1961 cadillac conversion

Friendly format provided to inquire about automotive a/c systems.
Archived Forum

Moderators: bohica2xo, Tim, JohnHere, Dougflas, HECAT

Al9
Posts: 223
Joined: Tue Mar 10, 2020 3:26 am
Location: Southern Europe

Re: 1961 cadillac conversion

Postby Al9 » Wed Jul 08, 2020 12:40 am

Just make sure to have a binary/trinary pressure switch somewhere on the high side that turns the clutch off once the pressure gets too low. That way the compressor will be spared in case the system suddenly loses a large amount of refrigerant for whatever reason.

Prolonged operation with low refrigerant levels, even if the compressor doesn't seize up, might create considerable amounts of wear (i.e. increased piston blow-by, eventually getting to the point that the variable displacement mechanism is no longer able to regulate piston stroke correctly resulting in a weaker and noisier compressor).
User avatar
bohica2xo
Posts: 831
Joined: Wed May 11, 2016 4:12 pm
Location: Las Vegas, NV

Re: 1961 cadillac conversion

Postby bohica2xo » Mon Jul 13, 2020 10:01 pm

Is that the Holley 20-131 compressor bracket you are using?
cadillac matt
Posts: 20
Joined: Fri Jul 03, 2020 1:18 pm

Re: 1961 cadillac conversion

Postby cadillac matt » Tue Jul 14, 2020 3:03 pm

i'm using the 20-132 bracket set for the sanden comp. i can get just the comp. bracket for the r4 if needed. i'm leary of using a r4 comp. they have a bad rep.
User avatar
bohica2xo
Posts: 831
Joined: Wed May 11, 2016 4:12 pm
Location: Las Vegas, NV

Re: 1961 cadillac conversion

Postby bohica2xo » Tue Jul 14, 2020 4:40 pm

The R4 would go 80,000+ miles around here in a Suburban with dual A/C running limo duty.

What seemed to kill them was either running them with a low charge, or exterior corrosion.

Cheap remans from sketchy sellers made them sound worse than they really were. Add to that the learning curve - in 1995 we were just starting to see serpentine and parallel flow condensers. People were still trying to flush those condensers after a compressor failure. Not realizing the condenser was the primary filter.

Around the same time we heard a lot of talk about Ford compressors & "black death". Axial piston FS10 style compressors failing for "no reason" leaving black goo in the system. Lubrication failures with polymer piston rings and SEC PAG. Lots of learning went on in the early 90's with 134a, condenser & lube changes.

Todays lubricants, better manufacturing tolerances than ever before - and a better understanding of the refrigerant system requirements would make a new R4 an acceptable compressor. It has enough volume for your needs, it is a direct bolt on & is compatible with your existing CCOT system. Your only problem with your system right now is a lack of pumping capacity. An R4 is the most direct bolt on solution.

Use the standard piston R4 with the small diameter serpentine clutch (Ex. 1995 Suburban application) and avoid the "scroll replacement" - china slapped a small scroll in an R4 can and they have a really poor reputation around here.
Al9
Posts: 223
Joined: Tue Mar 10, 2020 3:26 am
Location: Southern Europe

Re: 1961 cadillac conversion

Postby Al9 » Wed Jul 15, 2020 2:22 am

That PAG 150 is surely going to get really thick inside a cold evaporator. Maybe that's what aggravates oil return issues with low charge.
User avatar
bohica2xo
Posts: 831
Joined: Wed May 11, 2016 4:12 pm
Location: Las Vegas, NV

Re: 1961 cadillac conversion

Postby bohica2xo » Wed Jul 15, 2020 8:30 am

Again, the R4 does not do well running on a low charge - but neither does ANY other compressor.

The SEC PAG oils of the 1990's were garbage. We ran BVA POE 100 in all of the R4 compressors without any issues. Idling for hours in the 110f heat.

.
cadillac matt
Posts: 20
Joined: Fri Jul 03, 2020 1:18 pm

Re: 1961 cadillac conversion

Postby cadillac matt » Wed Jul 15, 2020 9:09 am

wow. more good info. thanks again! what would be a good brand for a new r4?
User avatar
bohica2xo
Posts: 831
Joined: Wed May 11, 2016 4:12 pm
Location: Las Vegas, NV

Re: 1961 cadillac conversion

Postby bohica2xo » Wed Jul 15, 2020 2:24 pm

I have not bought a new R4 for a few years. Contact Tim, he will know which supplier has their act together. I buy compressors from him.

Use whatever oil the compressor manufacturer recommends. If it is PAG, make sure it is the DEC variety.

.
cadillac matt
Posts: 20
Joined: Fri Jul 03, 2020 1:18 pm

Re: 1961 cadillac conversion

Postby cadillac matt » Wed Jul 15, 2020 4:12 pm

thanks again.
User avatar
Tim
Site Admin
Posts: 499
Joined: Tue Apr 12, 2016 2:19 pm
Location: Scottsdale, Arizona
Contact:

Re: 1961 cadillac conversion

Postby Tim » Wed Jul 15, 2020 4:30 pm

Original GM R4. Still not the quietest compressor out there. So take notice before ordering.

https://ackits.net/product/14-20189/
------------------------------
Please support ACKITS.com for your Auto A/C Parts and Tool needs.
P:602-233-0090

Return to “Automotive Air Conditioning Forum”