| Author |
Message |
james dean boggs (Jd_boggs)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, August 22, 2005 - 12:59 am: | |
My 1981 Flex/Grumman no longer overheats. Thanks to all who contributed with your sugestions. Bottom line is that the fan clutch was slipping and I didn't know it until some clever guy suggested I test the fan clutch by removing the air supply to the clutch. If you could turn it by hand, then the clutch is slipping. Took me 3 hours to remove it and another 2 to install a rebuild. Took it for a 100 mile test drive in the southern California desert between Palm Springs and Indio. Saturday's temp was about 110F, drove the bus at 65MPH on a flat surface, meter stayed at 195F. At 55-60 MPH the temp was at 185-190F. On the grade up to 29 Palms, the temp gage went up to 197F. With that, Im satisfied. I no longer have to drive at 5:00AM in the cool morning until my next destination. hehe
Again, thank you all very much.
PS
I removed the thermal switch (shutterstat) that engages the clutch at 195F. Clutch is always engaged. I'll sacrifice HP and fuel but knowning that the fan is always turning. |
Richard Bowyer (Drivingmisslazy)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, August 22, 2005 - 9:19 am: | |
Congratulations. I know what a good feeling that is to resolve an overheating problem.
If possible, I would suggest you leave the thermostat switch so that it can be engaged if possible. I found out on my Eagle with the clutch disabled it ran way too cool in cold weather. Although I lived in California and and am well familiar with I-10 and the route you travelled, I sometimes went into cold country and could not keep the engine or the interior of the bus warm with the fan running all the time.
Richard |
Jim Shepherd (Rv_safetyman)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, August 22, 2005 - 2:19 pm: | |
James, it sounds like the air clutch was the problem. However, I wonder if your test was correct. The fan clutch that I have adapted to my Series 60 conversion (from a Cummins N14/NTC) engages WITH air supplied. I just tested it to confirm that that is the air logic.
Perhaps there are fan clutches that activate with air removed, but I am not aware of them.
Jim Shepherd
Evergreen, CO
’85 Eagle 10
Bus Project details: http://www.rvsafetysystems.com/busproject.htm (updated 2/17/05) |
james dean boggs (Jd_boggs)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, August 22, 2005 - 5:27 pm: | |
Jim-
The 6v92 comes in different flavors as far as the clutch is concerned. My manuals show at least 2 types. The one I have uses air from the wet tank to collapse a dozen coiled springs. When you release the air preasure, the coiled springs pushes the plates together to engage. |
Jim Shepherd (Rv_safetyman)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, August 23, 2005 - 10:42 am: | |
Hi James. Thanks for the information on the 6V92 fan clutch. I like the idea of a fail-safe system. My 6V92 did not have a clutch.
I was going with a non-clutch system in the Series 60 conversion for the Eagle, but the engine has a control loop for a clutch and it just seemed like the thing to do. The fan clutch that came with the engine was toast. I changed to a Cummins clutch ($$$$$)since the belt grooves were close to an industrial belt groove and allowed me to use industrial belts and sheaves for the drive. Lots more details, but you get the idea.
One of the reasons I considered not using a fan clutch is that we don't get ram air and I think the fan will be clutched most of the time. I will put a pressure switch in the circuit and an indicator light to see how much it runs once I get it running.
Jim |
Richard Bowyer (Drivingmisslazy)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, August 23, 2005 - 10:48 am: | |
Jim, I think you will find that when driving in cold weather below 40 degrees the fan will be freewheeling most of the time.
I know that when I was driving in that type climate I had to keep a throw rug on the outside of the radiator to try and keep the engine warm. I had removed my clutch entirely and that was a big mistake.
Richard |
Jim Shepherd (Rv_safetyman)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, August 23, 2005 - 10:53 am: | |
Richard, you are probably correct and that was the main reason that I paid the extra money and did all of the work.
I would like to think that I will not spend much time at that temperature, but living in CO will probably dictate that. Heck, last year coming back from Bussin 2005, we even got into an ice storm with the stick and staple.
Jim |
james dean boggs (Jd_boggs)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, August 24, 2005 - 12:57 am: | |
I like the idea of having control of the fan clutch with an electric/pneumatic valve and a light to show OFF/ON. It would be easy to re-install the air hose with an electric air valve. I live in the Southern California desert and my travels take me to northern Nevada (another desert) my next trip will be to Baja California Mexico, yet another desert! Do you see a trend? I like it HOT. But if I see the temp at 175F after a good cruise, I'll just throw the switch and disable the clutch. |
Tom Caffrey (Pvcces)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, September 04, 2005 - 8:11 pm: | |
James, I don't know if you did the math, but there is every reason to believe that running the fan when you don't need it will cost you more than a gallon per hour in fuel.
At today's prices, that could amount to $25 per day of driving without any trouble. And the fan running all the time just makes the belt wear faster, if you have a belt.
There's two more reasons to make sure you have a working fan clutch.
For what it's worth.
Tom Caffrey PD4106-2576
Suncatcher |
james dean boggs (Jd_boggs)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, October 12, 2005 - 1:42 am: | |
Tom-
I'm going to take your advise. I'll save a few bucks and the engine will actually run better during these cooler days. No matter what I do, the engine can only get up to 175F. But mostly 170F. Seems too cold to run properly. I will re-install the fan clutch air supply and shutterstat. |