Ken
As you know I glass bead some engine parts and heads when I rebuild them
I learned long ago that blind holes collect and trap glass bead. the problem with this is that the bolt hole is shorter when the bottom is full of glass bead and just as you thing the bolt is tight it brakes off in your hand. using used parts and hardware can be tricky  the lessons we have learned are the bolts we have broken but they are only a lesson if we learn something. I do a couple of things to clean and check threaded holes. first I make sure the parts are dry before I glass bead them. second I blow the hole out with air pressure always with safety goggles. third I chase the hole with a thread chaser or a fairly new tap (I dont trust old taps) and I use a taping fluid. taps tend to remove metal and can weaken threads  new hardware is always a good idea as is wire brushing any old bolts that must be reused. it is way easier and faster to go to the hardware store for new bolts and nuts than to go to the hardware store for drills and tap extractors. If you are not sure that a nut is tight to begin with or that a bolt is not all the way down in the hole then TAKE IT APART AND CHECK IT OUT

a couple of problems I have seen worth pointing out on the vanagon engines
the bolt for the front pulley locks up before the pulley is tight I cant explain why this keeps coming up but I have had to chase the threads in the crank and add washers to get the pulley secure there does not seem to be more than one bolt length
the head nuts as you mentioned can twist and moan as they get torqued and they even snap off if the stud is rusted.
you cant add oil and sealant to the threads it will never seal. I chase the threads and inspect the blind hole in the head nut and tap it out if needed I always run a wire bottle brush threw the head nut threads. When the head nuts bind I remove the nut and add a small amount of sealant to the threads as a lube keep in mind that any sealant that gets between the top of the stud and the nut has the potential to bind and give a false reading as to the torque values. one last note I have have seen the AMC heads strip the threads for the exhaust when the exhaust is installed and the bolt is tightened the problem is not the heads but the bolt is to short I use a 30 mm lenght bolt and a flat washer I may not look like it will tighten but it does for this reason all my engines come with the hardware to hang the exhasut on the heads
Bob Donalds
http://www.bostonengine.com
as always
all rights reserved
 
 

 
KENWILFY@aol.com wrote:

Bob, thanks for sharing.  It is always great to learn something new and I did
today.  I want your opinion on something though.  I had always been told in
Aviation Mechanics School that when you torque fasteners you do not use any
lubrication unless the manual specified it.  However in the article, what
this guy says makes sense.  How can you know that the resistance you are
getting and that is being measured by the torque wrench is not just the
resistance of a stubborn fastener instead of the fastener actually being
tight?  I never used any lube when putting waterboxer head nuts on simply
because nothing in Bentley talks about it.  Should I be using 30 wt oil?
What has your experience been?

Thanks,
Ken Wilford
John 3:16
www.vanagain.com
Phone: (856)-765-1583
Fax: (856)-327-2242