(Excuse me if this is a duplicate, my e-mail was malfunctioning and I am
resending).
I've been away from the list for a long time. Just getting the Spit back on
the road and ran into a problem not encountered before.
I was refitting the head after valve renewal, using new studs purchased from
a reputable supplier. 3 head nuts would not come to torque, one of the
studs broke w/ot reaching torque. And it appears one of the other 2 studs
(at least) started to strip in the head.
I checked the torque with two different wrenches, both of which I use
regularly, so I'm pretty certain it was not over-torque.
This is a combination of events that has left me confused. Some questions
have arisen from this novel experience (I've done this operation many times
for this and other engines with no problems ever.).
1. From my present confused state of mind, I'm wondering which end of
the stud goes in the block, long or short threads. Been doing it the same
way forever, but . . .
2. I have been told that the proper head nuts are a grade 5, assuming
the studs are a grade 8. This is contrary to fastener industry doctrine
which - as I read it - says that a nut should be at least as strong as the
bolt/stud. i.e. a grade five could be fit to a grade five or lower.
Because the studs are reported to be grade 8, I purchased grade 8 nuts for
the next attempt.
My plan is to proceed with reassembly again. I have checked the block
threads as well I can visually and by running a tap gently in each hole with
light lubrication and have blown the debris from the holes. The threads
appear ok.
Any insight would be appreciated.
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Spitfires@autox.team.net
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