1.
2.
Measure valve stem diameter of old valve being
replaced and select proper size valve guide
reamer from chart below.
Valve Seat Repair
Valve seat reconditioning is very important, since
seating of valves must be perfect for engine to deliver
maximum power and performance.
Standard Valve
Stem Diameter
Reamer Required For
.015 In. Oversize Valve
Another important factor is valve head cooling. Good
contact between each valve and its seat in head is
important to ensure that heat in valve head will be
properly dispersed.
.372
In.
J-7049
Ream valve guide bores, as shown.
Several different types of equipment are available for
reseating valve seats. Equipment manufacturer’s
recommendations should be followed carefully to at-
tain proper results.
a
d
b
c
72927
50668
Typical “3 Angle” Valve Seat
3.
Remove the sharp corner created by reamer at
top of valve guide.
a - Top Angle (30°)
b - Seat Angle (46°)
c - Bottom Angle (60°)
Valve Springs - Checking Tension
d - Seat Width
IIntake - .060-.090 in (1.52-2.29 mm)
Exhaust - .060-.090 in (1.52-2.29 mm)
NOTE:On 7.4L models, spring tension must be
tested with damper removed. All other models re-
quire testing with dampers installed. Refer to “Speci-
fications.”
Regardless of type of equipment, however, it is es-
sential that valve guide bores be free from carbon or
dirt to achieve proper centering of pilot in valve guide,
ensuring concentricity.
IMPORTANT: Springs should be replaced if not
within 10 lb. (44 N) of specified tension.
b
a
72308
72568
Measuring Valve Seat Concentricity
a - Valve Spring Tester (J-8056)
b - Torque Wrench
Index
3A-32 - 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