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1961 cadillac conversion

Posted: Fri Jul 03, 2020 1:30 pm
by cadillac matt
i am building a 61 caddy coupe deville.
car has an ls swap with a sanden sd5h11 compressor.
i had a evap core made by old air products to replace the original and accept a orifice tube and a accumulator w/cycling switch.
i installed a 16 x 24 parallel flow condensor.
all the ducts and air doors are working as they should.
the evap case is sealed and there is no leakage around the core.
charged with about 30 ozs of r134a and the oil in the comp plus about 2 more ozs of pag 100
the problem:
comp runs, builds psi, cools the core, but i can only get about a 20* temp drop in the cabin air.
it runs 150 psi on the high side and 25 on the low. at idle, cooling fan on, doors closed, fan set on high in the recirc posistion.
i am not able to try at higher rpm due to dbw throttle and no helper. doesn't cool any better driving anyways.
any ideas?

Re: 1961 cadillac conversion

Posted: Fri Jul 03, 2020 2:57 pm
by Dougflas
Need to increase rpm to 1500. Sounds like low on refrigerant. In and out of evap should be same temp, then add a few more oz. You're going to have to play with the charge. What is ambient temp? 150 psi high side appears low; see if you can get it higher by increasing rpm and more refrigerant.

Re: 1961 cadillac conversion

Posted: Fri Jul 03, 2020 5:33 pm
by cadillac matt
ambient temp has ranged from 80 to 90. always the same. at most, 20* drop. tried more ref, as much as 60 ozs. tried less. no luck.

Re: 1961 cadillac conversion

Posted: Fri Jul 03, 2020 5:35 pm
by cadillac matt
the only time the high side gets higher is if i turn the cooling fan off. then it will cycle the high psi fan switch between 250 and 200 ish.

Re: 1961 cadillac conversion

Posted: Fri Jul 03, 2020 5:47 pm
by bohica2xo
An Sd5H11 to cool a barge like that?

108cc's / rev compressor & 30 ounces of refrigerant sounds right for a Corolla.

The OEM A5 on that car was 210cc's / rev. Charge was 80 ounces of refrigerant.

My first choice for a GM compressor would be the V7 - should be mounts for that, Corvette through 2004 had them.

Otherwise a 10SF20 from a 5.3 Suburban with rear A/C would work too. I know there are mounts for that.

Re: 1961 cadillac conversion

Posted: Sat Jul 04, 2020 7:55 am
by cadillac matt
you really think the comp. is too small?
wouldn't the psi's be way too low?
i have to stay with a sanden.
what would you suggest?

Re: 1961 cadillac conversion

Posted: Sat Jul 04, 2020 10:12 am
by bohica2xo
I guess you are using aftermarket brackets for the compressor? Afraid of OEM brackets?

Re: 1961 cadillac conversion

Posted: Sun Jul 05, 2020 1:02 pm
by cadillac matt
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had to use the holley setup to clear everything and to ad a/c.

Re: 1961 cadillac conversion

Posted: Sun Jul 05, 2020 3:17 pm
by bohica2xo
Well, the biggest Sanden you will find is the SD7H15. It is a little bigger, but not a direct bolt up either:

http://www.sanden.com.sg/opencms/opencms/sites/default/Sanden/_configuration/Catelogue/Product.jsp?pid=1005

You could use an ear mount V7 and get variable displacement in the deal as well as a bigger compressor:

https://www.ackits.com/comp-v7-pv6-3273

Either way you will need to remake part of the bracket for the compressor. Not a huge fabrication job.

The V7 has about a 1k btu advantage over the 7H15 at 1000 rpm, and a 4k advantage at 3000 rpm.

Re: 1961 cadillac conversion

Posted: Sun Jul 05, 2020 5:13 pm
by Tim
The import version is also available. GM and Nippondenso option are a call item.

https://ackits.net/product/14-20446new/