4.
5.
Remove bearing cap. The flattened gauging
plastic will be found adhering to either the bearing
cap or journal.
8. Proceed to the next bearing. After all bearings
have been checked, rotate the crankshaft to see
that there is no excessive drag. When checking
No. 1 main bearing, loosen accessory drive belts
so as to prevent tapered reading with plastic
gauge.
On the edge of the gauging plastic envelope
there is a graduated scale which is correlated in
thousandths of an inch. Without removing the
gauging plastic, measure its compressed width
(at the widest point) with the graduations on the
gauging plastic envelope as shown.
9. Measure crankshaft end play (see “Specifica-
tions”) by forcing the crankshaft to the extreme
front position. Measure at the front end of the rear
main bearing with a feeler gauge as shown.
a
a
b
72557
a - Compressed Gauging Plastic
b - Graduated Scale
72543
a - Measuring Crankshaft End Play - (Force Crankshaft To
Extreme Forward Position )
NOTE:Normally main bearing journals wear evenly
and are not out of round. However, if a bearing is be-
ing fitted to an out-of-round journal (.001 in. 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 .001 in., interference be-
tween the bearing and journal will result in rapid
bearing failure. If the flattened gauging plastic tapers
toward the middle or ends, there is a difference in
clearance indicating taper, low spot or other irregu-
larity of the bearing or journal. Be sure to measure
the journal with a micrometer if the flattened gauging
plastic indicates more than .001 in. difference.
Replacement
NOTE:Main bearings may be replaced with or with-
out removing crankshaft.
a
b
c
6.
If the bearing clearance is within specifications,
the bearing insert is satisfactory. If the clearance
is not within specifications, replace the insert. Al-
ways replace both upper and lower inserts as a
unit.
72359
Main Bearing Inserts
a - Lower Bearing Insert (Install In Cap)
b - Upper Bearing Insert (Install In Block)
c - Oil Groove
7.
A standard, or .001 in., undersize bearing may
producetheproperclearance.Ifnot,itwillbenec-
essary to regrind the crankshaft journal for use
with the next undersize bearing.
After selecting new bearing, recheck clearance.
Index
3A-46 - 454 C.I.D. (7.4L) / 502 C.I.D. (8.2L)
90-823224--2 796
| Categories | Mercury MerCruiser Manuals |
|---|---|
| Tags | Mercury MerCruiser 454 CID, Mercury MerCruiser 502 CID |
| Model Year | 1993, 1994, 1995, 1996, 1997 |
| Download File |
|
| Document File Type | |
| Copyright | Attribution Non-commercial |
(4 votes, average: 4.5 out of 5)
Marine readers have rated 1993 1997 Mercury-MerCruiser GM V8 454 CID 7.4L and 502 CID 8.2L Marine Engines Service Manual Number 16 4.5 out of 5.0 based on 4 product reviews. Hugely helpful service manual! Perfect. Thank you!
Manuals are all Important for Technician
This book is invaluable if you do your own repairs. Great book.
Could not find a copy until a search brought me here.
Excellent print.
Thank you