Re: HES

[Bill Moss <bill.moss@xxxxxxxxxxx>]

Mick wrote:
> At 10:55 PM 8/17/2006 -0400, Bill Moss wrote:
>
>> There is NO cracking, no discoloration and no obvious breaks. The clear
>> shrink over the splices is still clear and the black plastic wire
>> separator is still there and fine. The cable jacket (heat shrink) was
>> soft and pliable.
>
> Bill,
>   Sounds like your harness has not been affected by heat as
> badly as most of the ones I've seen.  Either that or you've never
> been stuck in traffic till your oil temp gauge reached the red zone. :)
I added a 60mm high volume 12v computer fan to the back of the air box.
I fabricated an aluminum adapter plate with a 40mm hole that fastens to
the box, and the fan fastens to the plate. This allows for a more rigid
mount. I simply turn the switch on when the RID hits six bars. In the
worst stop and go traffic in 90+F weather, the oil has never gone over 8
bars and has only hit 8 bars once since 1998. Note that synthetic oil
also helps here since it has better thermal conductivity than petroleum
based oils. Radio shack sells a decent fan but I get high volume ones
from Newark, Digikey, etc..
>
>
>> If this sounds good, than I'm going to reseal with Scotch #7 tape (self
>> sealing silicone, 250C rating), and maybe some Permatex black (232C
>> rating). Any other suggestions (please keep it on the subject) will be
>> appreciated.
>>
>> Question, since the Permatex black is rated for continuous duty above
>> 200C and is a terrific electrical insulator and a decent conductor of
>> heat, would it be a good idea to fill the cable with it prior to
>> sealing, so that it adds to the wire insulation and heat transfer to the
>> plate. Just a thought.
>
> I do think filling the cable with Ultra Black silicone sealant won't hurt
> and may even help.  Anything that protects those internal wires from
> heat and moisture will extend the life of your harness.
>
> Mick
> Tucson
>
Thanks for the input, you have been a real help. Theoretical knowledge
and even practical knowledge (mine) in other areas only helps me
understand what is happening here, not the actual cure.

Update:
I checked the diode switching curve for each of the Hall switches using
the timing box I built from plans on the Internet and my oscilloscope.

Set at 1 microsecond per cm and in storage mode, I switched each until I
had a good trapezoid on the screen. I did this 10 times for each switch.
The result was a smooth rise time (skew) and decay time of ~0.4
microseconds. Both were perfectly smooth. The upper and lower lines of
the trapezoid were parallel with the base line and there was no
detectable jitter at the transition points. I performed the same test at
a measured 140C and the results were the same.

Again, Thanks for the help.

- -- 
William (Bill) Moss
billmoss@xxxxxxx
  Those who will not reason,
  are bigots,
  those who cannot,
  are fools,
  and those who dare not,
  are slaves.
by Lord Byron
  God grants liberty only to those who love it,
  and are always ready to guard and defend it.
by Daniel Webster

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