Updating a '72 Ford Gran Torino

eliteman76 on Wed July 23, 2014 11:49 AM

Year: 1972
Make: Ford
Model: Gran Torino Sport
Engine Size: 351C
Refrigerant Type: R134a
Ambient Temp: 79
Country of Origin: United States

Good Morning-

I'll try to stay on topic and want too much.

My post consists of the following issues:
-I replaced the STV with a POA eliminator kit for clutch cycling - mistake? See below for details.
-Compressor oil level versus original oil level for my vehicle.
-Ideal system pressures and R134a charge amount.

A lot of good information here on the forum, and spent two very late nights sifting through retrofits, POA/STV posts.

I need to get my low and high side readings when I get home tonight, I can't find my notes from last night. I was out there until 330AM reading manuals trying to calculate if I have things correct and called it a night.

Reason for posting:
In 2011, I had retrofitted my 1972 Ford Gran Torino. I rebuilt the system using OEM specific parts for use with R134a.

That had consisted of:
-A know original, tested and functional 1971 dated factory York compressor
-A good original Ford factory condenser
-Original STV valve {not adjusted}
-Original Evap assembly on firewall
-Hoses rebuilt with Goodyear barrier hose, I elected to keep the R12 fittings as my gauge set has 134A adapters but it unscrewed fit R12 ports.
-Replacement dryer for OEM, for R134a
-Replacement expansion valve

R12 charge calls 4 lbs 8 oz
Oil charge is questionable here, the Ford service books are vague. I was reading again in my factory manual there was no specification listed for the oil a York would take.
At the time of the first retrofit I had a local HVAC guy assisting me on the vacuum and recharging as he had the correct tools.

My background I spent 7 years as an autobody tech and did a number of AC repairs on late models. Not much in the way of trouble shooting, more of just pull a frame/unibody, rebuilt the car/truck, replace the coolers, line and related, and evac and recharge. I by no means am a master tech, and I never was certified for R12 like I should have been considering the stuff I was rebuilding. {I did however try to avoid caveman, vent to the atmosphere stuff}

2011:
After dialing in the system, we found it took the York happiest with six 12 oz cans + oil charge of 10 oz oil for the system from what we measured at the time. {This would seem to be overcharged?}
According to the formula of reducing to 90% of the R12 charge then reducing another -.25 LB {4 oz} I was figuring it should have been like 5 cans, 12 OZ size, plus a shot off a sixth. I found at that time, dialed in with summer temps around 85F I had 18PSI on the low side.
I do not recall the high side pressures but I want to say it was in the normal spec of 2.5x temp when the system was topped off and running. 220PSI? I really with I could find my notes from then.

I ran my car in this configuration since 2011 to early 2014 with mixed results. At times it would be absolutely frigid. Other times, like on the interstate at speed {car is currently geared for highway driving, RPM's spinning around 3,000-3,500 RPM.
At that time, the Ford service book for the HVAC section, R12 pressures 10-20 low side, and 200-220 from what I recall seeing last night. Over 300 PSI getting to 340-350 according to the book would indicate malfunction and to shut down the system immediately.
I realize the GTS has a greenhouse equal to the Chrysler building.

Now this brings me to my reason for posting. I elected to swap brackets on my car to clean up the engine bay with factory brackets powder coated to clean up things.
When I pulled the idler tensioner pulley bracket I had mounted to the York, one of the bolts had in my 2011 install bottomed out just enough to crack the very bottom of the bolt boss on the right front of the compressor. it remained charged, until I backed off the bolt. It had a slow leak, spooked the hell out of me, so I cranked it back down. it stopped the leaking, but at this point I am SOL and JWF. I elected to open the garage up, turn a fan on, and then the York gave up the ghost and decided to let go on me as I wasn't able to get a machine on it in time to pull it down. The crack was at the very bottom, and the end of the bolt managed to be the perfect length to compress it against the case.

That started me on my search for updating my car to modern parts for R134a. After discussions with the local shop that rebuilt my hoses, and two suppliers, one being the ACKITS.com guys who put up with me calling 3-4 times with condenser questions, I dealt with my local shop and picked up the following:

That had consisted of:
-New Sanden compressor 709 Vintage air part#04709-VUA.
-New Parallel flow condenser. Core size is 28" long x 18" tall, as I wanted to match the original fin and tube Ford unit for size, and the shop's suggestion to go as large as possible.
-I went with a POA eliminator kit specific for my car at the suggestion of the shop, with the pressure switch, more as a safety suggestion by the shop.
-Original Evap assembly on firewall
-Reused hoses rebuilt with Goodyear barrier hose, some new fittings crimped on for use with the sanden unit. One fitting is a #12 to #10 fitting to adapt to the #10 port on the 709. all others remain OEM size.
-Replacement dryer for OEM, for 134A. {In this case I have had two lines made to keep the install in a similar install to the factory location, with the exception of placement on the opposite side of the condenser due to the output of the #6 port. I placed it in the same relative location and layout.
-Replacement expansion valve.
-Installed the Vintage Air 351c specific Sanden adapter bracket with idler.
-Installed Heavy duty service V belt

I still have the STV valve {not adjusted}. I am beginning to wonder if it was a mistake to have gone to the POA eliminator kit versus calibrating the STV valve.

Last night, 79ÃÂ°F ambient temp, 70-75% humidity, I elected to do one last check and charge the system.
I purchase a 6CFM vacuum pump, and was at -30 IN Hg, and it held the vacuum overnight with no changes. I did draw vacuum twice on the system as a precaution due to {recommended solvent flushing out the system due to me being paranoid my previous install and reusing older components.

The 709 came with a 135CC/5oz oil charge. Vintage air stated that oil charge was sufficient for my system. The local AC shop agreed.

I have questioned this, as I back flushed the hoses and evap, and the rest of the system was new. I added a single PAG46 charge can, 3 oz, but after the charge, it was only 1 additional oz of oil.
Questioning if this should be increased to 8-10 OZ per the original system.

R134a used was Dupont brand with no oil added. 12oz cans.
I also added one small bottle, 1 oz of the "Ice synthetic temp booster", and leak dye, into one hose before sealing the system.

I used a can tap with hand trigger on the evap service port fitting, with my gauges hooked up. First can went in with the car off.

I rotated the compressor by hand 15-20 times before starting.

I then started my car, it was idling at 1200rpm in neutral. I turned the AC on, and added 4 more cans. System pressures didn't seem out of line {sorry I didn't write them down, I will check again tonight and post back}.

The compressor clutch was cycling, running good, no noises, no belt slip, I was truly happy {that york slipped over 3500-4,000 RPM, and with a four speed car drove me INSANE}.
I need to find my good thermometers as I dropped the one I was using and well, stepped on the thing.

With the car idling, I got in and increased the RPM to 1500. It cooled down while the compressor was running, quite nice. The the unit would shut off, and I'd get luke warm air.
I took the car for a drive, and it was cycling cool warm cool warm. Not exactly the ice I was expecting.
My Edelbrock carb is missing the idle solenoid to bump the RPM up to 1500 RPM when the AC kicks on, waiting for that to get here to install.

The blend doors and heater core shutoff valve are functioning and removed from potential issues.
I did not try spraying water on the condenser as some suggested on other posts.

I'm looking for guidance here with out having a mental breakdown.

Biggest issue is we are taking a 2,000 mile road trip in the next week for a major show and the wife and I need the AC functioning.
I don't want to, but if I have to crack the system open, swap back the STV, and recharge, so be it.

I'm under the gun to get this pieced back together and operating properly.

I'm also with the Fairlane Club of America and on a number of the Torino specific sites, and I would like to really have this cleared up, so I can help others avoid the pitfalls in retrofitting their cars.

Dougflas on Wed July 23, 2014 12:51 PM

That started me on my search for updating my car to modern parts for R134a. After discussions with the local shop that rebuilt my hoses, and two suppliers, one being the ACKITS.com guys who put up with me calling 3-4 times with condenser questions, I dealt with my local shop and picked up the following

Why not buy your parts from ACKITS since they run this site and did help you???

Your old York's oil level was meant to be checked with a dip stick tool

I do not like POA eleiminator kits. If it were mine at this poinrt, I would have used the TXV and an eavporator sensing switch to cycle the compressor in order to cycle the compressor on temperature instead of pressure as the eliminator kit does. Your old York's suction pressure would be low in the 18 to 22psi range because the low side was directly on the compressor service valve. You're now playing refrigeration engineer so you'll need to play with the charge level. 80 to 85% of the R12 level is a starting point. ou want the compressor to cycle off before it can freeze up.

eliteman76 on Wed July 23, 2014 1:43 PM

I have been dealing with my local AC shop for a number of years, and had them build my hoses. They stocked the condenser and most of the fittings for my update, and have also helped me with other projects, so I wanted to keep my money local with a family run business that supports local car shows...not trying to disrespect the guys that run the forum.

I noticed the dip stick portion in the manual, but thought it was odd in the fact no specific level was stated. The other era Fords such as the Thunderbird used a 6 piston compressor {delco?} and there were specific charts for oil levels.

I called Classic Air on the POA and the gentleman I spoke with was adamant about the charge only being 3 lbs 4 oz; Old Air products {supplier for the POA eliminator} showed 4 lbs 4 oz for some cars, 4 lbs 8 oz for other Ford intermediates.

I re-verified with the local shop, and they suggested I verify at Idle if in fact I have 30-40 PSI on the low side, and 2.5x temp on the high side, blower set to low, and windows and doors open.

Hopefully I was correct on my original charge, and didn't overcharge the system.

Thanks for your advise on my issue...I really appreciate the help.
Andrew

eliteman76 on Wed July 23, 2014 10:22 PM

I rolled the car out, hooked up off the hi/low ports off the compressor.

Temperature: 79F
Humidity level has dropped considerably compared to last night.
At idle speed, I am running ~35-43 on the low side. Low side drops eventually down to ~25 before the compressor kicks off.
The high side creeps up, it's peeked near 300.
Engine RPM is roughly 1,000.

The instant I attempt to throttle up to 1500-200 RPM, high pressure rockets up, and I kill the ac as I don't want to kill the compressor by exceeding 340-350psi

I'm checking into have the shop pull the system down, and recharge with a machine this time...Suppose this is what I get for not using a scale with a single tank.

I can only make certain guesses to my error(s) at this point despite attempting to do this the correct method base on charge.

On the evap case it's cold. But not experiencing frosting issues.

alan73 on Thu July 24, 2014 7:19 AM

suspect your not getting good airflow through the condenser causing your high side pressure to be that high.

eliteman76 on Thu July 24, 2014 10:04 AM

Clutch fan is new with 7 blade heavy duty cooling fan.
Have not considered an electric fan however.
I neglected to spray water into the condenser last night. It felt slightly warm to the touch but not hot. Cooler on the bottom.

bohica2xo on Fri July 25, 2014 8:58 PM

Quote
Originally posted by: eliteman76
I have been dealing with my local AC shop for a number of years, and had them build my hoses. They stocked the condenser and most of the fittings for my update, and have also helped me with other projects, so I wanted to keep my money local with a family run business that supports local car shows...not trying to disrespect the guys that run the forum.

I noticed the dip stick portion in the manual, but thought it was odd in the fact no specific level was stated. The other era Fords such as the Thunderbird used a 6 piston compressor {delco?} and there were specific charts for oil levels.

385 block fords got the A6 compressor, smaller engines got the York. The dipstick is described in the York service manual.

Quote

I called Classic Air on the POA and the gentleman I spoke with was adamant about the charge only being 3 lbs 4 oz; Old Air products {supplier for the POA eliminator} showed 4 lbs 4 oz for some cars, 4 lbs 8 oz for other Ford intermediates.

Once you significantly modify a system, the capacity becomes unique to that vehicle. Some testing will be necessary to find the correct charge.

Quote

I re-verified with the local shop, and they suggested I verify at Idle if in fact I have 30-40 PSI on the low side, and 2.5x temp on the high side, blower set to low, and windows and doors open.

That test is useless, as you have just discovered. You need to test at maximum load. Cabin fan on highest speed, doors open & 1500+ engine rpm. Unless you plan to idle around town with the fan on low.

Quote

Hopefully I was correct on my original charge, and didn't overcharge the system.

You probably are, unless you got a lot of air in the system.

I am assuming you put a fresh receiver / dryer in the system when you rebuilt it. Check to see that the flow direction through it is correct. A backwards R/D can cause a lot of trouble Clean the sight glass while you are there.

Pf condensers can hold less refrigerant. The compressor you have now has less internal volume as well as less displacement per revolution than the OEM unit.

The OEM compressors both had sumps. They did not circulate oil, except for the small quantity that goes past the rings. The SD709 you have now circulates the entire oil quantity in the system,and oil quantities can make a difference in cooling. If you have too much oil the system will not cool well. How much oil do you actually have in the system now?

I don't think the STV eliminator is a good choice, but you are already there. You seem to be in a time crunch, so recover the charge & try again. Use the sight glass and your gauges.

There is a process for determining the correct charge, but it requires a good scale & a recovery machine.

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"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.