[DeTomaso] A/C Question

Wed Sep 6 02:39:23 EDT 2006

Don,
     I believe the compressor was empty.  While driving around yesterday in 
80-85 degree weather,  the best I could achieve was about 50 degree air 
coming from the vents.  After the sun went down,  I could get 45 degree air 
from the vents.  I saw the temperature chart from ackits.com and it looked 
like my numbers were pretty close.  It seems that I have heard of guys 
getting lower temps than I got?
Thanks for your help,
Art
----- Original Message ----- 
From: "Don Thomas" <dt at ieee.org>
To: "Art Stephens" <artstephens at charter.net>
Cc: <detomaso at realbig.com>
Sent: Monday, September 04, 2006 5:30 PM
Subject: Re: [DeTomaso] A/C Question


>
> Art,
>
> I was just looking at my Mastercool Automotive Air Conditioning Basic 
> Service Manual.  From what the manual says, you are pretty close to what 
> you should expect in high and low pressures for a 134a system.
>
> But when I check further... the manual says that the compressor (Sankyo / 
> Sanden 5 and 7 cylinder)  should have 7-8 oz of oil in it, and that you 
> should only add ONE additional ounce of oil per component that you replace 
> (i.e. Condenser, dryer) and 3 additional ounces if you replace the 
> evaporator.  So if you only replaced the dryer and the condenser, you 
> should have 10 ounces total in the system.
>
> It sounds like you might have added a bit more oil than needed... but if 
> it's cooling good, I would just leave it alone.  Do you know how many 
> ounces of oil was already in the compressor before you added the 
> additional oil?
>
> Anyway, I would highly recommend this manual.  It goes over all the 
> different types of diagnostics and goes through them step by step 
> including converting a R12 system to a R134a system.
>
> The manual is available from ACKITS.NET.
>
> I hope that helps.
>
> -dt
>
>
>
> Art Stephens wrote:
>
>> Chris,
>>      I vacuumed the system for more than an hour at 27-28",  I couldn't 
>> get to 29".  I put in 8.5 ounces of PAG oil from a can with some 
>> refrigerant.  I have a Sankyo rotary compressor.  I used a new dryer and 
>> a new expansion valve.  Most of the system has been sitting open for 
>> better than five years.
>> Thank you,
>> Art
>>
>>   ----- Original Message -----
>>   From: Chris Difani
>>   To: Art Stephens
>>   Sent: Sunday, September 03, 2006 7:26 PM
>>   Subject: Re: [DeTomaso] A/C Question
>>
>>   Art:
>>
>>   How long did you evacuate the system for? 45 minutes after the gauge 
>> hit "28" or so? Or an hour? It sounds (diagnosing over email is even 
>> worse than over a phone) that the system has air in it. Or some kind of 
>> contaminate. Did you put the right amount of oil in the compressor? 10 
>> ounces or 12 ounces depending on the compressor.
>>
>>   But that sure sounds like a LOT of refrigerant for that system. 
>> Especially with that kind of gauge readings.
>>
>>   A lot of the AC guys do the evacuation for an hour, then they add the 
>> specified amount of refrigerant as per the factory spec's. Then add 
>> another half can or so, depending on what the thermometer is reading with 
>> the AC on, and fan on high. 134a is kind of notorious for not creating as 
>> much "cold" as 12 does in a system that was originally designed for 12. 
>> But if you've replaced the original York compressor with one of the 
>> rotary varieties, then you should be close to a 12 system, in terms of 
>> output "cool" and air flow.
>>
>>   But in any case, the key is the system evacuation, the replacement of 
>> the dryer (if it's been exposed to open atmosphere, or been in use for a 
>> few years), and then the installation of the factory recommended amount 
>> of refrigerant.
>>
>>   Not that I'm an expert, but that's what I've found in my studies, and 
>> the few systems that I've successfully recharged. The evacuation is 
>> ususally best done with one of the Robinair vacuum pumps that they make 
>> for the AC trade. The converted refrigerator compressors can work... but 
>> I've never seen them get the system "down" as far as a good commercial 
>> pump will.
>>
>>   Chris
>>
>>   Chris Difani
>>   '73 L #5829 "LITNNG"
>>   Sacramento, CA
>>   Email: cdifani at pacbell dot net
>>   Chris
>>
>>   ----- Original Message -----
>>   From: "Art Stephens" <artstephens at charter.net>
>>   To: <detomaso at realbig.com>
>>   Sent: Sunday, September 03, 2006 6:05 PM
>>   Subject: [DeTomaso] A/C Question
>>
>>   >     I have already added 75 ounces of 134 refrigerant to my newly 
>> converted system.  The gauges don't climb above 20 psi on the low side 
>> and 210 psi on the high side,  in 90 degree weather.  What gives?  My 
>> instructions say I should see higher numbers.  Do I just keep adding 
>> more?  At ten bucks a can,  I figured I better start asking some 
>> questions.  The air blows cold,  but I could stand colder.
>>   > Art
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