RE: Possible 5kcst Blown Head Gasket Woes

["Ned Ritchie" <NED@IntendedAcceleration.com>]

Doug,

I'm sorry this happened to you.  From my experience is appears to be a turbo
that has seen too high revs for a given boost.

When the stock K26 turbo, a K26-2664 GA 6.95, exceeds the rpm limits shown
on the compressor map the impeller will oscillate violently and destroy the
bearings and seals in about 4 seconds.  You're fortunate you do not own an
A4 1.8 turbo.  It will do it in only 2 seconds.

The rpm limits are limits that vary given the "boost pressure divided by the
intake pressure".  This is called the "pressure ratio."  It is especially
important at high altitude as the ratio gets a larger value.  If boost
pressure is too high even at a low engine rpm it's bye bye turbo.

Worst case is you developed a hole in the wastegate diaphragm.  This allowed
boost, which could not be controlled by your modified computer.  This
damaged the turbo as no safeties were in place in the computer and possibly
blowing the "cylinder head gasket" round holes into pears shaped holes.
But, my gut feel is only the turbo is gone.

Early on in my R & D I had a few turbos go bye bye too!  One new turbo
lasted only 1 mile, and was not warranted by folks at KKK.  Last month I
blew out a stock K24 on my wife's 91 200 at about 26 psi in one burst of
power in 3rd gear (about 4 seconds)  Now I know at least the limit on that
turbo.  The special turbos that I import now have tighter tolerances and
better balancing.  They last longer.

If you drive the car to any quality shop they can check for hydrocarbons in
the radiator fill tank.  If there is none.  It is probably only the turbo.

Give me a call.  I may have a used K26 turbo around somewhere.

Ned Ritchie
http://www.intendedacceleration.com/
(360) 754-1411




-----Original Message-----

Date:	Sat, 20 Jun 1998 09:23:18 -0500
From:	"Douglas Hurst Quebbeman" <dougq@iglou.com>
Subject: Possible 5kcst Blown Head Gasket Woes

Oh, woe unto me! Please helpme, fellow Q_Listers!
Thick clouds of white smoke out the tailpipe. I've
been here before, and I don't like it.

Before I spend money I don't have, what can I do to
make certain of my diagnosis?

One other data point: there is some smoke around the
exhaust manifold, too, but it's not coming out under
pressure, it's more like fumes just wafting up off the
EM. Would oil be escaping through a blown MC engine
head gasket?

Lastly: any estimates on cost to repair?
Thanks in advance for all BTDTs, YMMVs, and Told-You-Sos.
:-(    :-(     :-(     :-(     :-(     :-(     :-(     :-(
- --
* Douglas Hurst Quebbeman (dougq@iglou.com)       [Call me "Doug"]
    QuattroClub USA# 4536     Audi International # 100024
       74 100LS Auto,     84 Coupe GT
       77 100LS Auto,     86 5Kcstq QLCC 1.8bar
"The large print giveth, and the small print taketh away."  -Tom Waits