Old style 5kq 'round' TB seized

Bares, Vittorio Vittorio.Bares at nuance.com
Wed May 28 12:54:33 PDT 2008

I guess the only way to determine if we are running too lean is to
measure the EGT's, and or have an air fuel mixture gauge. I'm picking
one of those up from 034.

Now one of the other indications we had of lean was some 'popping' and I
was told flame bursts (but I thought that was rich mixture that would do
that?). As well as a significant wooshing sound coming from the exhaust
- Again I was told this happens when the metal overheats and allows
pressure to escape.

Tihol - thanks for the suggestion regarding a heat shield - I'll look
into that, might not be a bad idea - and yes, plenty of water (salt from
Candian winter rally's)...

Vittorio -

-----Original Message-----
From: Cody Forbes [mailto:cody at 5000tq.com] 
Sent: Wednesday, May 28, 2008 10:09 AM
To: Bares, Vittorio; quattro at audifans.com
Subject: Re: RE : Old style 5kq 'round' TB seized

Bares, Vittorio wrote:

> What we are theorizing is potentially that severe heat from the turbo
> and the manifold might be contributing to the failures. We were
> running excessively lean to the point where the exhaust manifold was
> glowing red. We believe the lean issue was a combination of the bad
> bearing in the TB and a bad fuel pump setup.

The manifold (and turbine housing) glow red under normal 'hard' use no 
matter what the fueling situation is. That's just how it is with
the exhaust back pressure before the turbo makes the EGT's very hot.

-Cody Forbes
'87 5ktq - Fast.
'87 5ktq QLCC'd plus some
'86 5ktqCD
'86 5k
'86 5k 

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