<VV> Head studs

[BobHelt at aol.com]

Hi Mel,
Below are my opinions developed over some 40 years of working on  Corvairs.
Regards,
Bob Helt
 
In a message dated 8/30/2008 7:04:18 AM US Mountain Standard Time,  
mherwald at mgwnet.com writes:

Now the  reason for this post. I have a few questions. Here  goes.



1)      What class of thread is on the end  of the stud? I’m guessing it’s a
class3. What are the specs on these  threads?
 
I don't know the class, but these are special interference threads at the  
case end of the studs. these threads are to prevent oil from seeping there. the  
holes in the case are probably special too and you should not run a tap thru  
them or it will destroy them. Same for the studs...no die either.



2)      How would one test the threads on the  end of the stud short of a
go/nogo gage for this thread class? They looked  perfect.
Run them into the case measuring the torque required to do so. The spec  
limits are in the shop manual



3)      Should one never use used  studs?
 
Use them if they seem good but the the threads on the nut end must be in  
good shape. And the studs should have no marks, indentations, or scores on their  
surfaces that might be fracture-initiating points.



4)      Should I have run a tap thru the case  holes where the studs attach?
The tap seemed to work  fine.
 
No. NEVER



5)      Why did some studs go in well while  others were much harder? What
happened to them? Did it have something to do  with the way they came out?
 
No sure. They may have been oversize studs, avail from the dealers were 003  
and 006 OS.



6)      Are the threads in the case standard  class 2 threads?
 
don't know what a class 2 is.





I don’t want to ever have a repeat of this and would  like to understand what
was going on. I’m hoping some of you have been thru  this before and can shed
some light on this for me.
A suggestion. The threads are designed to prevent leaks so I would not use  
any loctite on them at all.



Thank you.



Mel  Herwald








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