[s-cars] S6 pinging woes - the continuation

[Bares, Vittorio]

Guides are also on the way to the machine shop - just in case they need
changing. They tell me that the head has to be heated and the guides
have to be 'driven' out and replaced while the head is still hot...

 

I figure I've got another 80k miles of fun ahead of me before I have to
do this again then ;)

 

Vittorio -

________________________________

From: djdawson2 at aol.com [mailto:djdawson2 at aol.com] 
Sent: Friday, August 14, 2009 3:21 PM
To: Bares, Vittorio; t44tqtro at gmail.com; s-car-list at audifans.com
Subject: Re: [s-cars] S6 pinging woes - the continuation

 

If you're going to have the head rebuilt, replace at least your exhaust
guides.  They wear the worst, and cost relatively little to replace.

At 235k miles, yes, there will be some piston/cylinder wall "clearance."

I think the head gasket is bound to fail sooner or later in high boost
applications.  I just think that between 4 and 5 is the weakest link.

Dave

 

 

-----Original Message-----
From: Bares, Vittorio <Vittorio.Bares at nuance.com>
To: djdawson2 at aol.com; t44tqtro at gmail.com; s-car-list at audifans.com
Sent: Fri, Aug 14, 2009 1:06 pm
Subject: RE: [s-cars] S6 pinging woes - the continuation

Nice!

 

I'm having the head decked, valves re-seated, and new seals - that way
the machine shop will be able to look at it and see if there's anything
worse going on...

 

ARP Studs will be here on Monday. Gaskets ordered today.

 

Everything I've read so far says that I5 piston slop is normal as hot
dogs and apple pie in America...

 

Emery cloth sounds good - I've also heard that a sharpening stone is
another way to go?

 

So the failure is due to excess heat - thereby *melting* the HG?

 

Vittorio -

________________________________

From: djdawson2 at aol.com [mailto:djdawson2 at aol.com
<mailto:djdawson2 at aol.com?> ] 
Sent: Friday, August 14, 2009 2:53 PM
To: Bares, Vittorio; t44tqtro at gmail.com; s-car-list at audifans.com
Subject: Re: [s-cars] S6 pinging woes - the continuation

 

1) Your block should be fine.  Spend some time getting the surface of
the block cleaned up... emery cloth will do fine.  You shouldn't find
any actual metal damage on the surface of the block.



2) Clean your head up as well.  However, there is a very good chance you
will find metal damage on the head.  If you can catch your fingernail in
the burn mark, get it welded up and then resurfaced.

3) Your pistons look good.  Based on the pic, it doesn't look like #5
got hurt at all.  This is very good news.  Forget about the
piston/cylinder slop... unless you intend to consider rebuilding the
bottom end.  If the engine performed well prior to this failure, it will
be fine after you repair it.

Why this happens?  I couldn't state any facts, but would speculate that
it is a combination of high boost along with the Audi I-5 engine's
tendency to build more heat at the firewall (#5) end of the engine.

Good luck with the repairs.  Oh... and consider using ARP studs on your
head (this is a test to see if QSHIPQ=2 0is reading).

Dave