Cooling for Angry Bird - compressor spec sought

jclars

Registered User
Since my last posts, there has been a lot of happy driving time with my 1956 F100 powered with the 1989 SC power train. In fact I am feeling so comfortable with it's performance that a buddy and I are planning to do Rte. 66 in it next year. That is if I can get a functional AC unit. The friend thinks it might be nice heading across the southwest portion of the road!

I am working with Vintage Air to come up with components that will work, but have not been able to confirm size of compressor which is stock to this year. I want to use the compressor, as it can utilize the factory mounts. In fact the old compressor is still in the vehicle, but freewheeling for the last 8 years pulling in who-knows-what?

The other question is whether the stock compressor, if replaced with a new unit will accept R134 refrigerant? I have reviewed a few AC repairs on the forum and it appears that it is changed out frequently as an upgrade.
 

35th

Registered User
Yes mine was r12 and it was concerted to 134a before I bought the car 3 years ago and still works
 

KMT

Registered User
Nice to hear you're enjoying the build.

My '90 SC had also been converted in the past. I've since replaced the compressor, w/new clutch, sticking w/134, works fine.

From my notes: "9.03.12, new A/C compressor Autozone online - New w/clutch $115 after core turned in @ store. ‘Compressor Works’ P/N 618121"
 

jclars

Registered User
Thank you gentlemen! As usual, this forum is welcoming and a deep knowledge base.

I have in the meantime had another discussion with a Vintage Air tech who noted that if my compressor was a Ford SF-10, it would adapt to one of their packaged kits.

It appears that this is the correct designation for the T-bird, Is that correct? I would still be curious what the capacity/spec is for the OE unit

John
 

KMT

Registered User
1618418638468.png
FX-15 then....FS-10 now (not SF)

Formula to convert R12~134a: (R12 Charge Specification x 0.9) – 0.25 lbs. = R134a Charge Level
(7.0 x 0.9) - 0.25 = 6.05 oz - please have your vendor confirm.

Also be sure clutch is OE spec. dia., I believe it to be: Maximum Diameter: 5.125 in. ~ Example: Four Seasons 47868
 

jclars

Registered User
Thank Ken -

I will save that sheet. It appears that the cu in displacement at 10.4 is quite a bit higher than the Vintage Air provision (Sanden) which I believe is around 8.5 cid. Perhaps Vintage Air assumes I am using the OEM condenser, but it will be a tight fit inside the F-100 grille. Is this the critical element on the higher compressor rating?
 

KMT

Registered User
My opinion....you may risk giving up a bit of performance moving to R134a ( a very subjective statement, so...) - that, coupled with an 18% reduction in CID, might result in an underperforming system. Of course, the cabin of the truck is smaller than that of the SC...wild est. 120 cu.ft vs. 200 cu.ft., meaning the truck has 40% less interior to cool, which gives you a statistical 22% less space required to cool.

...is this the critical element on the higher compressor rating?

Perhaps. My suggestion is to toss the OE condenser, and opt. for a more modern unit, that is narrower, but more efficient (parallel flow). Benefit is less radiator coverage and need for slightly less R134a. There are several threads here on the condensor swap, goal being to unblock the stock IC intake area.
 

jclars

Registered User
Is there some sort of inverse relationship on cubic inch displacement, as I was thinking it would be an increase of CID?

I will check out those change-outs, but my prime objective was to leave the engine as stock as possible. Plus I don't have those nasty SC shock towers to contend with!!
 

KMT

Registered User
A direct (CID) comparison may be moot, as a Sanden uses different technology - I'm led to believe that makes it's lower CID more efficient. I would give OE specs to VA and trust their advice ;)
 

jclars

Registered User
Thanks Ken - they approved the FS-10 to work with their Sure Fit line of evaporators, so now I have to figure that puzzle out, as the underside of my dash is filled with SC electronics and wires! Maybe even some left over AC components!
 

jclars

Registered User
I found that the Vintage Air unit I was considering was not going to fit with the SC mods that are in place. Mainly the center console placement and the computer on the inside firewall. Just by chance I came upon a company called Old Air Products, who have a kit specific to the 56 F100. After getting dimensions from them, I will be able to move the CPU to the side and fit their smaller unit in beside it.

They also confirmed I would be able to use a stock SC compressor. However, I am thinking I want to bypass the SC electronics and let their controls take over. Am I correct in my assumptions that the only electronic connection to the compressor is for the clutch activation? (a 2 conductor terminal is visible on top). Are there any other electrical signals that I need to isolate?

Thanks,
John
 

KMT

Registered User
Power to the A/C clutch control is via the IRCM, or WOT cutout relay (not all years?). Both are overseen via the EEC.

Not involving the compressor: vehicle speed based radiator fan control (off over 40 mph?)?
 

jclars

Registered User
Thanks Ken. Is power to the A/C clutch full 12V? Also, the Old Air system is provided with a binary safety switch, but they have an option for a trinary to operate the fan. I am thinking this is the cleanest install since the SC controls were abandoned/terminated when I moved the engine from car to truck.

I am now wondering if my fan is even operable. It rarely comes on, even at idle. Is this common? My temp gauge is always well below the midpoint. What is a good way to test fan operation?

If I bypass the IRCM for the third party AC system,, would it be best to use the high speed side of the fan?

Thanks again!
John
 

KMT

Registered User
What is a good way to test fan operation?

See comment #7 in the linked thread.

...and...

- be sure audio is on

would it be best to use the high speed side of the fan?

Ford doesn't engage hi unless the fan is already spun up on lo - torque for hi alone pulls excess amps and a danger to the wiring and supply systems.

is power to the A/C clutch full 12V?
See the spec chart above
 

jclars

Registered User
What a fantastic memory you have Ken! I will digest this to see how to incorporate it into the Old Air system.

You don't have the cfm ratings for each speed in your memory bank do you?

Thanks!
 

KMT

Registered User
No specs I can find, sorry - Anecdotally, we're told thunderbird e-fans are in the 2400~2800 CFM range.

You're going to let me know the next time you come thru Salem w/that truck right? ;)

Ken
 

jclars

Registered User
Good chance this summer. My buddy wants me to do some mini road trips with it before we hit Rte 66 next year.

My family have rented a house on the coast by Yachats at the end of June, but not likely the wife would drive the truck. Fun roads down there though!

Where is the SC rendezvous this year? And in 2022?

Back to topic - Is there a way to step that fan low to high separate from the ECU? Some sort of electronic auto timed switch if there is such a thing?
 

KMT

Registered User
I think you'd need to add an aftermarket fan controller that conditionally triggered the hi side based on (a) lo already being energized and (b) the target higher temp* being reached.

My opinion is that if conditions are such that hi is lit up, it's time to reconsider what it is that's making that happen. I don't think hi is a routine cooling strategy...just for emergency.

Errata:

The low speed fan comes on at 0.37v coming out of the ECT, at it's connector. Must be above 50° ambient.

Strategy/sequence:
• 0.60v = 194°, below N on the gauge, stock thermostat is full open @ 192° ~ 195° depending which is installed. My SC has a 192° stat as of 2.15.19 that went in back in 2017.
• 0.53v = 200°~ 205° and N on the gauge
• 0.46 left side of O, 212~215°
• 0.42 almost straight up O ~ R, 218°?
• 0.37/.39 220°~222° low speed fan turn on, left side of R on gauge
• Fan comes on and drives it back to N +/- depending on load and ambient air temp, etc.

Notes:

  • lo speed on at 222° and above / off at 214°
  • *hi speed on at 228° and above / off at 220° …if hi is on, it will drive temp down and shut off at 220°... lo will also still be on, pushing temp down to 214, then fan is all off.
  • A/C on runs lo speed fan, not hi.

No meets on the left coast I'm aware of...something planned east, I think.

2021 Saturday lunch shopping list
 

jclars

Registered User
that simplifies it. I will simply have low switch on with the aftermarket AC switch and let the computer do it's thing for the engine temp.
 
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