<VV> engine rebuild-safe removal of cylinder studs

[Larry Forman]

At 05:55 PM 8/13/2005 -0700, David McMillan wrote:
>Go easy on me if this seems naive.
>
>I'm in the process of dismantling my motor and will be
>splitting the block. Just wondering what the safest
>way to remove the cylinder studs is. Did I read
>somewhere that double nutting is not good? Is there a
>special tool for doing this? I know from the shop
>manual that there is one for installing them...
>
>Thanks,
>Dave

Hi Dave,
I first need to ask, why are you attempting to remove the cylinder 
studs?  They normally remain with each half of the block and most people 
recommend leaving them intact if they are OK.

That said, I remove them all the time and it is not a fun task and it is 
risky.  The really BAD thing is for the stud to break right at the 
case.  That can often trash the block, since it is quite difficult to 
remove just the broken off flush part.  Also, the studs are quite hard, so 
they are difficult to drill into lengthwise.

I approach I use is to double nut the stud and use two wrenches locked 
together by your firm grip and see if you can break it loose.  They often 
will make a loud crack when they come loose.  Often, they will remove some 
of the aluminum and require an insert.  Since the reason I remove them is 
that I plan on using a Timesert, then no issues, since the threads will be 
drilled out anyway.

What happens when it does not want to budge?  If you keep trying, either 
the stud will break (as in BAD) or it might first corkscrew.  Which is not 
much better.  When it appears to be stuck, I will use an oxy acetylene 
torch to WARM the block and studs.  This destroys the heat treating of the 
studs and you should know that and not reuse them without heat treating 
them.  Also, I need to be careful not to melt the aluminum, since it will 
not glow cherry red like steel prior to melting.

Still, I love using the Timeserts for this application since I can replace 
a stud if needed and they appear to never strip out of the block, like I 
have had on numerous occasions for the stock studs.

Also, if you plan on using a Timesert, there is a special extra long one 
for the Corvair case and that should be used.  VERY IMPORTANTLY, you will 
need to "chase" the threads of the stud prior to inserting it into the 
Timesert.  This is because the stud has a special interference thread for 
the aluminum and will bind in the Timesert and then rip it out of the 
block, generally destroying that block.  I can guarantee this to 
happen.  As for "chasing" the threads, it takes a very good quality die and 
after just a very few studs, will destroy that die.  They get "creaky" and 
are no good.  Plan on about a maximum of six studs chased for a new die 
before replacing it.  Preventing the stud from turning is a challenge 
too.  I use a heavy leather piece in a large vice, and two grade 8 nuts 
locked with two wrenches.  You do not want to have the vice score the stud 
since that will weaken it and create a stress concentration and it is more 
liable to break in service.

This is a complicated operation to be avoided unless you REALLY plan on 
using an insert, so then otherwise leave them alone.
Regards,
Larry