Underhood temperatures

[Garfield Willis]

On Fri, 26 May 2000 08:13:00 -0700, "John Dammeyer"
<johnd at autoartisans.com> wrote:

>I quite agree that 4" is way too close.  We didn't mount them or tell them where to mount
>the box.

Oh, I see. Oh well, sounds like their bad choice may have forced the
issue tho, and helped motivate them to put it in the cabin where it
belongs.

>But when we looked at it before running the installation it just didn't click.
>In hindsight,  I must have just seen the heat radiate sideways from the block and header
>and not forward.  Silly really.  As soon as I felt the box and looked at the position the
>lightbulb went on.  The difficult part was convincing the customer that the box was in a
>poor position.  Ultimately,  the boxes were moved inside the cabin of the craft out of the
>salt water spray and harsh outdoor environment.  After that the injection problems were
>things like silicone, filings and teflon tape in the fuel supply which would block the
>fuel and cause spark plug and valve burning.  (Of course that was the boxes fault).  The
>customer did not practice 'clean room' techniques while building the fuel system.  One of
>the service guys cut apart a RACCOR fuel filter that had been cleaned and flushed and it
>was filled solid with RTV bits and metal filings.  Then they opened up the tank and found
>even more crap.  We think some of the lean conditions were due to the pump inlet being
>blocked up.

I know this is true when building aircraft, and I can't imagine
custom-built cars and other vehicles being any different, but it is
considered an unavoidable truism, that NO MATTER how careful and clean
you try to be, you'll still be hauling trash outta your fuel system for
the first 25hrs, whether it's an all-aluminum construction (in which
case you get metal filings and sealants) or a composite job (in which
case you'll get bits of foam, glass, resin, you name it). Especially if
you're also building the tank.

Course it only gets worse if extreme care isn't taken all along the way.
That's why amongst experimental aircraft builders, it's considered SOP
to remove & replace the fuel filters VERY often during the bring-up, and
just EXPECT these kinds of things to happen. Because they do almost
every time.

BTW, one last thing, teflon tape is NEVER used on aircraft fuel
plumbing. Just NEVER, for the very reason you cite above.

Gar


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