A/C Installation

With the condenser in front of the radiator, it has to be warmer the way I see it.

I haven’t had my fan kick in while servicing it. But we’re most likely not as warm as your area.

It comes on in traffic at a stop and fades out once I’m going. It sounds all right to me. Id keep an eye on it and see if it stays consistent.

It sounds as if your clutch isn't coming in soon enough.  Can you take a reading with and IR thermometer and find out where it is coming in?

Is there room to get the electric fans and shroud in there?  Bill didn't think so on Darth, but maybe yours would fit?  If it was me I think I'd try that and see if it helps - assuming you have all the bits needed.  That would give you the ability to tune the on/off temps to where you want them.  And you could have a light that tells you when they are on.

As for the idle speed, Big Blue's idle speed didn't use to change enough to even notice with his A/C.  And that was when the engine was dropping at least one cylinder, if not two, at idle.  So I'm surprised that your idle speed is dropping that much.

Oh, and I forgot the coolant temp.  I couldn't see any change in it when the A/C was on either.  And I have an aftermarket gauge.

I know this may be a stupid question but here goes, Are you sure that you have the correct fan clutch? There are two listed for your pickup, one with out A/C, E3TZ 8A616-L and one with A/C, E3TZ 8A616-P. Having the wrong fan clutch could be the difference in the engine temps and the higher pressures you are seeing. Same thing if you have the wrong fan shroud and fan.

I also saw that you said that the idle was down to 500 rpm with the A/C on. Correct me if I am wrong, shouldent there be an idle kicker on the carb that is supposed to kick up the idle when the A/C is on?

Thanks all. I'll do some more testing this afternoon.
I bought the Hayden 2799. I believe it's correct with a/c but was wondering the same yesterday.

A little tidbit I found while researching your fan clutch.https://youtu.be/UHWxqRWt9Kw

Good find Steve. Never knew they could be adjusted.

Just ran out and did some testing after church. Slightly different behavior than I saw yesterday and curious to see what you guys think.

Builder said to use a 195 thermostat but when I sent all the details to Scott for the recurved distributor he said to use a 180 so I've only ever ran the engine with that. 4 row aluminum (Champion style) radiator.

This test was inside my metal, uninsulated shop building with no fans running. Outdoor temp is 88 degrees and 60% humidity so it was pretty warm in there.

Started truck. Let it run for just a couple minutes. RPM at 750-780 idle. Park (auto trans) dropped it to 650.

I was taking measurements at the thermostat housing and on the fan clutch itself once the temp got up to O on the gauge.


Housing/clutch/gauge/fan

A/C off

170/140/O-R/off
177/145/R/off
180/155/M/off
185/159/M-A/off
194/160/A/on (stayed on until I shut the engine off)
171/156/M/on
165/148/R/on
164/149/O-R/on

RPM is now at 850

A/C on max and fan on low

RPM drops to 760
No change in voltmeter

Gauge climbed back to R-M and stayed for a few minutes until I shut the engine off

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Anything look alarming with those temps/numbers?
My 400 in the 80 with the numerical gauges hovers between 190 and 210 (when towing).

There should be a kicker and it should idle the engine up.  Spec on my '82 which doesnt have the kicker as it is dealer A/C, its 550 rpm idle with ac off and with ac on its 675 rpm.

Its a big thing I plan on for my fuel injection conversion to go into the software and change the A/C kicker into an A/C idle stepper so I can have a 550 rpm idle if my cam will allow it and have a 675 rpm idle with the A/C on.

On the fans I believe one of those clutches is a rpm based clutch and the other is a thermal clutch.  I know the thermal clutches you find now at the part stores are HD variants and I hate them cause they lock up way too easy and make your truck/van sound like an airplane taking off.  There is also a listing for a flex fan for A/C equipped vehicles as well, the standard non A/C flex fan is a 5 bladed flex fan while the A/C flex fan is a 7 bladed flex fan that is like 1/2" larger diameter than the 5 bladed.  This is the route I personally have gone to try and correct my A/C setup on my dealer A/C truck.  I get 58* ambient temp out of my dash on a 100* day all day long at idle but I feel I could get better performance with the proper air flow and a proper thermostat switch.

Nope, all of these readings look pretty N O R M A L to me. Still cant wrap my head around why someone would tell you to use a lower temp thermostat in a low compression engine, but I am not going to go there.

lol Im still trying to decide what thermostat to run in my 306.  Should be around 9.5:1 compression maybe as high as 9.75:1 but I initially planned on running a NOS OE 195 thermostat but I have many telling me that even with my fuel injection to stick to the 180 I currently have in my smog engine.

Rusty, as you have no signiture, the only thing I have to go on is that you have an 82?. I also understand that on some of the dealer installed AC systems there was no mixer door or valve to shut off the hot coolant to the heater core. The older 359 and 379 Peterbuilts had the same problem. To solve it, we put manual shutoff valves on the engine to stop the flow of coolant to the heater core.

As for flex fans, I dont trust them much. I will have to see if I can find the picture of what was left of the hood, radiator and shroud from my Super Stock( limited late model ) when the flex fan came apart. So much so that every dirt track I have been on over the past ten years, most of them have out lawed them. Not to mention that with a flex fan, it will always sound like an airplane taking off instead of part of the time. Just a thought.

Rusty, I would suggest the 195 thermostat, it permotes better combustion and a cleaner burn( lower HC and NOX). Depending on what race car I am running, two are 13:1 and the other is 10:1( because of rules on ccompression ), I run 195's in all of them.

I don’t believe the 460 engines have the throttle kicker. Can’t remember where or why I saw that.

grumpin wrote

I don’t believe the 460 engines have the throttle kicker. Can’t remember where or why I saw that.

Maybe in the 1985 EVTM?  

Dane, thats why it was a question, because I dont know. 99% of my time is spent on ten to 15 lieter diesel engines and they dont have a problem idling with the ac compressor running and my 5.0 Bronco uses the IAC solenoid to compensate for the load for the compressor.

Yep, 82 F150 flareside 302 C6.  The AC unit is self contained behind the dash.  When it is overcast or raining I can get the interior cab down into the mid 40`s but the compressor cycles at 45*.  I believe that is a result of a aging thermostat switch to control temperature.  Mine from what I remember has a expansion valve which means I could wire it direct and the evaporator would never freeze.  I do know the AC can blow colder even with a full temp engine, its just not able to reach those lower temps be it solar radiation warming the inside up a bit faster than the AC can cool or it could be a non efficient transfer of heat through the condenser.

As far as flexfans goes, ive never seen one fail personally and Ive never had one fail before.  As far as the plane sound goes, the stock OE flex fan on my 82 is quiet and does not present a airplane sound.  I have heard a flex fan making that noise as well but that van had no fan shroud and from what I understand the fan shroud quiets a flex fan quite a bit.  I also believe it is the spacing of the fan, just like a rigid fan with evenly spaced blades will make more noise than a rigid fan with offset fan blades.  The 7 bladed flex fan I have does have two of the blades offset very similar to the OE 7 blade flex fan that I was able to find one photo of.  This mimics the 5 bladed flex fan I currently have that has two blades offset which is supposedly done to promote lower noise emission.

Appreciate everyone's input.
Once I got the actual temps I realized that while underhood it seemed really hot, the numbers weren't alarming.
May try out the dual electric fans sometime though just to see how they compare.

I have had a flex fan fail on me, it was years ago, one of the Flexalite fiberglass ones on a 1964 Falcon with a 260, I was pulling onto the highway and it shucked a blade (one of six). To get home without it vibrating too badly I broke the opposite one off. I think I ended up with a metal flex blade from a junkyard.

Yeah I wouldnt trust the fiberglass ones, one I got is just like the OE ford one, metal blade with 4 or 5 rivets to a steel core.

old55pete wrote

Dane, thats why it was a question, because I dont know. 99% of my time is spent on ten to 15 lieter diesel engines and they dont have a problem idling with the ac compressor running and my 5.0 Bronco uses the IAC solenoid to compensate for the load for the compressor.

And I wasn’t too sure either!

I think Gary nailed it! Probably saw it in the EVTM. Feeling fortunate, my A/C hasn’t given me any problems since I got it going again 2 or 3 years ago.