Re: IML: '58 A/C further adventures

[Chris Hawkins <imperial1966@xxxxxxxxx>]

Two things could likely prevent adequate cooling,
given a good compressor and adequate charge.  First is
the EPR valve.  If the 58 compressor is like the 60,
the EPR valve is externally mounted on the compressor
itself.  It is a 1" thick cylinder with tubing at each
end connecting to the top and bottom of the
compressor.  This will definitely prevent R-134
working to full efficiency, since the valve is
calibrated for R-12.  35 lbs pressure on the low side
is really too high for serious cooling.  The EPR valve
is preventing pressure from getting down to an optimum
of 18-22lbs.  

The other item is the expansion valve.  This is where
all the cooling takes place.  If the expansion valve
is not operating properly, little cooling will occur. 
My 60 had a clogged valve. (There is a fine mesh
screen in front of the valve that can clog up.)
I cleaned my valve and my 1960's system worked
reasonably well, but still not icy cold.  

If the expansion valve is up to snuff, my bet is on
the EPR valve.  I removed it on my 66. (They were
mounted internally in the compressor from 1961 -on.)

Now my system runs so cold, a compressor cut-off
switch was needed that will cycle the compressor on
and off when the evaporator is close to freezing.

You might need to change to a 1961 and later
compressor, if you go the non-EPR vavle route.  The
good news is it should mount without modification,
since it is essentially the same compressor.  However,
you may need to modify the hose ends where they attach
to the compressor.

Chris H.

66 LeBaron


P.S.  A third possibility could be heater core bleed. 
You might try disconnecting the heater core and
running the A/C.  If it performs properly, then your
heater control valve isn't closing and is allowing the
heater core to heat the cooled air as it passes to the
passenger compartment.



--- Ernie Stepney <estepney@xxxxxxxxx> wrote:

> Took the car up to my shop today and dug out the r12
> guage set (needed
> because of the fittings left alone on the
> compressor) and found 175 psi
> on the high side and 35 psi on the low side, text
> book numbers. I loaded
> another ¾ pound 134a in and it cools a little
> better, but still no
> screamin? hell. I don?t know if the ?58 compressor
> has that epr valve or
> not, ?59 service pamphlet mentions it ?58 doesn?t.
> Thanks for the advice
> so far, don?t be afraid to chime in with your two
> cents worth.
>  
> Ernie
>  
> -----Original Message-----
> From: mailing-list-owner@xxxxxxxxxxxxxxxx
> [mailto:mailing-list-owner@xxxxxxxxxxxxxxxx] On
> Behalf Of Ernie Stepney
> Sent: Friday, July 14, 2006 10:15 PM
> To: mailing-list@xxxxxxxxxxxxxxxx
> Subject: IML: '58 A/C
>  
> Hi Gang:
> Has anyone any experience with 134a in these units? 
> I replaced all the
> hoses, pressure and flow tested the evaporator and
> condenser, replaced
> the receiver dryer and expansion valve with R134a
> compatible parts. The
> cooling is poor even though the line from the
> expansion valve to the
> evaporator is cold. Here?s the kicker, the
> compressor is so cold that
> water is condensing on it. 
> Being a modern G* tech I?m used to the compressor
> running hot as it
> compresses the gas, am I missing something?
> Oh yeah the compressor is capable of over 300 psi on
> the high side with
> the service valve accidentally left closed, oops. 
> The sump is filled
> with mineral oil to the correct level and I put 6
> oz. of ester oil in
> the gas side. I charged it with enough refrigerant
> to clear the sight
> glass, like old For*s.
> Any ideas on this?
>  
> Ernie and The Black Bitc_!!
> 


__________________________________________________
Do You Yahoo!?
Tired of spam?  Yahoo! Mail has the best spam protection around 
http://mail.yahoo.com 


-----------------  http://www.imperialclub.com  -----------------
This message was sent to you by the Imperial Mailing List. Please 
reply to mailing-list@xxxxxxxxxxxxxxxx and your response will be 
shared with everyone. Private messages (and attachments) for the
Administrators should be sent to webmaster@xxxxxxxxxxxxxxxx
To UN-SUBSCRIBE, go to http://imperialclub.com/unsubscribe.htm