[V8] Retorqueing heads

[Dag Bøsterud]

As I've explained in my other thread (V8 leaking oil... again... and again..), I've just replaced the head gaskets, along with about every other gasket in the engine.

The engine was leak free for about 200-300 km, then it started to leak again.
This is why I'm wondering how you people feel about overtorqueing the heads.
I've done this to lots of engines, but they never had stretch bolts and the block were made out of cast iron.

/Dag
92 V8 4.2
202 000 miles - not completely leak free...
  ----- Original Message ----- 
  From: QSHIPQ at aol.com 
  To: David.Coleman at blackrock.com ; dag.boesterud at consulgranada.net ; V8 at audifans.com 
  Sent: Friday, May 16, 2008 4:09 PM
  Subject: Re: [V8] Retorqueing heads


  I'm late too...  Here's what I'd try in the cheap sneak and pray.

  Buy a set of new head bolts.  Pull each bolt out 1 at a time, and replace with a new one and torque to factory spec.  

  Head bolts are stretch bolts, I measured a set once, they stretch something in the hood of 5mm+ torqued.  Once heat cycled, your risk of snapping one increases exponentially, so does the risk of ruining the head, and/or ruining the block.  Chances are really good you need to go in and replace the head gasket.  The *only* other way I'd consider doing this is to do 5 hail mary's, and replace the bolts 1 at a time (start with the center and follow the bolt replacement as you would the torque procedure) and torque each completely to final spec, move on to the next.  Good luck....

  HTH and my .02

  Scott J
  QSHIPQ 
  In a message dated 5/16/2008 8:24:25 A.M. Central Daylight Time, David.Coleman at blackrock.com writes:
    Just out of curiosity, as I haven't been following this thread...

    Have you ever torqued down a V8 cylinder head?  The specs are massive, and going that last factory-spec 1/4 turn as specified in the Bentley is harrowing, to me at least.   I felt like I was either going to snap the wrench, the bolt, or spin the whole car around.

    I guess before worrying about *over* torquing it, consider two things:

    - check to make sure it's in spec first..
    - perhaps get a new set of head bolts and replace them all, rather than retorquing the existing ones (which are supposed to be replaced, not reused).

    Again, I'm late to the party here, so please don't act on my two cents alone.

    -davec


    > -----Original Message-----
    > From: v8-bounces at audifans.com [mailto:v8-bounces at audifans.com] On Behalf Of
    > Dag Bøsterud
    > Sent: Friday, May 16, 2008 9:16 AM
    > To: V8 at audifans.com
    > Subject: [V8] Retorqueing heads
    > 
    > If I were to torque the cylinder heads in my 92 V8 4.2 a bit over the specified to
    > try and stop the ever-so-leaking right cylinder head...
    > 
    > Could I try to turn the bolts 1/8 of a turn? 1/4?






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