After reading the ARP catalogue through several times and being
duly scared by the dire warnings of the terrible consequences of
under or over torqueing my fasteners.
This is my understanding of the situation, I would appreciate
corroboration of my assumptions. As I said the application is
a 1969 MGB with a 5 main engine and the earlier (diagonally split)
style con-rods where only one of the bolt holes goes all of
the way through.
It is my understanding (though I can't remember where I read it)
that the con-rod bolts should not be used with the lock tab.
Without the flats of the hex bolt there is little for the lock
tab to grab onto and it would distort the torque and stretch
readings anyways.
It is my understanding that stretch can only be determined when
the guage can get to both ends of the bolt, therefore it could
not be used on half of the con rod bolts anyways.
Page 24, in a special note says to refer to "Friction Facts"
on page 14. Page 14 is a glossary of technical terms.
Con rod bolt: ARP p./n 206-6003 torque is 44 ft-lb stretch is .0065 to .007
Seven says all fasteners are the 190,000 PSI strength.
Page 12 says the torque values represented here are intended to
be for general information, not for specific installations.In
special installations where supplied instrucitons deviate fromt he
torque valued reccomended here, always follow the instructions.
Seven just shipped me the page out of the catalogue.
I understand this to mean to use the page out of the catalogue.
Page 11 says that lube can reduce the required torque by 20-30%.
I am assuming that this does NOT mean that if I use ARP fasteners
with moly I should torque to %70-80 of the factory spec, as the
factory spec was written for different fasteners.
The instructions do not say whether the chamfer on the washer
should face the nut or the main cap.
It is my understanding that with a cast iron (as opposed to
aluminum) block, the limiting factor on the torque is the
fastener and not the block.
torque torque
Application P/N size oil moly factory
Head Stud 206-4202 3/8 50 39 45-50
Main Stud 206-5403 1/2 122 95 70
con-rod bolt 206-6003 5/16 44 35-40
^^
use these
Thanks a bunch
Larry
lrc@red4est.com
|