Re: [ihc] A/C and wiring

["John Stricker" <jstricke@xxxxxxxxx>]

Ryan,

Crack the books again, it's not SILICONE, it's SILICA.  Different stuff.

When they first started doing conversions it was thought that all hoses,
o-rings, etc., would have to be replaced.  As time went on, it was found
that hoses that were serviceable with R12 sealed themselves over their
lifetime with the old refrigerant oil and they work as well, if not better,
than new hoses.

You may be going to school for it, I've converted maybe 60 or 70 vehicles
and I'll stand by my real world experience over what the books say (which,
btw, in the automotive world they do NOT recommend replacing the hoses
anymore unless they're damaged, and haven't for at least 6 or 7 years in the
schools that *I'VE* been to for automotive A/C work).

Aircraft maintenance and repair is a whole other ball of wax because of the
regulatory issues involved.  If the FAA or the manufacturer mandates that
all hoses be changed, then by GOD they WILL be changed, if it's a good thing
or not!  8-)

You're learning as much regulatory compliance in class as you are mechanics
and they don't transfer well into the real world sometimes.

I wasn't talking about the seals wearing out in the York/Tecumseh, I was
talking about the piece of crap locking up a rod or having some other
catastrophic failure.

The York/Tecumseh is a reciprocating compressor, just like a small engine.
It was not designed (back in the times that IH used them) for the oils that
are required now for R134.  They also were not designed for the higher
pressures that R134 operates at.  Both of those things shorten the life of a
device that was never all that reliable (or smooth in operation) to begin
with.  Both the oil change and the higher pressure makes the compressors run
hotter and changes the clearances in them.  Test the theory out sometime by
putting a infrared pyrometer on the case of one before and after a 134
conversion.  I have, when I wanted to find out why the Tecumseh's wouldn't
last after conversion to 134.  I may even have an old case or two laying
around here with a ventilation hole in the side after the rod snapped.

I don't have a problem in the world with someone converting a York/Tecumseh
over to R134.  Just don't waste time and money resealing something that's an
antiquated design to begin with.  Put a new receiver drier on it, change the
oil, load it with 134 and be happy as long as it works.  In a couple of
years when the compressor shells out, then do the upgrade to a modern
compressor.

John Stricker

----- Original Message ----- 
From: "Ryan Moore" <baradium@domain.elided>
To: "John Stricker" <jstricke@domain.elided>; "IHC Digest"
<ihc-digest@domain.elided>
Sent: Monday, May 24, 2004 9:54 PM
Subject: Re: [ihc] A/C and wiring


>
> ----- Original Message ----- 
> From: "John Stricker" <jstricke@domain.elided>
> To: "IHC Digest" <ihc-digest@domain.elided>
> Sent: Monday, May 24, 2004 16:45
> Subject: Re: [ihc] A/C and wiring
>
>
> > Actually, a far better solution is to use the York/Tecumseh compressor
for
> > it's true purpose, that of a boat anchor, and replacing it with a
> > Sanden/Sankyo unit that will run smoother, take less power, and last at
> > least 4 times longer without a leak.
> >
> > I have a write-up for putting it on a Scout on the BB and virtually all
> the
> > steps should be the same since they go on the same engine as the
Travelall
> > and they are, for all intents and purposes, the same design system.
> >
> > You need to replace the receiver/drier and it has desiccant in it, not
> > silicone.  It needs to be replaced due to age and contaminants over the
> > years.  Since the system is an expansion valve type system, it will work
> > fine with 134 or R12 without any other changes.  You don't need to
replace
> > your hoses unless you suspect they're damaged or leaking in some way,
> > they'll work fine with R134.
> >
>
> Don't agree with that.  We studied in depth conversions between the
systems
> in my aerospace systems class (piston a/c still use freon, with many older
> ones using R-12, of course a change in an aircraft requires an STC and is
> big $$$ anyway).   Anyway, hoses that didn't leak with R12 may leak with
> R-134a.   BTW, IIRC the dessiccant is made with silicone...
>
> > Use one of the new oils that are multi-purpose and you'll be fine.
> >
> > If you stick with the York/Tecumseh style compressor and go to R134 and
> it's
> > compatible oil, don't expect the compressor to last more than a year or
> two
> > as the units aren't really designed to work properly with that oil and
> > won't, at least for long.
> >
> > John Stricker
>
> If you actually get new seals put in they'll last as long as in their
> original R-12 applications.  Another thing about the rubber parts all
> needing to be replaced.  Most people don't get the seals redone so they
may
> start leaking.  The units will work fine with R134a if you get the
> appropriate seals put in.  It's nothing to do with design, it's simply the
> seals.
>
> Aircraft use both types of compressors btw.   I don't know if it'd be cost
> effective to get the York rebuilt rather than simply buy a sanden, but a
> sanden isn't your only option.
>
> -Ryan
>
>
>
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