· · four
Bore · · · · 2.559" (65 mm)
Stroke ·2.500" (63.5 mm)
Displacement ·51.44
cu.in (843 c.c.)
Compression ratio
8.0 to I 8.8 to I
Maximum horsepower
(DIN) · · · 34 37
at ··4,800
r.p.m.
5,000 I.p.rn.
Maximum horsepower
(SAE) · · · 40
42
at .· · ·S,300
r.p.m.
5,300 r.p.m.
Maximum torque
(DIN) ··· · 39.8
it.lbs (5S0 kgcm) 40.5 it.lbs (560 kgcm.
at
3,200 r.p.m.
3,400 r.p.m.
Maximum torque (SAE) ·42.7
it.lbs (590 kgcm)
44.1 ft.lbs (610 kgcm)
at
···3,400
r.p.m.
3,600 r .p.m.
Taxable horsepower (Italy) · ·
II
Crankshaft.
No. of main bearings · ·
three
Bearings ·
steel backed babbitt
Thrust ring halves ·two,
intermediate bearing top
Rotation · ·
counterclockwise
Connecting Rods.
Bearings ··
steel backed babbitt
Pistons.
Type
·· ·
steel-belted, slipper design
First ring
· ·
compression
Second ring .· · ··oil
Third ring
· · · · · .oil radial slotted
Boss
bore . . · · ..079" (2 mm)
offset
Pin ,···press fitted in small end
(continued)

12 FIAT· 850 PASSENGER CARS
Main Specifications (continued).
chain
overhead
in crankcase
100G.000 IIOOG.002
--------1
Valve Gear.
Drive
Valves
Camshaft
Air cleaner
Recirculation device of blow-by gases and oil vapours
Fuel System.
Pump type .•
Driven by
Carburetor. single
Weber or Holley Europea, type
or
Salex, type
mechanical, diaphragm
camshaft
30 ICF 30 ICF I
30PW4 30PW4
pleated paper cartdridge
Lubrication.
Pump type
Filter type
Pressure relief valve.
Metered pressure
gear
centrifugal
42.7 to 56.9 psi (3 to 4 kg/em')
Cooling.
Type
Pump type
Radiator type
Fan and pump drive
Thermostat
permanent mixture
centrifugal
fin and tube
belt
engine outlet duct
batteryIcamshaft
driven distributor
I - 3 - 4 - 2
13'
.0165" to .0189" (0.42 to 0.48 rom)
Marelli
CW 240 L - Champion N 4
.024" to .028" (0.6 to 0.7 rom)
14 x1,25
Ignition.
Type .· ·
Firing order
·
Static advance
Centrifugal automatic advance (to
engine)
Vacuum. advance (to engine)
·
Breaker point gap
·
Spark plugs
··
-
gap
·.··
-diameter and pitch, metric ··.·
II'
29'
10'
25'
Starting.
Type ..· ·
Pinion drive
..·
Control · ·
motor drive
solenoid
key
Engine Mountings.
Type
resilient, rubber blocks at three points

ENGINE: TROUBLES AND CORRECTIONS
ENGINE TROUBLE DIAGNOSIS AND CORRECTIONS
Engine Will Not Start.
13
POSSIBLE CAUSES
1) Weak battery.
2) Corroded or loose ba"ery terminal connections.
3) Defective starting motor.
4) Damaged ignition switch contacts.
5) Weak coil.
&) loose or broken ignition cabin from coil to
distributor and from distributor to spark plugs.
7) Cracked distributor cap.
8) Moisture or dirt deposits on distributor cap con-
tact points or current leads.
9) Distributor breaker contact point a dirty, oxidized
or blaekenedi pitted points or excessive point gap.
10) Distributor rotor cracked, .howing Ilgnl of burn-
ing or wet.
11) Center spring. mounted distributor cap contact
worn or broken or with distorted pressure spring.
12) Shorted condenser or with poor Inlulalion.
13) Fouled spark plugs or excessive spark plug gap.
t4) Improper timing (ignition).
t5) Incorrect fuel level In carburetor bowl.
18) Dirt or water in fuel line or carburetor.
17) Defective fuel pump.
REMEDIES
t) Cheek and recharge battery as recommended under
« Battery».
2) Clean, examine and tighten clamps to battery terminals.
Replace cables and clamps If they are too much corroded.
3) Locate failure and correct as recommended under III Starting
Motor •.
4) Locate failure and correct as recommended under« Starting
and Ignition Switch ••
5) Check coil and replace by a new one.
6) Examine and reset circuit or replace faulty cables.
7) Replace cap.
8) Wipe and clean leads and points.
9) Clean contacts and adjust point gap as recommended
under «Ignition Distributor •.
to) Clean or replace rotor, if necessary.
11) Replace contact and contact spring.
12) Bench test condenser and replace it, if defective.
t3) Clean spark plugs and set gap as recommended under
« Spark Plugs •.
14) Check and set timing as recommended under «Ignition
Timing ».
15) Check fuel level In bowl and adjust it, if necessary, as
recommended under «Carburetor ».
16) Remove and thoroughly clean carburetor; if trouble recurs,
flush and blow fuel tank and lines.
17) Remove and rebuild fuel pump.

14
Engine Stalls.
POSSIBLE CAUSES
1) Idling speed too low.
2) Fuel mixture too lean or too rich.
3) Needle valve in carburetor stuck.
FIAT - 850 PASSENGER CARS
REMEDIES
1) Increase throttle opening slightly and adjust mixture rating
as recommended under ( Carburetor».
2) Adjust mixture rating as recommended under« Carburetor ».
3) Rebuild as recommended under« Carburetor)).
4) Incorrect fuel level In carburetor bowl.
5) Carburetor flooding.
6) Dirt or water in fuel line or carburetor.
1) Loose or corroded battery terminals.
8) Loose ignition cables from coil to distributor and
from distributor to spark plugs.
9) Loose ignition switch connections.
10) Spark plugs dirty, damp or gaps set too wide.
11) Distributor breaker contact points dirty, oxidized
or pitted or point gap set too wide.
12) Distributor rotor contact worn.
13) Inoperative automatic centrifugal advance.
14) Defective coil or condenser.
15) Exhaust system restricted.
16) Incorrect valve tappet clearance, as adjusting
screws have become loose from poor tightening.
17) Engine overheating.
4) Check and adjust fuel level.
5) Proceed as recommended under {( Carburetor)).
6) Remove and throughly dean carburetor; If trouble recurs,
flush and blow fuel tank and lines.
7) Clean terminals and tighten nuts as recommended under
« Battery)). Replace cables and terminal clamps If they
are too much worn.
8) Examine and reset circuit.
9) Examine and reset circuit.
10) Clean spark plugs and set gap as recommended under
{( Spark Plugs »).
tt) Clean contacts and adjust point gap as recommended
under « Ignition Distributor ».
12)
Replace distributor rotor.
13) Rebuild ignition distributor as recommended In covering
chapter.
14) Inspect and replace both of them, if necessary.
15) Thoroughly clean exhaust silencer, exhaust piping and
manifold.
16) Adjust tappet clearance as recommended under (( Valve
Mechanism n.
17) Check water level in expansion tank, fan and water pump
drive belt tension, water pump and thermostat operation,
and overhaul as required.

ENGINE: TROUBLES AND CORRECTIONS
Engine Has No Power.
15
POSSIBLE CAUSES
1) Inconect ignition timing.
2) Weak coil or condens.r.
3) Reduced accelerator pedal t,avel.
•) Distributor rotor contaet worn.
5) Defective centrifugal or vacuum advance (dis.
tributor).
6) Excessive play in distributor shaH.
7) Weak spring In breaker contact point.
8) Distributor cam worn.
9) Insufficient distributor point dwell.
10) Spark plugs dirty, damp or gap set too wide.
11) Low grade fuel.
12) Weak valve springs.
13) Valves sticking when hot, burned or twisted.
14) Incorrect valve tappet clearance.
15) Worn camshaft lobes.
16) Valve timing inCOfrect.
11) Poor compression.
18) Defective fuel pump.
19) Too rich or lean fuel mixture.
29) Incorrect fuel level In carburetor bowl.
21) Engine overheating.
REMEDIES
1) Inspect and se1 Ignition timing as recommended under
«Ignition Timing ».
2) Bench test coli and condenser as recommended under
«Ignition Coil» and «Ignition Distributor ». Replace both
pans, if necessary.
3) Locate failure and correct It .
4) Replace distributor rotor.
5) Rebuild ignition distributor and vacuum advance, as
recommended in covering chapters.
6) Rebuild distributor and replace damaged pans.
7) Replace distributor breaker arm, spring and point assembly.
8) Overhaul distributor and replace cam body.
9) Adjust point dwell angle as recommended under u Ignition
Distributor ».
10) Clean spark plugs and set gap as recommended under
«Spark Plugs II.
11) Use fuel with recommended octane number.
12) Take down cylinder head and check spring pressure by
comparing figures with those tabulated under «Valve
Springs ».
13) Overhaul valves and valve guides as recommended under
«Cylinder Head »; replace as required.
14) Adjust tappet clearance as recommended on page 67.
15)
Check valve timing and compare data with those in valve
timing diagram, as shown under II Valve Mechanism »;
replace camshaft, if necessary.
16) Time valves as recommended In covering chapter.
17) Check compression (106.7 to 113.1 psi. 1.5 to I kg/cm
l,
Standard Version; 120.9 to 135.1 psi. 1.5 to 9.5 kg/cm
l,
Super Version) using a pressure gauge; If pressure Is too
low, locate failure and rebuild engine.
18) Rebuild fuel pump and replace worn pans.
19) Check calibration of carburetor jets as outlined In cover·
Ing chapter; proceed as required.
20) Check fuel level In bowl and adjust as recommended
under «Carburetor ••
21) Check water level In expansion tank, fan and water pump
drive belt tension, water pump and thermostat operation
and overhaul .. required.

16 FIAT· 850 PASSENGER CARS
Engine « Lopes» or Misses at Idle.
POSSIBLE CAUSES
1) Incorrect carburetor idle adjustment.
2) Dirty or plugged lets or passages In carburetor.
3) Dirt or water In fuel line or carburetor.
4) Carburetor flooding.
5) Leaking gaskets or spacer between carburetor and
Intake manifold.
6) Leaking gaskets between Intake manifold and
cylinder head.
7) Blown cylinder head gasket.
8) Incorrect valve tappet clearance.
9) Stiffened, burned or warped valves.
to) WOrrJ camshaft lobes.
11) Worn timing chain.
12) Uneven compression rates.
13) Engine overheating.
14) Incorrect Ignition timing.
15) leaks In Ignition wiring.
16) Defective mechanical or vacuum advance
mechanisms.
17) Excessive play In distributor shaft.
18) Distributor cam worn.
19) Spark plugs damp, dirt or the gaps set too wide.
REMEDIES
1) Adjust idle as recommended under « Carburetor II.
2) Remove carburetor and clean lets and passages.
3) Remove and thoroughly clean carburetor; If trouble recurs,
flush
and blow fuel tank and lines.
4) Remove and rebuild carburetor, paying particular attention
to fuel level In bowl.
5) Check carburetor mounting flange for distortion, replace
gaskets and tighten nuts properly.
6) Check intake manifold flanges for distortion and gaskets
for damage and proceed as required.
7) Check mating surfaces for level, replace gasket and tighten
screws at specified torque.
8) Adjust clearance as recommended under «Valve Mech-
anism )1.
9) Rebuild cylinder head.
10) Check valve timing and compare data with those In valve
timing diagram, as shown under «Valve Mechanism »;
replace camshaft, if neceuary.
11) Replace chain.
12) Using preuure gauge, check compression In each cylinder
and rebuild engine, if required.
13) Check coolant level in expansion tank, fan and water
pump drive belt tension, water pump and thermostat
operation and overhaul as required.
14) Set ignition timing.
15) Locate leaks and correct as neceuary.
16) Rebuild ignition distributor and vacuum advance as
recommended under «Ignition Distributor ».
17) Rebuild Ignition distributor and replace worn parts.
18) Rebuild Ignition distributor and replace cam body.
19) Clean spark plugs and adjust gap as recommended under
«Spark Plugs II.

ENGINE: TROUBLES AND CORRECTIONS
Engine Misses at High Speed.
17
POSSIBLE CAUSES
1) Dirty jets in carburetor, especially the main jets
and emulsion well •.
2) Dirt or water In fuel line or carburetor.
3) Incorrect Ignition timing.
4) Weak coil or condenser.
5) Distributor breaker points dirty or Incorrectly
spaced.
6) Distributor rotor contact worn.
7) Loose ignition wiring.
8) Excessive play In distributor shaft.
9) Spark plugs dirty, damp or the gaps set too wide.
10) Weak distributor point contact.
11) Insufficient spring tension on contact breaker
arm.
12) Distributor cam lobe worn.
13) Oeton.tion or preignition.
,.) Weak valve spring ••
15) Worn camshaft lobe •.
16) Badly worn diaphragm In fuel pump.
17) Engine overheating.
REMEDIES
1) Remove jets and blow clean.
2) Remove and thoroughly clean carburetor; if trouble recurs,
flush and blow fuel tank and lines.
3) Set Ignition timing as recommended in covering chapter.
4) Bench test call and condenser and replace by new ones,
if necessary.
5) Clean and adjust points.
6) Replace distributor rotor.
7) Check wiring cables and reset contacts.
8) Rebuild ignition distributor and replace worn parts.
9) Clean spark plugs and adjust gap as recommended under
«Spark Plugs ».
10) Smooth distributor points and adjust gap.
11) Replace breaker arm auembly.
12) Rebuild Ignition distributor and replace cam body.
13) Check spark advance and set Ignition timing, where nec-
enary. Make sure that spark plugs are of the Factory
recommended grade and In serviceable con dillon.
If piston and combustion chambers are carboned up, use
higher grade fuel.
14) Remove cylinder head and replace springs.
15) Check valve timing and compare data with those In valve
timing diagram as shown under c( Valve Mechanism IIi re-
place camshaft, If necessary.
16) Remove fuel pump and replace diaphragm as recom-
mended under «Fuel Pump D.
17) Check coolant level In expansion tank, tan and water
pump drive belt ten.lon, water pump and thermostat oper-
ation and overhaul as required.

18 FIAT· 850 PASSENGER CARS
Engine Misses While Idling.
POSSIBLE CAUSES
1) Spark plugs dirty, damp or the gaps set too wide.
2) Broken or loose ignition wires.
3) Burned or piUed breaker contact points, or set
with insufficient gap.
4) Coil or condenser defective.
5) Distributor cap cracked.
6) Distributor rotor contact worn.
7) Excessive play In distributor shaft or shaft cam
worn.
8) Burned, warped or pitted valve •.
9) Incorrect valve tappet clearance.
10) Incorrect <:arburetor idle adjustment.
11) Incorrect fuel level in carburetor.
12) Poor compression.
Crankshaft Knocks.
REMEDIES
1) Clean spark plugs and adjust gap as recommended under
It Spark Plugs ».
2) Check wiring cables for secure fastening to terminals and
spark plug inserts.
3) Overhaul and adjust contact points as recommended under
«Ignition Distributor ».
4) Bench test coli and condenser and replace them, if
required.
5) Replace cap.
6) Replace distributor rotor.
7) Rebuild ignition distributor and replace worn parts.
8) Overhaul cylinder head and replace valves. Proceed u
recommended under « Cylinder Head If.
9) AdJust clearance as recommended under «Valve Mech-
anism ».
10) Adjust idle speed as recommended under «Carburetor If.
11) Check and adjust float level as recommended under « Car-
buretor ».
12) Check compression using a pressure gauge: If pressure
is too low, locate causes and remove them.
These knocks are usually detected as metallic, heavy and dull knocks which increase in frequency
with the engine speed. Excessive crankshaft end play (shoulder play) causes a sharper. drier noise which
occurs at irregular intervals.
POSSIBLE CAUSES
t) Excessive clearance between main bearings and
journals.
2) Excessive end play.
REMEDIES
1) Remove crankshaft, check Journals and bearing condition;
grind crankshaft and replace bearings as outlined under
« Crankshaft».
2) Cheek end play and ule oversize thrust rings, If necessary.
(CI:ltltlnued)

Cran kshaft Knocks (con!jnu~).
ENGINE: TROUBLES AND CORRECTIONS
19
POSSIBLE CAUSES
3) Out-of-round or tapered main bearing journals.
4) Crankshaft out of balance.
5) Poor oil delivery.
6) Low oil pressure.
7) Loose flywheel on crankshaft.
8) Improper or diluted oil.
Noisy Connecting Rods.
REMEDIES
3) Remove crankshaft, check journal diameter: next grind
crankshaft and replace bearings as outlined under (( Crank-
shaft )l.
4) Remove crankshaft and check balance with flywheel and
clutch installed as outline:l under «Crankshaft».
5) Check and rebuild oil pump as outlined in relevant chapter.
See that the 011 lines are not plugged or restricted.
6) Take down and disassemble engine, then:
a) Check the 011 pressure relief valve for binding and proceed
as required.
b) Check the seal rings in crankshaft rear bearing oil shield
disk for wear and replace them, if worn.
7) Tighten flywheel screws with specified torque.
8) Replace oil by correct grade as tabulated on page 7.
COlUlecting rod noises are usually more intense than main bearing knocks. The noise is more evident,
as a rule, with the engine idling and in neutral and becomes louder when engine speed is increas ed.
Connecting rod noise can be best located by short circuiting one spark plug at a time.
POSSIBLE CAUSES
1) Excessive clearance between con rod bearings
and Journals.
REMEDIES
1) Take down rod
and journals.
crankshaft.
bearings and check wear of rod bearings
If necessary, replace bearings and grind
2) Out-of-round or tapered connecting rod journals.
3) Poor oil delivery.
4) Low 011 pressure.
5) Misaligned connecting rods.
6) Improper or diluted 011.
2) Remove crankshaft, grind connecting rod journals and
replace bearings.
3) Check and rebuild 011 pump as outlined in relevant chapter.
See that 011 lines are not plugged or restricted.
4) Take down and disassemble engine, then:
a) Check the 011 pressure relief valve for binding and pro-
ceed as required.
b) Check the seal rings in crankshaft rear bearing 011 shield
disk for wear and replace them, If worn.
5) Dismantle connecting rod~piston assemblies and align con-
necting rods as outlined In covering chapter.
6) Replace 011 by correct grade as tabulated on page 7.