Date:         Tue, 10 Jul 2001 16:08:11 -0400
Reply-To:     72510.1173@COMPUSERVE.COM
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Helen Fahy <72510.1173@COMPUSERVE.COM>
Subject:      Re: Reducing exhaust heat extends the life of water hoses.
Comments: To: Wolfvan88@AOL.COM
Content-Type: text/plain; charset="iso-8859-1"

Some ANECDOTAL information, not engineering data, on a sample set of:

1 '74 911S with Stainless Steel headers w/wrap for 12 years(very limited
mileage no winter mileage),

2 '87 Westy with mild steel exhaust systems(2), 1 w and 1 wo wrap(5 to 8k
miles/yr, none in winter, it is on Wheelskates(tm) along with the 911 and
the M5, pushed off to the side in the garage waiting for spring).
My winter transportation- Ford 150 I6 4x4(a miserable gutless wonder), the
next one will be a Dodge w/turbo Cummins diesel.

I have wrapped a SS exhaust systems and have had no problems on the  '74
911S.  On mild steel exhaust systems, like on my '87 Westy, I have had
severe corrosion of the exhaust system ONCE, only where the wrap was in
use(driver side forward cylinder back over collector to cat and a small
section from passenger rear cylinder to collector).  The failed areas lasted
less than 3 years.  When the wrap was removed, the corrosion was not like
common rusting with flaking and such.  It was as though the metal had been
burned through, leaving a mass of very brittle crystalline steel chunks held
together by the unaffected new looking fiber wrap.

On the '87 Westy I have since used reflective fireshield, aluminum faced
fiberglass in a tubular format usually found in the same area of the speed
shop as the exhaust wrap products, to protect my oil pressure gauge sensor
line from exhaust heat.  Protecting this oil line was my sole motivation for
using the wrap in the first place.  The unwrapped system has now been on for
4 years, with only the common surface rust with no signs of the failure I
had with the wrap in place.

There are no doubt many factors at work in the failure of my only mild steel
system using a wrap.  I still like the idea of keeping the exhaust gases hot
and therefore the exhaust velocities high for better cylinder exhaust
scavenging, with a side benefit of reduced uncontrolled radiated heat within
the engine compartment.  But with the colossal PITA of replacing it, not
again for me.

Maybe a list metallurgist can definitively say whether mild steel is not up
to the task with a wrap or that I am full of it.

Joe


----- Original Message -----
From: "Robert Lilley" <Wolfvan88@AOL.COM>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Tuesday, July 10, 2001 9:58 AM
Subject: Reducing exhaust heat extends the life of water hoses.


>
> Extend the life of your water hoses by wrapping the exhaust pipes with a
heat
> retaining barrier.
>
> To reduce engine compartment temps, you can wrap the exhaust pipes with
the
> exhaust wrap from Gene Berg Enterprises and wrap the pipes and muffler.
This
> will reduce the engine compartment temps.
>
> http://www.geneberg.com/
>
> http://www.geneberg.com/exhaustpg16.htm
>
> Exhaust Wrap
>
> GB 900W This exhaust wrap is 2" wide and 50&#8217; long. This wrap
controls
> heat in the exhaust pipes. Also reduces chance of burns and protects hose
> from premature failure.
>
>
> Robert
>
>