Great Plains Crossing Calamity

[Scott & Heather]

Doesn't it have to do with oil pressure being super low during normal idle? In any case, I often see coaches in the winter idled for hours. I've done it too. Just have a good CO sensor in the bedroom...make that two of them. We don't want to sleep forever...going to sleep with the coach idling away is very peaceful actually. Oh, and for the record, we have two sheets of 90 minute FIREROCK fire resistant sheetrock under the bed and behind it. Gives us some time to get out if there's an engine fire.

[artvonne]

  An engine is an engine, basically. Certain engines have peculiar idiosyncrasies that often need work arounds, but most are manageable. In boats they dont want anything to reach tempertures above the flash point of gasoline, so they would run 140° T stats. Not sure about diesels in boats, but I believe they run the same temps. Not because of the flash point of diesel, but the various oils and fumes that may exist in proximity to the engine which could have flash points above 140°. In any case 140° is about the minimum temperature you want to run any engine at.

   Another issue is piston to bore clearance. Pistons are made to work at full operating temperature. Because the Crown of the piston operates much hotter than the skirt, the piston is made much smaller at the top, to account for expansion at operating temperature. Running an engine cold for long periods can lead to greatly accelerated piston/cylinder wear because the top of the piston is contracted and it wobbles and flops around going up and down, called piston slap. All you need to do to correct it is get the temps up to 140°. You see big rigs closing off the radiators in cold weather, you need to do the same for the bus, but you also need to monitor engine temps in case outside temps rise or you could overheat.

  Idle oil pressure could be too low, or not, all you need do is check it against specs. Most give full oil pressure at peak RPM not at idle. Likely anything over 5 psi at idle is sort of okay, but I would like to see at least 10 psi, and more wont hurt. Heavier oil, fresh oil, a good oil pump, pressure relief valve adjustment, tighter engine bearings, or speeding up the engine a bit can, or could solve that issue.

  Another issue we've read about is 2 stroke Detroits wetting the exhaust with unburned fuel. Again, some of that is due to cold running engines, engines out of tune, and engines running to slow. And some of it may just be the beasts nature and we may have to live with killing some skeeters and driving Prius drivers insane for a few miles down the road next morning after a nights idling run.

  I also think we should resist pointing fingers. Everyone makes errors in judgment, and only through looking back can we often see them. I've been reading Flying magazines all my life, and for various reasons have always been drawn to aviation accidents and the scarey stories with better outcomes, the "I learned about Flying from that" sort of stuff. They don't post them to point fingers, but to teach us. You can only learn so much reading books and listening to others, you have to go out and live it to really learn and make mistakes. And yes, once in a while some of us make very grave mistakes.

  Its so easy to say you would have done this different, or that different, but maybe you have more experience, or your thought processes work differently than mine, on that day at that time. Maybe a while from now down the road you'll screw up and someone else can say well, I would have done that different. The old 20/20 hindsight thing is really a bugger. I bet if the Donners had known they were only a short way from the summit they would have pushed on and we would never have known of them.

  And then there is truly knowing how dangerous cold can really be. Not only do many people who didnt grow up in cold climates underestimate the dangers, people who have lived in that climate all their life often do as well, or are often even more complacent to it than noobs. Having lived in Minnesota most of my life, 51 years to be exact, 10 years of it in Duluth and never missing a winter, I learned a lot, and saw a lot. Ive seen the thermometer down near -50° once or twice, colder than -40° more than I can count, and probably a combined total of nights below -30° that would reach several months. Ive frost bit my hands and feet, once so bad it hurt for years. I knew a guy who froze to death when his car quit a mile from a Bar he'd left, found less than 100 feet from his car. My dad worked with a guy at Duluth AFB who froze to death less than 2 miles from work after his car quit, also found close to his car. An elederly couple were found frozen embracing each other in a huddle behind a wind break, less than 100 yards from the front door of their house, less than 100 feet from their car, when their car got stuck in the driveway and they set out on foot in a white out snowstorm. We knew a young girl who had both her feet amputated after missing the school Bus and walking home in her tennis shoes. In every case, those people simply werent dressed to be out in that kind of weather, and/or made a bad decision. My flight instructor told me always to dress like I might have to walk 10 miles through the woods. At night. Probably the best advice anyone could ever use.

  But like I said, we often have to put ourselves in a scary position before we see the real danger, and thankfully I learned that quite young. When I was 17 I got my car stuck on a back country rural road, with the nearest house over a mile away. Had I not known better I might have tried walking, but it was more than -10 and breezy and I did know better. I huddled up in blankets and clothes in the backseat, and ran the engine just enough to stay warm. I was awakened at the crack of dawn by an old Farmer tapping on my window. Ya want to get out? He yanked me out with his tractor and I was on my way. Warm. Fully rested from a full nights sleep, and more importantly, alive. Alive means were able to relate our stupid mistakes and goofs to someone wise enough to listen and learn. Dead is just dead and no one ever learns much from it.

 

 

[buswarrior]

On engine idling:

If the engine will be able to maintain something close to operating temp, low idle is fine.

Running any heating, either the coach or the defroster, will pull the engine temp well below operating temps, so run high idle.

Shutters and fan dampers inoperative?  Not good, consider covering the rads or slipping the fan belt off while parked. Slipping the belt off, in conjunction with arctic temps and the heaters working will take care of cooling the engine. This requires some knowledge and some monitoring or what you are doing.

If there will be any appreciable electrical loads on the charging system, run high idle.

MCI owners beware: How is your air drier heating element powered? Many models, the stock wiring was to the coach HVAC switch, so leaving the coach heat turned off will freeze the purge valve. Also, this circuit is often overlooked when the HVAC system is torn out during the conversion process.

For the busnut, a good strategy might be to find the wire in the driver's outside electric compartment and choose a different method of powering the circuit. Often a small 3 amp inline fuse holder in the wire will let you find it, instead of tracing it up from underneath.

happy coaching!
buswarrior