Vibrations Originating At Engine; Low Oil Pressure; High Oil Pressure - Fiat 850 Sedan 1968 Shop Manual

ENGINE: TROUBLES AND CORRECTIONS
Vibrations Originating at Engine.
21
POSSIBLE CAUSES
t) Misfiring.
2) Defective carburetion.
3) Crankshaft out of balance.
4) Connecting rods and pistons of different weights.
5) Tappets mis.djusled.
6) Engine mountings worn or too tight.
Low Oil Pressure.
POSSIBLE CAUSES
1) Incorrect grade of oil.
2) Defective or stuck oil prenure relief valve.
3} Worn or damaged 011 pump gea,•.
4) Excessive clearance between main and conned-
Ing rod bearings and journals.
5)
Inaccurate low oil pressure Indicator.
6)
Damaged seal ring at flywheel end of crankshaft.
High Oil Pressure.
POSSIBLE CAUSES
1)
Wrong grade engine
011
(too heavy).
2) Defective
011
pressure relief valve.
3) Restricted 011 passagu.
REMEDIES
1) Check and overhaul Ignition as outlined In covering chapter.
2) Check and blow clean carburetor jets and
panage.
and
adjust Idling .peed.
3) Remove and balance crankshaft as outlined under« Crank·
ahaft ».
4) Dismantle connecting rod· piston assemblies and equalize
weights as outlined In covering chapter.
5) Adjust to specified tappet clearance.
6) Replace mountings.
REMEDIES
1) Change to correct 011 quality as reported on lubrication
chart (page
7).
2)
Overhaul or replace valve.
3)
Rebuild oil pump
as
outlined In covering chapter.
4)
Remove and inspect crankshaft;
if
necessary, grind crank-
shaft and replace bearings.
5)
In sped and replace damaged parts.
6)
Replace seal ring as directed under «
Oil
Seals
It.
REMEDIES
1)
Change to correct oil quality as reported on lubrication
chart (page 7).
2)
Overhaul or replace valve.
3) Flush engine lubrication circuit thoroughly.