Air Conditioner Questions, Hoses, Manifolds, Valves

[dirtymac]

We've had the truck for over a year now.  Through two summers and a winter, we have not heard the fan load up once.  When we replaced our harmonic balancer we had the fan and fan clutch out and I cleaned it.  It wasn't seized up at that time but it was covered in dirt.  As far as I knew at that time, it was functional.  I know a bit more about the way it works now and I'm pretty confident it needs to be replaced.

I'm not sure where we saw it mentioned but someone said there is an audible click when the clutch engages.  We've never heard that.  As for loading up, we have not heard anything or seen anything to indicate the fan ever changes speed.  We've run it below freezing (barely) and now into the 110's and it never seems to change.

We ordered an aluminum radiator from Champion.  The reviews seemed good and others on here have used them.

As for the high pressure switch, I was actually thinking of an electric switch in place of the pressure relief valve.  Something we could wire into the compressor's power similar to the low pressure switch.  From some other threads I found, it looks like that is what the newer systems have.

[dirtymac]

The click is related to the fan clutch not the A/C :)

[viven44]

Gotcha. I saw clutch and assumed it was the clutch on the AC compressor.

[viven44]

On my 351m (same as 400 for fan, etc) I took out the old heavy duty fan-clutch from the 460 and use it on the 351m, it made a big improvement in cooling while idling in traffic.

I replaced the one I took off the 460 with the one below which has been good on my 460 truck
Hayden Automotive 2799

And about the pressure switch... its a fail safe so if you can charge it to the correct amount based on ambient you shouldn't worry about a high side switch, but I'm interested in your approach. If you find a switch that works, I'm all for it and would be interested.

[dirtymac]

That's the fan clutch I have coming.

I think a high-pressure switch would be nice to have but I'm not sure how easy it would be.  I would need to it connect where the relief valve is and that would require at least one adapter for the switches I have found so far.

[mat in tn]

since you already have the ac system charged and running although weeping at the pressure relief. leave all of that for after the radiator and fan clutch are in place and then test the ac while running to chart any differences. these are two totally different systems even though they are related by sharing the fan.

[dirtymac]

We can definitely do that.

We didn't remove the pressure relief valve at all.  The one part we didn't think to check!  We also know now, thanks to a junkyard manifold, that the valve has an o-ring, which we obviously have not changed either.

[dirtymac]

Part of our A/C upgrade is to install a 2-port heater core shutoff valve.  While we are replacing the radiator, we are going to install that valve as well.  To that end, I have some questions.

First, my plan is to hook the valve up on the inlet side of the heater core.  This seems like the best option but I'd like feedback if anyone disagrees.

Second, does the flow direction matter for the heater core?  The reason I ask is that I read somewhere that Ford recommended, at some point, swapping the flow direction yearly.  I can't find a source for that now.  I do see in other posts where Jim and Gary agree the flow direction doesn't matter.  I just want to verify.

Third, while looking at the service manual, I noticed that on the 8500+GVW trucks (which includes ours), the heater core inlet hose was looped up to a bracket on the carburetor choke.  In Gary's shut-off valve instructions, he mentions this when he's describing the difference between the 2-port and 4-port valves.  When we got our truck, we did not have this loop but we have replaced our carb with one that does have the bracket.  However, we are using an electric choke now, so I don't think this loop is necessary unless it did something other than keep the choke warm.

[85lebaront2]

The heater hose loop did two things, during warmup it slowed down the choke opening by having cold coolant, with the engine still warm it help release the choke faster.

The supply hose is the one that needs to be in that clip.

[dirtymac]

Thank you for the info!  I am curious if that setup would have been used with an electric or hot air choke?  We have an electric choke and we have part of the hot air choke tube but it is not connected to anything.

[85lebaront2]

They were used generally with hot air, but could probably be used with electric ones other than the Ford ones with the stud that would be right into the hose. The Carter and Holley 12V electric choke covers have fairly flush with the bakelite.

[mat in tn]

the 400 uses a stove in the intake manifold which is basically a tubular coil in the intake below the mounting plate with a fresh air intake connected to the horn of the carb and a draw tube going to the back of the choke. many of these have rusted away by this time. I did a repair for just this scenario a few years ago on a 351m/400. if I still have the pictures somewhere I will try to post them. if not i can get at pictures at least of the existing system as I still own that truck.
funny story about heater core flow direction. I had an employee a few years back and he had an econline,93-94 I think, family van but his wife complained about no heat. I said I would look at it after work. I quickly determined it was a clogged heater core. so, I pulled both hoses and reconnected the supply hose to the opposite connection with the other open and said start it up. he started it and came out and unfortunately stood right in range of the open pipe. why not, nothing was coming out. till it did! it actually looked like diarrhea. he screamed. it shit on me! any way. that's what happens when we neglect our cooling systems. good coolant prevents rust. rust creates clogs not just holes in block plugs.

[dirtymac]

Matt, I would actually appreciate any pictures you can get me of that setup.  I haven't had the time yet to investigate this, but I know our carb at this setup from the factory.  There is a hot air tube coming from the plate on the intake but it's just blocked off.

[dirtymac]

We have the Holly style electric choke so the stud shouldn't be an issue.

We were not planning to use the 4-port style valve for the heater shut off but we could always consider that in the future if this proves helpful.  I'm not sure we will be able to determine the usefulness though.  Once the A/C is working, it will be running 75% of the year so there would be no hot water flowing through that hose.

I have plenty of hose that so if we end up not needing it or its in the way, we can always shorten it in the future.