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| [GMCnet] Running the onan in hot weather [message #319200] |
Sat, 17 June 2017 22:51  |
ron preston
Messages: 46
Registered: November 2016
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Now that you all have soothed my RPM worries . I've always been reluctant
to run the onan for hours when driving in hot weather 100 ° + to run the
AC (my brother always said I was a worry wart)
I have the 6k power drawer , meter says 79 hrs. Sure it's more like 1079
it's always run well and I just changed the oil/filter. It's probably no
problem but wanted any feedback about what I should/shouldn't do? Watch
for etc.
Thanks
Ron Preston,
San jose ,CA
75 Glenbrook Headers, flowmasters
Soon to get auxiliary AC from Jim K?
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| Re: [GMCnet] Running the onan in hot weather [message #319202 is a reply to message #319200] |
Sat, 17 June 2017 23:32  |
Carl S.
Messages: 4186
Registered: January 2009
Location: Tucson, AZ.
Karma: 13
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ron preston wrote on Sat, 17 June 2017 20:51Now that you all have soothed my RPM worries . I've always been reluctant
to run the onan for hours when driving in hot weather 100 ° + to run the
AC (my brother always said I was a worry wart)
I have the 6k power drawer , meter says 79 hrs. Sure it's more like 1079
it's always run well and I just changed the oil/filter. It's probably no
problem but wanted any feedback about what I should/shouldn't do? Watch
for etc.
Thanks
Ron Preston,
San jose ,CA
75 Glenbrook Headers, flowmasters
Soon to get auxiliary AC from Jim K?
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It's NOT a problem Ron. I have run mine all day on the road with the roof AC running. The only issues you need to worry about are having enough gas in the tank (it will 'run out' if the main tank gets below 1/4) and make sure the crank case is full of oil.
Running mine last Summer for several days worth of travel, I managed to run it low enough on oil that the low oil protection kicked in as I was backing into a space and the generator quit. I checked the oil and it was two quarts low. After refilling it, it ran the whole next day on the last leg of the trip, from Payson to Tucson, AZ without a hitch.
I DO have a Fire Fight Halon extinguisher in the compartment just in case. Always a good idea.
Carl Stouffer
'75 ex Palm Beach
Tucson, AZ.
Chuck Aulgur Reaction Arm Disc Brakes, Quadrabags, 3.70 LSD final drive, Lenzi knuckles/hubs, Dodge Truck 16" X 8" front wheels, Rear American Eagles, Solar battery charging. GMCSJ and GMCMI member
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| Re: [GMCnet] Running the onan in hot weather [message #319203 is a reply to message #319200] |
Sat, 17 June 2017 23:37 |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
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Hope you have the outer rubber air seal around the oil filter, as it aids
in keeping the engine cool.
You should also have the air deflector to keep the unit from pulling in the
heated air.
I seldom carry spare parts, but a new board and a 5 amp fuse is always good.
Oh, keep our phone # should you need help on the phone.
On Sat, Jun 17, 2017 at 8:51 PM, ron preston wrote:
> Now that you all have soothed my RPM worries . I've always been reluctant
> to run the onan for hours when driving in hot weather 100 ° + to run the
> AC (my brother always said I was a worry wart)
> I have the 6k power drawer , meter says 79 hrs. Sure it's more like 1079
> it's always run well and I just changed the oil/filter. It's probably no
> problem but wanted any feedback about what I should/shouldn't do? Watch
> for etc.
> Thanks
> Ron Preston,
> San jose ,CA
> 75 Glenbrook Headers, flowmasters
> Soon to get auxiliary AC from Jim K?
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
--
Jim Kanomata
Applied/GMC, Newark,CA
jimk@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502
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Jim Kanomata
Applied/GMC
jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
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| Re: [GMCnet] Running the onan in hot weather [message #319207 is a reply to message #319203] |
Sun, 18 June 2017 03:48 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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I'm not nuts enough to head south in the summer, but last summer I went to Branson, which I do not consider south, and the temperatures were running 100 to 104 during the heat of the day with 90's at night. My Onan quit due to vapor lock problems several times during that trip. An hour of parking in the shade with it pulled out to cool and it would run OK for the next 1/2 hour or so on the road. My main 455 engine was not experiencing any vapor lock problems at the time. My immediate solution was to hide out in an air conditioned store that allowed me to bring my dog inside with us.
My long term fix was to remove the fuel line from the carb to the base of the generator cabinet and cover it with aviation "fire sleeve" and reflective aluminum tape. I figured that is where the gasoline was picking up the most heat. I also covered the fuel pump with reflective tape. I have since then run into two days on the road at 100 degrees on other trips and have not experienced any vapor lock problems. A second solution might be to install or move the fuel pump back to the fuel tank. That is what I'll do next if this ever happens again.
As far as fire extinguishers go, I use to plan installations and sell Halon systems for large computer rooms. Halon works well in enclosed areas, but in areas of high air flow it is almost useless. It needs to be configured and installed way over capacity to keep the area protected if there is air flow occurring during a fire.
Part of our halon installation was electric an shut down of all forced airflow and automatic door closers in the protected areas when the system went off.
There is a lot of air flow in and around the Onan.
Also I notice people are installing these extinguishes on the front cover of the Onan which is away from the probable fire sources which are on the side where the carb fuel pump and gas lines are located, the top of the cabinet where the heat is radiated from the exhaust, and the generator itself which is located on the rear of the unit. So I have my doubts that the halon systems being sold an installed for our Onans are a good solution. I am waiting for an actual Halon deployment in the Onan cabinet to be reported to prove me wrong.
Halon would be a good solution in the refrigerator or propane cabinets where air flow is minimal.
I do have the deflector on the Onan that blows the hot air away from the coach. It was installed when I had the vapor lock problems.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: [GMCnet] Running the onan in hot weather [message #319222 is a reply to message #319215] |
Sun, 18 June 2017 11:25 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Matt,
Are you saying that the Fire Fight went off three times and there really was no fire?
Also when it went off did it have enough Halon concentration to kill the running engine?
Was it mounted to the outside of the front cover?
What did it cost to recharge the extinguisher?
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: [GMCnet] Running the onan in hot weather [message #319233 is a reply to message #319200] |
Sun, 18 June 2017 13:53 |
Ernest Dankert
Messages: 133
Registered: May 2007
Location: Ogden, New York
Karma: 1
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Two things I do for Onan peace of mind. Amsoil (air cooled engines run hotter).
Fire Fight remote head installed inboard/forward of the generator compartment.
Yeah the Halon solution may be imperfect, but better than nothing.
1977 Eleganza II
Ogden NY
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| Re: [GMCnet] Running the onan in hot weather [message #319237 is a reply to message #319233] |
Sun, 18 June 2017 14:40 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Ernest Dankert wrote on Sun, 18 June 2017 13:53Two things I do for Onan peace of mind. Amsoil (air cooled engines run hotter).
Fire Fight remote head installed inboard/forward of the generator compartment.
Yeah the Halon solution may be imperfect, but better than nothing.
Only if it actually puts the fire out. You only get one shot at it and then you walk away if it does not work.
I like the idea of the remote head.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: [GMCnet] Running the onan in hot weather [message #319247 is a reply to message #319241] |
Sun, 18 June 2017 17:33 |
Jim Miller
Messages: 501
Registered: March 2008
Karma: 10
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On Jun 18, 2017, at 5:04 PM, Richard Denney wrote:
> My own Onan had a crack at the exhaust connection that had charred the compartment above it, so it wouldn't have taken much to fan that into flames. That's one of the reasons I switched to the Generac.
Thanks Rick. I can see where an exhaust jet from a compromised manifold might set off the insulation ala the Challenger’s SRB failure.
My coach had similar crusty insulation above the Onan exhaust manifold; however unlike yours my manifold was intact.
I was curious about what was really going on at that area of the compartment and after re-insulating the area with Reflectix I instrumented the compartment with thermocouples to see what was really happening. To my surprise the area above the manifold stayed barely above ambient *while the Onan was running*. It was only after shutdown that the area peaked to around 200F before cooling down. This is documented at: http://www.jcmco.com/gallery/album29
—Jim
Jim Miller
1977 Eleganza
1977 Royale
Hamilton, OH
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Jim Miller
1977 Eleganza II
1977 Royale
Hamilton, OH
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| Re: [GMCnet] Running the onan in hot weather [message #319259 is a reply to message #319222] |
Sun, 18 June 2017 19:23 |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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Ken Burton wrote on Sun, 18 June 2017 12:25Matt,
Are you saying that the Fire Fight went off three times and there really was no fire?
Also when it went off did it have enough Halon concentration to kill the running engine?
Was it mounted to the outside of the front cover?
What did it cost to recharge the extinguisher?
Ken,
That is exactly what I am saying. (At least three.)
It sure did. Think about it, everything is copacetic and BANG the electric plant stops HARD. (Yes, the A/C was running the first time and it took out the bridge.)
So, you run out there only to find . . . Nothing....
It was initially mounted as directed inside the front cover of the Onan. The second time in was inside horizontal over the battery and the last time it was standing up outboard of the battery. Remember this is a 73 23 so things are different.
Recharge was 25$ all but the last. It is still empty as I have given up.
I may have lost count, the logs are out in the coach and I think Mac gave me a new one for one of the times. I did buy two recharges.
Matt
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
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| Re: [GMCnet] Running the onan in hot weather [message #319276 is a reply to message #319259] |
Mon, 19 June 2017 01:35 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Senior Member |
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What you are telling me is good news in a way. Properly placed, It will dump enough halon to stop the engine and it's associated high volume cooling fan that is moving some of that fresh air into the area.
Since the air intake, carb, and fuel pump are all located together, that tells me that properly placed, halon might be effective in a gasoline fire in that area. I still do not know what would happen in a cabinet fire (overhead) or a fire in the actual generator itself. Every coach I have checked has had some scorching or melting in the overhead portion of the generator cabinet.
Most people never look overhead to see what has happened there, because they have to lay on the ground and look up to see it. This is the reason I installed an aluminum shield up there and down the side to reflect and absorb some of the excess heat from that area.
Matt, they make extinguisher triggers with several different melting temperatures. Have you tried one with a higher temperature?
BTW, For Halon look-a-like enthusiasts, Have you looked at this VW solution for use in the generator compartment:
https://jogrusa.com/products/blazecut-fire-suppression-system?variant=16369324485
They make them in 3', 6', 9', and 12' lengths. They do not take much room and could be run all over the sides and top of the cabinet. It will only trigger where the actual heat is. Then it dumps the entire contents at that trigger point. Each longer size contains a proportional amount of additional extinguishing liquid which turns to gas on deployment.
I have seen one and the only drawback is the pipe is fairly rigid but it will bend. I do not know what the smallest bending radius is. Installing it around tight corners might be a problem. If I ever had the generator removed from the cabinet so I could easily work inside, I think I would install 9 or 12 feet of this stuff around the generator cabinet and inside the battery enclosure that is next to the generator.
In their demo they only used a 6 foot one and the engine was not running moving air.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: [GMCnet] Running the onan in hot weather [message #319277 is a reply to message #319200] |
Mon, 19 June 2017 05:12 |
Chris Tyler
Messages: 458
Registered: September 2013
Location: Odessa FL
Karma: 7
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Senior Member |
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I understand the concern for engine temps, but remember ther are a lot of air cooled engines used in very hot climates without problems
You can run a heavier oil if you dont experiance lower temps- I never really get outside FL
I suppose you could get a cyl head temp and/or oil temp gauges to monitor it if you want to worry about it.
Regarding fire issues: I have become a foam fan for anything involving flamable liquids. Dry chemical is effective but leaves a huge mess and ruins electrical components
real halon seems to be getting hard to find
76 Glenbrook
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| Re: [GMCnet] Running the onan in hot weather [message #319292 is a reply to message #319200] |
Mon, 19 June 2017 11:34 |
rjw
Messages: 697
Registered: September 2005
Karma: 4
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Senior Member |
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ron preston wrote on Sat, 17 June 2017 23:51Now that you all have soothed my RPM worries . I've always been reluctant
to run the onan for hours when driving in hot weather 100 ° + to run the
AC (my brother always said I was a worry wart)
I have the 6k power drawer , meter says 79 hrs. Sure it's more like 1079
it's always run well and I just changed the oil/filter. It's probably no
problem but wanted any feedback about what I should/shouldn't do? Watch
for etc.
Thanks
Ron Preston,
San jose ,CA
75 Glenbrook Headers, flowmasters
Soon to get auxiliary AC from Jim K?
I just returned from a 2 week GMC trip from Michigan to Austin, Texas for my son's wedding. Even though I lived in Dallas for a couple of years back in the 70's, I had forgotten how hot it can get in Texas. Because there was no way the dash air would keep up with the 95-100 degree temps (and this was June) I had to run my Onan to power the house air to keep half way cool while driving. Now I know why people down there have 2 air conditioners because 1 does not cut it. At any rate, we ran the Onan for a total of 27.7 hours. If I started it cold, it would run just fine until time to get gas. But when I shut it down for refueling, it would not start again until it cooled, which took a few hours of driving which was annoying because it got hot in our GMC without house air running. Apparently, vapor lock was the cause.
During the trip, I used my IF thermometer to measure Onan temps. I found that when it is running, everything stays relatively cool, which must be because of all the air being moved by the Onan's cooling fan. Upon shut down, things start to get hot (~200 degrees on the exhaust) which to me explains the vapor lock because of the proximity of the fuel system to the manifold.
As Ken B. has suggested, I might move the fuel pump and wrap the fuel line with some sort of insulation. I am also thinking about installing a 2nd air conditioner and a second evaporator for the dash air.
Richard
76 Palm Beach
SE Michigan
www.PalmBeachGMC.com
Roller Cam 455, TBI+EBL, 3.42 FD, 4 Bag, Macerator, Lenzi (brakes, vacuum system, front end stuff), Manny Tranny, vacuum step, Tankless + OEM water heaters.
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| Re: [GMCnet] Running the onan in hot weather [message #319300 is a reply to message #319292] |
Mon, 19 June 2017 14:48 |
TR 1
Messages: 348
Registered: August 2015
Location: DFW
Karma: -7
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rjw wrote on Mon, 19 June 2017 11:34ron preston wrote on Sat, 17 June 2017 23:51Now that you all have soothed my RPM worries . I've always been reluctant
to run the onan for hours when driving in hot weather 100 ° + to run the
AC (my brother always said I was a worry wart)
I have the 6k power drawer , meter says 79 hrs. Sure it's more like 1079
it's always run well and I just changed the oil/filter. It's probably no
problem but wanted any feedback about what I should/shouldn't do? Watch
for etc.
Thanks
Ron Preston,
San jose ,CA
75 Glenbrook Headers, flowmasters
Soon to get auxiliary AC from Jim K?
I just returned from a 2 week GMC trip from Michigan to Austin, Texas for my son's wedding. Even though I lived in Dallas for a couple of years back in the 70's, I had forgotten how hot it can get in Texas. Because there was no way the dash air would keep up with the 95-100 degree temps (and this was June) I had to run my Onan to power the house air to keep half way cool while driving. Now I know why people down there have 2 air conditioners because 1 does not cut it. At any rate, we ran the Onan for a total of 27.7 hours. If I started it cold, it would run just fine until time to get gas. But when I shut it down for refueling, it would not start again until it cooled, which took a few hours of driving which was annoying because it got hot in our GMC without house air running. Apparently, vapor lock was the cause.
During the trip, I used my IF thermometer to measure Onan temps. I found that when it is running, everything stays relatively cool, which must be because of all the air being moved by the Onan's cooling fan. Upon shut down, things start to get hot (~200 degrees on the exhaust) which to me explains the vapor lock because of the proximity of the fuel system to the manifold.
As Ken B. has suggested, I might move the fuel pump and wrap the fuel line with some sort of insulation. I am also thinking about installing a 2nd air conditioner and a second evaporator for the dash air.
Have you tried sliding the genny out when you shut down to refuel? I am in Texas as well, (and have been fighting some vapor lock on the onan) and have found that can help when only shutting down for a short time...
Mark S. '73 Painted Desert,
Manny 1 Ton Front End,
Howell Injection,
Leigh Harrison 4bag and Rear Brakes,
Fort Worth, TX
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| Re: [GMCnet] Running the onan in hot weather [message #319302 is a reply to message #319292] |
Mon, 19 June 2017 16:04 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Senior Member |
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Richard,
You might consider adding a supplemental fan like Johnny's been promoting
or like this one of mine (since permanently mounted):
http://www.gmcmhphotos.com/photos/troybilt-generator-installation/p31703-140-cdddooling-fan-temporarily-mounted.html
That one works very well supplying air to the ToryBilt I've been running,
with NO problems, since 2009.
With such a fan rigged to run with the Onan shut down (perhaps on a
thermostat or a timer?), you might easily alleviate your vapor lock problem.
Oh yeah, it's installed to blow INTO the compartment.
Ken H.
On Mon, Jun 19, 2017 at 12:34 PM, RJW wrote:
> ...
>
> During the trip, I used my IF thermometer to measure Onan temps. I found
> that when it is running, everything stays relatively cool, which must be
>
> because of all the air being moved by the Onan's cooling fan. Upon shut
> down, things start to get hot (~200 degrees on the exhaust) which to me
>
> explains the vapor lock because of the proximity of the fuel system to the
> manifold.
> ...
>
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Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| Re: [GMCnet] Running the onan in hot weather [message #319304 is a reply to message #319300] |
Mon, 19 June 2017 17:34 |
rjw
Messages: 697
Registered: September 2005
Karma: 4
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[quote title=TR 1 wrote on Mon, 19 June 2017 15:48][quote title=rjw wrote on Mon, 19 June 2017 11:34]ron preston wrote on Sat, 17 June 2017 23:51
Have you tried sliding the genny out when you shut down to refuel? I am in Texas as well, (and have been fighting some vapor lock on the onan) and have found that can help when only shutting down for a short time...
I did not try sliding it out during gas stops. In retrospect, it seems like that would help cool it during a fuel stop. Good tip!
Richard
76 Palm Beach
SE Michigan
www.PalmBeachGMC.com
Roller Cam 455, TBI+EBL, 3.42 FD, 4 Bag, Macerator, Lenzi (brakes, vacuum system, front end stuff), Manny Tranny, vacuum step, Tankless + OEM water heaters.
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