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Actuator, Air Fan Clutch for M923a1

70deuce

70deuce

Active member
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Franktown, CO
Didn't want to pay for a new shutter stat so I installed my manual fan actuation mod. Spent about $25 on the parts and now have complete control of the engine fan from the cab. Got a dual purpose switch from Erik's Surplus. It is an air switch and an single pole electric switch. The air side bleeds off pressure when turned off so its perfect for the fan clutch. Fan disengages within 5 seconds when switched is placed to the off position. Plugged the shutter stat tap on the crossover pipe. I joined the two lines in the engine bay together and used 1/4 inch push lock connectors and 1/4 inch black air line to run in to the cab and the switch. I used two 90's at one connection because I had those parts. A straight connection will work fine. I wired an aircraft post warning/status light to the electric side and it just happened to be blue. I will try to find some white dry transfer lettering to label it "engine fan". I just monitor the engine temp regularly which I do anyways and as it approaches 200 degrees I turn the fan on. When it drops below 185 I turn it off. You don't need the fan very often when driving. These engines run fairly cool while in motion. Running the PTO driven gear static and in parades you sure do. Another bonus of this set up I can turn the fan on for the 5 minute cool down period before shutdown. That noticeably cools it down before the engine is shutdown. I will put a parts list together shortly. Also I found I nice looking Cummins badge that uses good 3M double sided tape to attach it. Seems to be stuck on there good.
 

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I

idbankrman

Member
55
0
6
Location
Castle Rock CO USA
I have an A2 truck but the pictures you posted look the same. You can buy the actuator directly from the manufacturer. I think they are used on a lot of stuff. However I rebuilt mine with new O rings from a harbor freight O ring kit and it works fine. Just unscrew the back of it and gently withdraw the piston. You have nothing to lose if it doesn't work anyway.
 
DJones

DJones

Well-known member
Steel Soldiers Supporter
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Location
New Palestine Indiana
idbankrman said:
I have an A2 truck but the pictures you posted look the same. You can buy the actuator directly from the manufacturer. I think they are used on a lot of stuff. However I rebuilt mine with new O rings from a harbor freight O ring kit and it works fine. Just unscrew the back of it and gently withdraw the piston. You have nothing to lose if it doesn't work anyway.
Click to expand...
Who is manufacturer can you post the link? I constantly run into dead ends or they say its sold. I have rebuilt one but the other truck is missing half of the parts.
 
JJP

JJP

New member
23
0
1
Location
Erie, PA
I found a supplier from another thread. They do not have the originals which were manufactured by Evans but have a different manufacturer they said will work with no mods for between $40 and $65 depending on the probe length. Does anyone know the probe length? I have not had time to check it yet. I talked with Larry at Superior Turbo & Injection Detroit MI 313 842 4616.
 
J

jwesley74

Member
123
8
18
Location
Englewood, FL
70deuce said:
Didn't want to pay for a new shutter stat so I installed my manual fan actuation mod. Spent about $25 on the parts and now have complete control of the engine fan from the cab. Got a dual purpose switch from Erik's Surplus. It is an air switch and an single pole electric switch. The air side bleeds off pressure when turned off so its perfect for the fan clutch. Fan disengages within 5 seconds when switched is placed to the off position. Plugged the shutter stat tap on the crossover pipe. I joined the two lines in the engine bay together and used 1/4 inch push lock connectors and 1/4 inch black air line to run in to the cab and the switch. I used two 90's at one connection because I had those parts. A straight connection will work fine. I wired an aircraft post warning/status light to the electric side and it just happened to be blue. I will try to find some white dry transfer lettering to label it "engine fan". I just monitor the engine temp regularly which I do anyways and as it approaches 200 degrees I turn the fan on. When it drops below 185 I turn it off. You don't need the fan very often when driving. These engines run fairly cool while in motion. Running the PTO driven gear static and in parades you sure do. Another bonus of this set up I can turn the fan on for the 5 minute cool down period before shutdown. That noticeably cools it down before the engine is shutdown. I will put a parts list together shortly. Also I found I nice looking Cummins badge that uses good 3M double sided tape to attach it. Seems to be stuck on there good.
Click to expand...
VERY IMPRESSED! We were wanting to do this to our last truck but sold it before we could. We just locked fan in all the time. Our 925A2 actuator works fine on our current truck but our 923A2 the actuator is locked "engaged" now. All the other trucks when the actuator failed it wouldn't engage the fan. This one is the opposite. It's locked with fan engaged. Weird. I already have an air toggle switch but doesn't have the attached electric side to it. I think we'll do this with our 923A2.

Thanks for the info and pix!
 
MO MV man

MO MV man

New member
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Location
Imperial, MO
I was driving my M931A2 day before yesterday, it was warm outside and the engine never got hot by any stretch (maybe 190?).
But my fan never came on.
I let it idle, it might have hit 195 but no further.
After shutting the engine down, I took a close look at my fan switch and it had a 05/10 date code and Evans part number.
Went online and found it to be 200 degrees to open and 189 to close. Interesting!
I was under the assumption it'd come on sooner.
That answered my curiousity right there-it hadn't gotten warm enough for the fan TO come on.
Learn something new everyday.
 
max1008

max1008

New member
337
3
0
Location
Blue Bell, PA
mo mv man said:
i was driving my m931a2 day before yesterday, it was warm outside and the engine never got hot by any stretch (maybe 190?).
But my fan never came on.
I let it idle, it might have hit 195 but no further.
After shutting the engine down, i took a close look at my fan switch and it had a 05/10 date code and evans part number.
Went online and found it to be 200 degrees to open and 189 to close. Interesting!
I was under the assumption it'd come on sooner.
That answered my curiousity right there-it hadn't gotten warm enough for the fan to come on.
Learn something new everyday.
Click to expand...
load it up and hit a nice long hill, it will sound like a jet engine.
 
I

idbankrman

Member
55
0
6
Location
Castle Rock CO USA
No secret. I just put it in a vise and used a small pipe wrench to unscrew the cap. You will then see a small tube that you grab onto and withdraw. This is the plunger or moving part of the valve. Be careful removing it. I put new O rings on mine and it works fine. However if the temperature sensitive part of the actuator is not working then it is not repairable.
 
Scott88M

Scott88M

New member
152
0
0
Location
East Greenwich, RI
Thanks got it apart needed a better set of pliers and some more elbow grease. One of the o rings was half gone so I think that will hopefully fix my problem. Truck ran great today but never actually hit 200 so not sure if the fan is working or not but I did notice I wasn't losing my air pressure as much as I was.
 
H

Hawssie

New member
157
0
0
Location
Clayton, California
A lot of trucks, (maybe not military though) have an over ride like that so you can turn the fan on manually if you need to or are starting to go up a big hill etc. Another way to get around not using the shutter stat or whatever its called is to just install a typical automotive electric fan relay kit which would come with the thermostat of your choice and relay, then have the relay actuate a typical 2 way solenoid air valve. Then of course you could install a switch of your choice for an over ride for manual use. I did this on my M1070 just because I have nice Condura switches that go with my dash,
 

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M35A2-AZ

M35A2-AZ

Well-known member
Steel Soldiers Supporter
3,222
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83
Location
Tonopah, AZ
I am interested in having a manual fan switch (air or Elec.) but keep the automatic fan switch also.
The problem I am having is venting the air when you turn the manual switch off . I saw the switch from Eric's and that looks great but when the auto switch turns on it will vent out that switch and not turn on the fan.
Do I just need to put in some type of check valves? Do you have a example of one?
 
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