Inspection
b. Holding valve head off seat about 1/16 in. (2
mm), move valve stem back and forth in di-
rection shown. Compare stem clearance with
specifications.
1.
Inspect cylinder heads for cracks in exhaust
ports, water jackets, and combustion chambers
(especially around spark plug holes and valve
seats). Replace heads if any cracks are found.
2.
Inspect cylinder head gasket surface for burrs,
nicks, or erosion or other damage. Also, check
flatness of cylinder head gasket surface, using a
machinist’s straight edge and feeler gauges as
shown. Refer to “Specifications.”
a
c
b
c
b
a
72566
72563
a - Straight Edge
b - Feeler Gauge
c - Take Both Measurements Diagonally Across Head (Both
Ways) And Straight Down Center Of The Head
a - Valve Stem
b - Dial Indicator
c - Valve Guide
c. If clearance exceeds specifications, it will be
IMPORTANT: Cylinder head-to-block gasket sur-
face should be resurfaced if warped more than
specified. When head resurfacing is required,
cylinder head-to-intake manifold gasket surface
on head must be milled to provide proper align-
ment between intake manifold and head.
necessary to ream valve guides for oversized
valves, as outlined under “Valve Guide Bore
Repair.”
Valve Guide Bore Repair
3.
Inspect valves for burned heads, cracked faces
or damaged stems.
IMPORTANT: Be sure to measure valve stem di-
ameter of both the intake and exhaust valve, as
valve stem diameter may or may not be the same
for both valves.
4.
Inspect rocker arm bolts and push rod guides for
wear and damage.
IMPORTANT: Excessive valve stem to bore clear-
ance will cause excessive oil consumption and
possible valve breakage. Insufficient clearance
will result in noisy and sticky valves.
If .015 in. oversize valves are required, ream valve
guide bores for oversize valves, as follows:
5.
Measure valve stem clearance as follows:
a. Attach a dial indicator to cylinder head, posi-
tioning it against the valve stem and close to
the valve guide.
Index
90-823224--2
796
454 CID (7.4L) / 502 CID (8.2L) - 3A-31
| 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