[Vwdiesel] Cracked block --- ??? ( more inf )

[James Hansen]

Usually the heads crack during torqueing because the hole was not properly
cleaned out.  Oil, coolant, etc gets in the hole, and when the head fastener
is installed, the hydraulic pressure of the fastener dead ending on the
fluid leaves out the most accessible conduit- which is straight out the
weakest spot, the side, causing a crack.
Holes should be chased with a tap, and sucked out, washed with your favorite
juice, and sucked clean again.
The block is just a fine grain cast iron that has been common to european
blocks for a looooong time, not so with the NA stuff. Why they break from
inside out, not outside in, is more area to transfer the force over when you
push in from the outside such as you did with your punch.  Even tho the
punch was small, the cast had a whole block to push back at you with. When
pushing from the inside out such as hydraulic locking a stud installation,
you are straining a relatively thin layer that has only air for backing.
As to malleable cast, what it is, and terms, these guys are much more
eloquent than I.  http://www.key-to-steel.com/Articles/Art96.htm

-James



> -----Original Message-----
> From: vwdiesel-admin at vwfans.com [mailto:vwdiesel-admin at vwfans.com]On
> Behalf Of H .Hagar
> Sent: Saturday, July 26, 2003 6:56 PM
> To: vwdiesel at vwfans.com
> Subject: [Vwdiesel] Cracked block --- ??? ( more inf )
>
>
> This is a multi-part message in MIME format.
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> [ Picked text/plain from multipart/alternative ]
> After this afternoon I have a deep respect for VW cast iron  ---
> the type they use in the block of 1.5L 1980.     Calling James
> Hansen we need you.    Firstly the area under suspicion is the
> corner headbolt hole by injection pump. The cooling gallery can
> be inspected using the sun and a mirror ---I did that.
> The end of the block is milled smooth.  and to me the wall looked
> thin. So the hick  ehhh Hillbilly I am I figured a big hammer and
> a drift would go through the wall to see what is what. Let me
> tell you fellas no way   ----It is strong and malleable (is that
> the right word James ?)   Somehow the word nickel popped up in my
> head.---Now knowing that the Germans are sneaky ---the bolthole
> that broke at the other end ,the break looked like  pot belly
> stove stuff.  So I beat the living snot out of that end ----same thing.
> That brings up new questions of why the blocks break on torqueing
> the head down.         Hagar
>
> PS:  There are two small tapped holes in the area so I messured
> how deep. --at or about 3/4 inch.
> --
>
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