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ZekesterbluH3
06-28-2013, 08:03 AM
Not a Donzi question, but a big block Merc question...

It appears the starboard 454 (inboard with hurth transmission) in my 91 Searay express is moving. I'm looking at the saddle mounts for sagging, but there is evidence of shifting and sliding on the pins of the mounts themselves. Does anyone have the torque specs for the mounts, I found specs for the mounts to the block, but need specs for the rest. There are 4 mounts bolted to the block, each mount slides in and out of a second bracket that is clamped by a nut and bolt, this second bracket is held to the stringers with 1-1/16" nuts.

I have the mount to block specs, but require the torque specs for the nut and bolt , and the torque specs for the big nuts.

Any help would be appreciated.

Sidney073
07-01-2013, 06:16 AM
This is the universal standard for bolt torque when a spec is not available.
BOLT TORQUE SPECIFICATIONS, Unified Standard -- UT-120

When the Workshop Manual does not give a torque specification for a fastener, use the standard torque numbers in the following table. Unless otherwise specified, all threaded fasteners in the MGA will be equal to Unified Grade 5. There should be no Grade 2 fasteners anywhere in the car. Most of the torque specifications given in the Workshop Manual will be higher than Grade 5 in this table, because those fasteners are (originally) better than Grade 5.



BOLT TORQUE SPECIFICATIONS - For Unified Standard Threads
Torque in pounds-foot


Fastener
Grade >>>
2
5
7
8
Socket head
cap screw


Bolt
Dia.
Threads
per inch
Dry
Oiled
Dry
Oiled
Dry
Oiled
Dry
Oiled
Dry
Oiled


1/4
20
4
3
8
6
10
8
12
9
14
11


1/4
28
6
4
10
7
12
9
14
10
16
13


5/16
18
9
7
17
13
21
16
25
18
29
23


5/16
24
12
9
19
14
24
18
29
20
33
26


3/8
16
16
12
30
23
40
30
45
35
49
39


3/8
24
22
16
35
25
45
35
50
40
54
44


7/16
14
24
17
50
35
60
45
70
55
76
61


7/16
20
34
26
55
40
70
50
80
60
85
68


1/2
13
38
31
75
55
95
70
110
80
113
90


1/2
20
52
42
90
65
100
80
120
90
126
100


9/16
12
52
42
110
80
135
100
150
110
163
130


9/16
18
71
57
120
90
150
110
170
130
181
144


5/8
11
98
78
150
110
190
140
220
170
230
184


5/8
18
115
>93
180
130
210
160
240
180
255
204


3/4
10
157
121
260
200
320
240
380
280
400
320


3/4
16
180
133
300
220
360
280
420
320
440
350


7/8
9
210
160
430
320
520
400
600
460
640
510


7/8
14
230
177
470
360
580
440
660
500
700
560


1
8
320
240
640
480
800
600
900
680
980
780


1
12
350
265
710
530
860
666
990
740
1060
845



Baseline torque is calculated for a non-lubricated, un-plated bolt.



BOLT TORQUE FACTORS


LUBRICANT OR PLATING
TORQUE CHANGES


Oil
Reduce torque 15% to 25%


Dry Film (Teflon or moly based)
Reduce torque 50%


Dry Wax (Cetyl alcohol)
Reduce torque 50%


Chrome plating
No change


Cadmium plating
Reduce torque 25%


Zinc plating
Reduce torque 15%



Hope this helps,
Sid