[DeTomaso] use sight glass in AC that has been retrofitted to 134a?
JEFFREY COBB
jeffcobb1 at me.com
Fri Aug 5 06:37:25 EDT 2016
Jim,
All cars use different pressures and for examples this week we did a/c work on a 124 Fiat, many Benz-Bmws-Toyotas, a 71 e-type, Ford +Chevy trucks, a Cobra kit car and a Mangusta.
But basic pressures at 1,500 rpm with cooling fans on and on high, with both windows open, rear and front hatch closed, high fan and not on recirc should be about 35 + - low side and 250 + - high. Seems like a 7:1 ratio works the best. Converted systems do need different numbers but never too much of a change. So your low range should vary from 20 to 38 psi and the high 210 to 260 psi as long as above written parameters are meet. The proper pressures will equate to the coolest temps. You have to note that and remember you are just setting the vent output for the coolest temp not some pre-considered ideal temp you hope for.
About 30 % of all of our a/c fixes are fixing the stuck on heaters. We are in hot Louisiana, make sure your heater is truly shut off by doing a liquid test.
Do use the correct oil and add 2 oz if you are not sure of how much is in. You can always expel the working high side into a cloth or jug for 2 seconds to get an idea if you are oily enough. A lot of spit indicates fine but dry expelled gas needs oil.
Keep cool,
Jeff
Jeff Cobb- I pad
W-225-343-7525
C-225-907-4514
Jeff Cobb Auto Works
1316 S. Acadian Thruway
Baton Rouge, La.
70806
www.LiveOakConcours.org
On Aug 4, 2016, at 11:05 PM, Pantdino <pantdino at aol.com> wrote:
> Hi, Jeff,
>
> What should the pressures be?
>
> Thank you,
>
> Jim
>
>
> -----Original Message-----
> From: Jeff Cobb <jeffcobb1 at me.com>
> To: Pantdino <pantdino at aol.com>; detomaso <detomaso at detomasolist.com>
> Cc: Jeff Cobb <jeffcobb1 at me.com>
> Sent: Thu, Aug 4, 2016 6:55 pm
> Subject: Re: [DeTomaso] use sight glass in AC that has been retrofitted to 134a?
>
> The sight glass is always used as a reference point. You must go by the dual gauges.
> Never by the low side only.
>
> Jeff Cobb
>
> On Aug 4, 2016, at 8:44 PM, Pantdino via DeTomaso <detomaso at server.detomasolist.com> wrote:
>
> > After switching the AC system to 134a, do you use the sight glass in
> > the dryer or go by the pressure at the low pressure port like with
> > modern cars?
> >
> > Sorry, but I don't recall what I learned several years ago when I
> > switched the system over.
> >
> > Jim Oddie
> > _______________________________________________
> >
> >
> > Detomaso Email List is not managed by POCA
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> >
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>
-------------- next part --------------
Jim,
All cars use different pressures and for examples this week we did a/c
work on a 124 Fiat, many Benz-Bmws-Toyotas, a 71 e-type, Ford +Chevy
trucks, a Cobra kit car and a Mangusta.
But basic pressures at 1,500 rpm with cooling fans on and on high, with
both windows open, rear and front hatch closed, high fan and not on
recirc should be about 35 + - low side and 250 + - high. Seems like a
7:1 ratio works the best. Converted systems do need different numbers
but never too much of a change. So your low range should vary from 20
to 38 psi and the high 210 to 260 psi as long as above written
parameters are meet. The proper pressures will equate to the coolest
temps. You have to note that and remember you are just setting the vent
output for the coolest temp not some pre-considered ideal temp you hope
for.
About 30 % of all of our a/c fixes are fixing the stuck on heaters. We
are in hot Louisiana, make sure your heater is truly shut off by doing
a liquid test.
Do use the correct oil and add 2 oz if you are not sure of how much is
in. You can always expel the working high side into a cloth or jug for
2 seconds to get an idea if you are oily enough. A lot of spit
indicates fine but dry expelled gas needs oil.
Keep cool,
Jeff
Jeff Cobb- I pad
W-225-343-7525
C-225-907-4514
Jeff Cobb Auto Works
1316 S. Acadian Thruway
Baton Rouge, La.
70806
[1]www.LiveOakConcours.org
On Aug 4, 2016, at 11:05 PM, Pantdino <[2]pantdino at aol.com> wrote:
Hi, Jeff,
What should the pressures be?
Thank you,
Jim
-----Original Message-----
From: Jeff Cobb <[3]jeffcobb1 at me.com>
To: Pantdino <[4]pantdino at aol.com>; detomaso
<[5]detomaso at detomasolist.com>
Cc: Jeff Cobb <[6]jeffcobb1 at me.com>
Sent: Thu, Aug 4, 2016 6:55 pm
Subject: Re: [DeTomaso] use sight glass in AC that has been retrofitted
to 134a?
The sight glass is always used as a reference point. You must go by the
dual gauges.
Never by the low side only.
Jeff Cobb
On Aug 4, 2016, at 8:44 PM, Pantdino via DeTomaso
<[7]detomaso at server.detomasolist.com> wrote:
> After switching the AC system to 134a, do you use the sight glass in
> the dryer or go by the pressure at the low pressure port like with
> modern cars?
>
> Sorry, but I don't recall what I learned several years ago when I
> switched the system over.
>
> Jim Oddie
> _______________________________________________
>
>
> Detomaso Email List is not managed by POCA
> Posted emails must not exceed 1.5 Megabytes
> DeTomaso mailing list
> [8]DeTomaso at server.detomasolist.com
> [9]http://server.detomasolist.com/mailman/listinfo/detomaso
>
> To manage your subscription (change email address, unsubscribe, etc.)
use the links above.
>
> Members who post to this list grant license to the list to forward
any message posted here to all past, current, or future members of the
list. They also grant the list owner permission to maintain an archive
or approve the archiving of list messages.
References
1. http://www.LiveOakConcours.org/
2. mailto:pantdino at aol.com
3. mailto:jeffcobb1 at me.com
4. mailto:pantdino at aol.com
5. mailto:detomaso at detomasolist.com
6. mailto:jeffcobb1 at me.com
7. mailto:detomaso at server.detomasolist.com
8. mailto:DeTomaso at server.detomasolist.com
9. http://server.detomasolist.com/mailman/listinfo/detomaso
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