My point, Jim, was that the average lister - whose demonstrated grasp of
auto mechanics is pretty low-level, judging by the questions asked on the
list - would not be able to judge whether the head studs are any good simply
by looking at them. Chances are they would also lack your years of
experience in dealing with metals and rebuilding more than one engine a year
just for the love of it.
Having to rebuild an engine more than once due to a blown head gasket caused
by weak head studs is a particular annoyance - especially to the neophyte
builder who is already struggling to make sense of confusing directions and
a variety of opinions offered on the list. Therefore, rather than refer to
shop manual advice that says studs can be re-used (but not stating that they
should not be re-used indefinitely, and written without the writer ever
imagining that these cars would last 40 or more years and undergo numerous
rebuilds), for the $40 or so cost of a set of new studs, I would recommend
that head studs be replaced on every engine rebuild unless the rebuilder
knows that the existing studs have been torqued down only two or three
times.
Lawrie
British Sportscar Center
-----Original Message-----
From: James H. Nazarian, Ph.D. <microdoc@apk.net>
To: Lawrie Alexander <Lawrie@britcars.com>
Cc: mgs@autox.team.net <mgs@autox.team.net>
Date: Wednesday, January 17, 2001 7:36 AM
Subject: Re: Head Studs (long reply)
>Good Morning Lawrie,
>
>Have you recently caught something from Ed? In answer to your first
question
>regarding experience, I have only some 30 years work experience under my
belt
>involved in metrology and non-destructive testing, including 3 patents and
four
>copyrights for automated test and measurement instrumentation and software.
I
>have rebuilt a mere 25 British engines during the past 17 years. Thanks for
>asking, but my statement regarding head studs was based not entirely upon
>experience, but on original MG reference materials. On to your next
questions.
>
>"How many times can used head studs be re-used safely"...
>
>The answer: until they are damaged, worn out or no longer meet the criteria
that
>determines suitability.
>
>"how, by looking at an engine that you've just taken apart for the first
time,
>can you determine how many times the studs there have already been
re-torqued?
>
>The answer: you probably can't.
>
>Books have been written on the subject of fasteners, and I will not bother
>writing another. If you or anyone else wants more information, please send
an
>e-mail to me off-line.
>
>Your questions are somewhat nebulous: it is less important to know how many
>times a head stud has been reused then it is to know if it should be reused
at
>all. According to my limited reference materials including original
workshop
>manuals and parts lists for MGA, MGA Twin Cam and MGB studs that fasten the
head
>to the block on these engines, do not require replacement during a rebuild
>unless the threads have been damaged in some way. I chose to adhere to MG's
>recommendations, check the original and stay with it if it passes
inspection
>especially when the available replacements are known to be of inconsistent
>quality. Of course, you can follow whatever course you chose to take.
>
>Jim (the elder)
>I've rebuilt engines purely for the love of it
>
>Lawrie Alexander wrote:
>
>> May I ask on what experience you base that statement, Jim? And the
following
>> btwo questions would also seem important - How many times can used head
studs
>> be re-used safely, and how, by looking at an engine that you've just
taken
>> apart for the first time, can you determine how many times the studs
there
>> have already been re-torqued?
>>
>> Lawrie
>> British Sportscar Center
>> (Who has no Ph.D but forty years of engine building experience)
>>
>> -----Original Message-----
>> From: James H. Nazarian, Ph.D. <microdoc@apk.net>
>> To: Baker, G. <gbaker@customcpu.com>
>> Cc: MG Board <mgs@autox.team.net>
>> Date: Tuesday, January 16, 2001 5:52 AM
>> Subject: Re: Head Studs
>>
>> >This is true with certain cars, particularly newer American makes, but
it
>> >is not true of pre-1980 MGs, or Healeys. We definitely can re-use studs.
>> >
>> >Jim
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