Header HELP! new longer exh. man studs?

[rocco16v at netzero.net (L F)]

Hmmmm....since you asked:  :)

I think the belleville washers may be a good idea, better than just a solid spacer in theory. (you even spelled belleville correctly...I am impressed!)
The only problem would be that you'd have to torque the nut down all the way, at which point the belleville washers would effectively become a solid stack.  
I'm not sure that "loosening" the clamping force on the manifold (through thermal expansion) is the best answer (leaks, fretting, etc....).  If I were having problems with a cracking manifold flange, I think I'd attempt to brace the outlet end of said manifold to the block with a hefty support.  (Most of the cracked manifolds I've seen were not cracked at the flange, but at a high-temp area further downstream.)

  That said, it sounds like a pretty easy and inexpensive 'fix' if you feel the need and belleville washers can be had at McMaster.

Larry

----- Original Message ----- 
  From: Ron Pieper 
  To: VWGTIKIM@aol.com ; peter@thescirocco.com ; rocco16v@netzero.net ; scirocco-l@scirocco.org 
  Sent: Monday, January 12, 2004 9:38 AM
  Subject: Re: Header HELP! new longer exh. man studs?


  This may be a twist on this topic (haven't read it all), but WTH.  

  I've heard something that seems a bit odd...that switching to longer exhaust manifold studs and
  putting bushings (read: stacks of washers) under the nut to fill up the space is supposed to
  eliminate cracking of the manifold flange.  This is supposed to be a trick used on Saab turbo and
  heavy-duty diesel engines.  I'm supposing that the longer stud expands more, providing more
  'give', and thus preventing cracking.

  Makes me think that a longer stud and a stack of belleville washers may do this just fine, and
  cheap too.  Hmmmm....anybody (Larry) have an opinon on this?

  Ron

  --- VWGTIKIM@aol.com wrote:
  > In regard to the question on the headers, what they did was use a collar  the 
  > same thickness of the manifold plate that mounts to the head, and weld the 
  > collars around each of the 4 pipes. In my previous experiences with headers 
  > cracking this is where it has been. Michael


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