Chain of events, (cooling system)
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By Skipped_Link - 7 Years Ago
I think the plans for my cooling system have changed a little bit,

The origonal plan went along these lines,

At 175* the shutter stat would activate & open the shutters,

Next the thermostat would ragulate the water temp around 180-185

If the water temp reached 195* an electric switch would activate an air solenoid, which would apply air to the fan, this would continue until the water temp dropped back down to 185* there the fan would be shut off.

Now I am planning on installing my A/C condenser in front of the radiator & behind the shutters, I do not think it would be a good idea to try & operate the A/C with the shutters closed allowing no air movement over the condenser, So I was thinking about removing the shutter stat & replacing it with another temperature switch & solenoid valve to operate the shutters, By doing this the shutters could be opened anytime the A/C compressor is running, I would have to install a diode to keep from activating the clutch when ever the shutters come open due to water temperature, but that is easy enough to install.

If I do this I was thinking about bumping the "shutter open temp" up to 185*, so now the cooling cycle would look like this,

Water temp rises & engine temp is maintained at 180-185 with the T-stat,

At 185* the shutters would open, (only closing if the temp dips down to 170 for some reason)

If temps continue to rise the fan will come on at 195* & shut off again when cooled down to 185*, as it would in the first plan,

Any reason this should not work?
By wayne graham - 7 Years Ago
Probably a dumb question but why are you using shutters? With AC condenser in front of radiator I think you have found out why they quit using shutters. You can make it work but I have to wonder why. I mean this as a constructive question and not criticism. Wayne
By Skipped_Link - 7 Years Ago
Because they are on there, & I have an issue with things not being functional, or real, (I hate laminate flooring too, functional, but not real)

Probably the biggest reason is they are on there & I would like them to work properly, but also to help build & maintain heat, when I drove the truck home the first time it would not hardly reach operating tempertaure, (this was with the shutters open & a direct drive fan),

Now I have the air actuated fan, but at freeway speeds the only way to slow the air flow is shutters,

(edit) The T-state shoudl be maintining the coolant temperature, I'm just not sure how effective it will be on it's own with no real load on the truck.
By glenn akers - 7 Years Ago
I my self wonder why you want the shutters to work. I my self would keep them but leave them open and use a 190 degree T stat.Then turn on the air fan clutch 10 degress above the T stat.Use the werdstat brand for a T stat. It will hold the temp up better at idle.Leave as much of the heat in the coolant as you can as long as its still in a safe range.If its a older engine it should run some cooler than my specs.Newer engines runn better at 200 or above.
By Skipped_Link - 7 Years Ago
glenn akers (15/01/2013)
I my self wonder why you want the shutters to work. I my self would keep them but leave them open and use a 190 degree T stat.Then turn on the air fan clutch 10 degress above the T stat.Use the werdstat brand for a T stat. It will hold the temp up better at idle.Leave as much of the heat in the coolant as you can as long as its still in a safe range.If its a older engine it should run some cooler than my specs.Newer engines runn better at 200 or above.

This is on an older NTC350,

Good info int the T-stat, thanks I'll look into that brand, & see if the local parts store can get one for this engine.

I had another thought as well, I could leave everything as is, With a 175* shutter stat, once up to operating temp it should never close anyway, just add a solenoid valve to open the shutters if the A/C comes on prior to the shutters being open due to coolant temperature,

You guys are correct, with better thermostats, & clutch fans, shutters are not really needed, but anyone can just leave them open, & the novelty of having them operational is appealing to me.
By wayne graham - 7 Years Ago
I like the idea of just keeping them open. With the AC condenser blocking air flow and the clutch fan I doubt you will have a problem maintaining temp. I do understand about wanting them cause they are there. I too like everything to work. Wayne
By glenn akers - 7 Years Ago
I think that would work.Back when shutter were still here cummins was common to have them blocked open and then the weirdstat was to be installed. I think remenber seeing a upgrade for that from cummins or maybe from the truck side.
By Junkmandan - 7 Years Ago
As Glenn said the Weir brand of thermostat was the salvation in a Detroit engine to maintain heat, and keep it regulated. This brand of stat became standard in the mid '70s. Although you never told us the make of truck, the type of shutter control,[straight mechanical from a lower radiator outlet or air operated with control in thermostat housing], the reason OEMs all went to temperature controlled fans was to simplify the cooling system temperature control and make it more failsafe.
By Skipped_Link - 7 Years Ago
Dan the truck in question is my 61 Peterbilt 281, the build thread is in the "Members trucks" section & can be seen here,

I believe the shutters are made by Cadilac (sp) & are air operated via a shutter stat at the T-stat housing, the truck used to have an air cylinder at the top of the radiator that operated a bell crank & rod down to the shutter slide bar, since the bell crank was missing & the cylinder leaked, I used a cylinder off of a Pack brake (5.9 cummins exhaust brake) & built my own mount to hide everything behind radiator side shroud/cover,

Here is the shutter stat

By deguitars - 7 Years Ago
I had these two diagrams which may or may not be of any use to you. One day I will be trying to make all of this work too!

By Geoff Weeks - 7 Years Ago
the way they were run when shutters we used was:

If the shutterstat was in the top tank or waterrail (like yous is) the shutters opened 10 deg ABOVE the (engine) thermostat, if it was in the bottom tank it opened at the (engine) thermostat setting (return water temp set to engine stat opening temp).

The fan was set (when fan clutch used) for 5-10 deg above shutter opening.

This ment with a 170 deg engine stat, the rad had 180 deg water before the shutters opened and 190 deg before the fan came on. which was about ideal for an older engine.

An electrial bypass was used when the freon compressor is on. With the manual control you have, there is no way to overide the shutter control without useing a double check valve and an air solonoid.

The main reason for shutters was better temp control, but a side benifit was they kept the tubes open in the radiator better by keeping the thermostat (and therfore flow) open.

If it were me, I would replace the mechanical control with a switch and solonoid since you have AC, and wire it so either temp or freon clutch will open the shutter.
By Skipped_Link - 7 Years Ago
Geoff, good info there, I was unaware if what temps certain events take place, that post clears up some questions about that,

As for using the machanical "shutter stat" & solenoid to bypass the system when the A/C is on, that would be easy, the shutters use air to close, with the shutter stat I have now air is supplied to the cylinder, keeping the shutters closed until temps reach 175* at that point air is shut off to the cylinder, (and the air in the cylinder is allowed to exhaust back through the shutter stat) now the cylinder allowes the shutter to open,

I could always just put another solenoid valve between the shutter stat & shutter cylinder, when wired into the A/C it would simply stop air to the cylinder (And exhaust air from the cylinder) alowwing them to open when the A/C is on, When the A/C is off they would work normally, just opening at 175* & not closing again until cooling of below that temp.

Eddy Lucast (16/01/2013)
If you just want the novelty of the shutters working why not have them open when you turn the ignition on and off when you shut down.

That would be very easy, (to easy :cool:) But the novelty of the shutters opening & closing is only part of the equation,

I hope you guys don't take me for being difficult, I'm just weighing my options on what would work best for this truck (which will be seeing pretty light duty in comparison to its former life). This discussion also helps me understand how this system origonally was supposed to operate.

So I have two options I am considering,

Option #1

Leave the shutter stat to open the shutters at 175* & stay open pretty much the entire time the truck is running, then use the newer better T-stat & clutch fan to regulate coolant temperatures, Then simply add a solenoid valve that will open the shutters when the A/C is turned on before 175*,

This will have the novelty of a functioning shutter system, without the cheesyness of just having them work on a switch, this option will also utilize the newer tech with a better T-stat & clutch fan ( newer by comparison of OEM equipment origonally on the truck)

Option #2

Remove the shutter stat all togeather & replace it with a temperature switch & solenoid valve,

This could make the shutters more functional in the system, by using a higher temp switch (say 185*) the shutters would be used more for regulating coolant temps, similar to what Geoff said, more functional & less novelty, However I think the shutters will be opening & closing a lot more often, & then wind up staying open when the A/C is on anyway,

Seems like option #1 would be the easier "makes most sense" way to go. Hmmm, decisions decisions.
By wayne graham - 7 Years Ago
One thing for sure it is your's and whatever you do will be fine with us. We just try to offer a little info and suggestions but no criticism. That is what makes us who we are. Good luck which ever way you decide on. Wayne
By Geoff Weeks - 7 Years Ago
If the condensor is going to be mounted behind the shutter, use a trinery switch on the reciever so it will cut off the compressor if something malfuntions rather then blow a hose off.
By Skipped_Link - 7 Years Ago
Got the switch covered, I started on the plumbing today, I'll update the build thread with the details at the end of my days off.
By Brad K - 5 Years Ago

Glad I found this post.  It's helped me figure out what I need to do with my Autocar.  It has shutters that close when air is applied, but also has a fan clutch that engages when air is applied.  A previous owner had rigged up 2 air solenoids to manually override the shutters and control the fan clutch.  There are 2 switches in the cab that control the solenoids. There are also 2 pressure switches under the hood and 2 indicator lamps on the dash that show when the shutters are closed and fan off. 
My fan has been running constantly, it never shuts off, and I finally tracked it down to the fan solenoid, it's stuck open.  I'm planning to replace that solenoid, and rewire/replumb the whole thing.
My plan is to put in a normally open solenoid for the fan, powered by a normally closed temperature switch.  The switch will keep the valve closed when the engine is cold, and provide air to the clutch when the engine reaches the set temperature, or I can manually turn on the fan by cutting power to the circuit, or if power fails the fan will default to ON.
Shutters will be controlled by the Shutterstat which is normally open, keeping the shutters closed until the engine reaches the shutterstat temperature.  I'll provide the shutterstat with air through a normally closed solenoid that is powered when ignition is on, and can be shut off manually, and will open the shutters if the circuit fails.  (hopefully this is how it is already setup)
I don't know what settings the water thermostat, shutterstat, or current temperature switch have.  I'm planning to ensure it has a 170* thermostat, 180* shutterstat, and 190* fan switch.
Here's a picture of the current setup of solenoids, mounted above the aftercooler.

By Brad K - 5 Years Ago
Thanks for the welcome Tony. 
My Loadking is a hydraulic neck.  The landing gear is on the end of the hydraulic cylinders that fold the neck.  When hooked to the truck, you extend the landing gear, unhook the truck, lower the landing gear, and the neck folds down, reverse the process to fold up.  There's also a proportion control on the cylinders to level the trailer when lifting or lowering.  I'm not sure what weight the neck will lift and still fold up, but I'm planning to carry my Jeep CJ5 on the neck deck.  I tested it with the front end of my 3/4 ton dodge w/ 5.9 cummins on the front deck.  It lifted that just fine.  My wet line on the truck isn't hooked up yet, and I've got the wrong pump anyhow.  It's high volume dump pump, I need a high pressure pump, so I'm using a log splitter to operate the trailer until I mount a proper pony motor.
I'm planning to use the trailer to haul my 1903 9HP Case steam traction engine, 1927 Ford Model T on the rear deck, and Jeep on the front.
I don't want to stray too far from the topic of this thread, but here's a picture of the Loadking patent for the folding neck.  I'm replacing all the wiring and air system on the trailer, so I could start a new thread to detail my progress and show off the trailer.  I'll also be adding the pony motor and a hydraulic 20,000 lb winch.
By Eddy Lucast - 7 Years Ago
If you just want the novelty of the shutters working why not have them open when you turn the ignition on and off when you shut down.
By Tony Bullard - 5 Years Ago
Welcome to JOT, Brad. You understand and have explained your cooling system controls well. I like your strategy of the controls defaulting to a safe state if a component fails. Well thought out.

I love your Acar. How does your folding goose neck operate? My Hyster is cable operated. I've heard some are hydraulic but I can't picture how that would work.
By Tony Bullard - 5 Years Ago
Thanks for the explanation Brad.
It would be great to see a new post in Members Trucks to show your trailer build with the hydraulic power pack and winch mount.