Hi folks,
Just thought I'd tell you about some engine stud anomalies that I've run
into during the rebuild of my engine.
1) Soft rocket bracket studs. While torquing down the rocker bracket nuts I
sensed that something wasn't quite right when I tried to go from 20 to 25 ft-lbs
on the front stud. I stopped and pulled things apart. The stud was actually
elongating itself below the nut! Had I continued to twist the wrench, I have no
doubt that the stud would have broken. This was a brand new stud (Moss
#329-980) purchased from a Moss distributor. (I bought a complete set of new
engine studs for the rebuild.) I noticed that the two long rocker bracket studs
didn't show any type of nitride finish, just shiny steel. I'm very glad that I
didn't try to hoist the engine via these studs for reinstallation. That would
have been catastrophic. You might want to cast a leery eye on any studs that
you get that don't show some sort of treatment to the surface.
2) Short head studs. Tonight I intended to install the head with a new set of
cylinder head studs. (I replaced the faulty rocker bracket studs.) Even before
I got the torque up to 40 ft-lbs I could see that something was amiss on the
short studs. There wasn't any thread showing above the nuts. I'm from the old
mil-spec school that says that there should be between 1.5 and 2.5 threads
showing after the nut. In this case the end of the stud was virtually flush
with the top of the nut! I pulled things apart and measured the studs (Moss
#328-950). The new ones had a mean length of 4.482". The old ones measured
4.552". The threads are 3/8-24, which is about .042"/thread, so this difference
of .07" is about 1.7 threads. I put the old studs back in!
--
Bud Krueger
http://home.ici.net/~bkrueger/
52TD
77MGB
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