Hydraulic valve lifters require little attention. Lifters
are extremely simple in design. Normally, readjust-
ments are not necessary and servicing requires only
that care and cleanliness be exercised in the handl-
ing of parts.
In most cases, where noise exists in one or more lift-
ers, all lifter units should be removed, disassembled,
cleaned in solvent, reassembled and reinstalled in
engine. If dirt, corrosion, carbon, etc., is shown to ex-
ist in one unit, it more likely exists in all the units; thus
it would only be a matter of time before all lifters
caused trouble.
Locating Noisy Lifters
Locate a noisy valve lifter by using a piece of garden
hose approximately 4 ft. (1.2 m) in length. Place one
end of hose near end of each intake and exhaust
valve, with other end of hose to the ear. In this man-
ner, sound is localized, making it easy to determine
which lifter is at fault.
Removal
IMPORTANT: Keep push rod and hydraulic valve
lifter from each valve together as a matched set
and mark them so they can be reinstalled in the
same location later.
Another method is to place a finger on face of valve
spring retainer. If lifter is not functioning properly, a
distinct shock will be felt when valve returns to its
seat.
Remove as outlined:
1. Remove rocker arm covers.
2. Remove intake manifold.
General types of valve lifter noise are as follows:
1.
Hard rapping noise - usually caused by plunger
becoming tight in bore of lifter body so that return
spring cannot push plunger back up to working
position. Probable causes are:
3. Remove rocker arm assemblies and push rods.
4.
Remove valve lifters.
NOTE:Gen VI engines with roller lifters have addi-
tional valve train components shown below.
a. Excessive varnish or carbon deposit, causing
abnormal stickiness.
b
b. Galling or “pickup” between plunger and bore
of lifter body, usually caused by an abrasive
piece of dirt or metal wedged between plung-
er and lifter body.
a
2.
Moderate rapping noise - probable causes are:
a. Excessively high leakdown rate.
b. Leaky check valve seat.
72329
c. Improper adjustment.
a - Lifter Restrictor Retainer
b - Fasteners
3.
4.
General noise throughout valve train - this will, in
most cases, be a definite indication of insufficient
oil supply or improper adjustment.
a
Intermittent clicking - probable causes are:
b
a. A microscopic piece of dirt momentarily
caught between ball seat and check valve
ball.
b. In rare cases, ball itself may be out of round
or have a flat spot.
72340
a - Roller Lifter Restrictor
b - Roller Lifter
c. Improper adjustment.
5.
6.
Remove lifter restrictors on roller lifters models.
Remove valve lifters.
Index
90-823224--2
796
454 CID (7.4L) / 502 CID (8.2L) - 3A-25
| 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