[Vwdiesel] Diesel Headgasket

[Val Christian]

There appear to be some concepts reemerging around creating more longevity
in the head gasket interface.

Some time ago, there was a tendancy to fine grind, almost to a polish, 
heads.  The idea was that there could be a small ammount of creep with 
temperature change.  Later, that smoothness was blamed for failed 
headgaskets, and the idea was that the smooth head sliding, was burnishing
the headgasket, encouraging failure through leakage.

Now the school of thought seems to be having a rough, blade cut head, and
using a dry gasket, where the blade cut eats into the gasket, and the 
plastic changes are within the gasket, and not at the interfacing surfaces.

Go figure.  I'm not a materials science person, and I figure it's somewhat
the method d'jour.  

I will say that the current directions with the most recent head gasket,
call for dry application (no spray on mastics, etc.) and the blade
cut rough head surface.  We'll see if it works better.  Personally, I
would rather pay a few more dollars at initial vehicle purchase for 
a cast head.

Val




> 
> VW had pure hell trying to make a gasket work -- due to the difference =
> in expansion.
> Head to block.
> 
> They never really solved the problems as far as I am conserned. ---- =20
> 
> A block made of Aluminium is the answer.---- or for old Rabbits ? a cast =
> iron head.
> 
> As a short tem solution ? keep a COOL head.
> 
> Hagar.
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