Blake,
You may want to address this question to Skip Kelsey at Shadetree
Motors
http://www.shadetreemotors.com/
In theory, one does not need any kind of lock washer or any other
locking device on a properly torqued fastener. However, being one who
has personally experienced the ravages of a broken rod pinch bolt, I
will continue to use some kind of locking device when installing them.
I doubt that the the stress from the lock washer is at all unbalanced
once the correct torque value is reached and the unbalance when it is
first engaged would not make any difference on a high tensile strength
bolt. The lock washers supplied with these bolts ar high tensile
strength or hardened washers. Skip Kelsey supplies a allen head cap
screw to use in the pinch bolt application, which eliminates the need to
machine down the wall of a socket to fit the close quarters found at the
small end of the rod. These bolts that he supplies are ATP Unbrako
bolts that are rated at 190,000 PSI, so should be quite good. One
further item in talking about the pinch bolts, The torque spec given in
the shop manual for the TD and TF and in the Woods manual is wrong and
will lead to broken pinch bolts and all the accompanying bad things that
go along with a thrown rod. Both the shop manual and Woods manual call
for a torque of 33 ftlbs .. The proper torque, according to all torque
tables that I have seen and to Skip Kelsey and Mike O'Connor of C'Connor
Classic Autos is 25 ftlbs.
Good luck,
Dave
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