Lynn,
Forgive me if I am a little dense but after your
explanation and all the mention of torque
readings based on "Dry Threads" then your statement to use "Antiseize"
which method
produces the most accurate and repeatable torque readings
??............In my hunt for bolts
of the correct thread length for the "Dynaocal" mounts to bolt to
my "Mistral" backplate to
my engine mount I obtained a lot of info regarding bolt torque
from the "ARP" (well known
fastener company)........Their torque procedure recommendation
includes the use of their
own brand of thread lubricant...............
Kelly Troyer
"DYKE DELTA JD2"
(Eventually)
Well, any method of installation that is consistent bolt to bolt and hole
to hole can then produce repeatable torque readings within some acceptable
range. All dry holes in one range, or all motor oiled holes or many builders
like STP because it clings to stuff so well. So, there is a big range in
tension developed between say 25 pounds of torque on a bolt with clean dry
threads in a clean dry hole (Vapor degreased) and another bolt lubricated with
nearly any kind of oil or, oil like product.
Then all of the oil like products will produce a very much narrower band
of tension outcomes. I like Nickel anti-seize, but nearly anything works. So
if the bolt is torqued up and you find some below torque, back each out in
sequence one full turn to allow some lube to migrate onto the threads and
torque up in one continuous motion. If you have to stop the motion before the
wrench clicks, then back up one full turn and try again.
If it was not a single motion from the last torque step to the wrench
click, then the bolt has not been torqued and shame on you.
Torque is called out to control some other factor. In this case how much
pressure is on the stack, and that controls beam stiffness and some torsional
stiffness.
In very highly stressed bolts in tension, the bolt is torqued into a
tensile stress above the maximum load expected. SPS (Standard Pressed Steel)
makes all kinds of bolts. The great tension bolts have a dimple on
both ends. You stick a special dial indicator jig on these bolts and you
torque the bolt until it has stretched a specific amount, like .007" for rod
bolts. It is best to have a spare set of SPS bolts that you use just during
resizing you rods. The clown who runs that machine generally torques rod bolts
to 35 pounds for everything.
You want you rods resized with bolts close to 50 pounds and stretched to
.007" That is if you actually want round big ends. (Higher HP and lower
oil temps).
The torque callouts for most bolts have nothing to do with the bolts at
all. It is to prevent your ham fisted brother in-law from jacking the threads
out of an aluminum casting. So bolts in aluminum for most applications can be
made of crap. Since not into their working range, there is no way to keep them
from backing out without some positive locking system. Not Locktite as it will
glue the bolt in tight and require much heat to kill it before removal, lest
the threads come out with the bolt.