Bus Conversions dot Com Bulletin Board
July 29, 2014, 10:13:07 PM *
Welcome, Guest. Please login or register.

Login with username, password and session length
News: If you had an E-Mag Subscription: The dog will not eat it.
   Home   Help Forum Rules Search Calendar Login Register BCM Home Page Contact BCM  
Pages: 1 2 [3]  All   Go Down
  Print  
Author Topic: rooftop air  (Read 8807 times)
tucsontattoo
Full Member
***
Offline Offline

Posts: 141


1962 4106


WWW

Ignore
« Reply #30 on: May 09, 2006, 01:07:38 PM »

Drivingmisslazy
   Thanks for the input> I have a 4 KW Onan (air cooled) running on propane. All other propane app. in the coach run fine. Gen. will not start  or continue to run while moving. Cannot duplicate the problem under any stationary conditions.Any ideas?Huh?
Logged

we do things three ways,good,fast or cheap. PICK TWO!
JackConrad
Orange Blossom Special II
Global Moderator
Hero Member
*****
Offline Offline

Posts: 4446


73' MC-8 8V71/HT740 Southwest Florida


WWW
« Reply #31 on: May 09, 2006, 02:26:24 PM »

Perhaps bus aerodynamics are causing a reduction in air flow across the generator when running, causing the overtemp switch to shut down the generator?  Cooler day would allow it to run longer before shutting down.  Jack
Logged

Growing Older Is Mandatory, Growing Up Is Optional
Arcadia, Florida, When we are home
http://s682.photobucket.com/albums/vv186/OBS-JC/
tucsontattoo
Full Member
***
Offline Offline

Posts: 141


1962 4106


WWW

Ignore
« Reply #32 on: May 09, 2006, 03:29:20 PM »

Hummmmmm  just might happen, will look into it!

                                       Greg
Logged

we do things three ways,good,fast or cheap. PICK TWO!
tucsontattoo
Full Member
***
Offline Offline

Posts: 141


1962 4106


WWW

Ignore
« Reply #33 on: May 09, 2006, 04:00:15 PM »

Nope not an over heat thing, Won't start while moving with the gen dead cold. Gonna keep lookin.........
Logged

we do things three ways,good,fast or cheap. PICK TWO!
NJT5047
Hero Member
*****
Offline Offline

Posts: 1942





Ignore
« Reply #34 on: May 09, 2006, 07:28:30 PM »

How long after you're driving does it shut down?  When it won't start, is it turning over and not lighting up.....or does the starter not turn the engine?   
Where does your liquid line exit from the LP tank?   Out the top of the tank?  Have you tried topping off the LP tank? 
Is anything electrical running off the genset when it shuts down? 
Jack seems to offer the most plausible idea so far...there have been liquid cooled gensets that wouldn't cool when driving at highway speeds...the airflow thru the radiator was "reversed" or "cavitating" due to aerodynamics of the bus body when underway. 
I assume that there are no valves or solenoids in the generator line between the LP tank and the generator?  The liquid line may have a faulty pickup, yet the "vapor" RV  appliances are  fed with another line and would  continue to work.  If the liquid line surged or slugged vapor, the engine would quit.  If a solenoid cut it off, the engine would still run for a good bit before it ran out of fuel.   This is a liquid LP unit?? As opposed to a vapor gas unit.   I believe we covered this early on.   
Are any removeable bus body covers that are  convering the generator?  The genset box factory covers must remain in place to cool correctly.   If no solenoids and the LP tank is 75% or better, I'd put my money on heating.   
While you may not wish to fool with this idea, but maybe a line could be attached to the overheat switch so that it's function could be monitored from some vantage point inside the bus.   Could be the generator head overheating and shutting the engine down...?   Not sure that Onan has overheat protection on the gen head. 
Be gone for a few days...expect to hear that this problem has been resolved when I return! 
Stumped, JR  Huh
Logged

JR Lynch , Charlotte, NC
87 MC9, 6V92TA DDEC, HT748R ATEC

"Every government interference in the economy consists of giving an unearned benefit, extorted by force, to some men at the expense of others.”

Ayn Rand
NJT5047
Hero Member
*****
Offline Offline

Posts: 1942





Ignore
« Reply #35 on: May 09, 2006, 07:38:03 PM »

Just one more thing...if this is a liquid line genset, do any of the LP components require accurate barometric pressure (converter, regulator?) to function?  Someone familiar with liquid line small engines would know the answer to this.   The airflow thru the generator box may be affecting such sytem components.  My guess would be that the baro pressure would be significantly reduced when underway.  This would be especially true if the unit is behind a large mudflap. 
If the unit won't start, but turns over at highway speeds....try sealing up the generator box completely so that the bus airflow cannot act on the LP components...try starting it.  If it starts...viola...if not, forget this tack.   If it starts, the point is made, turn it immediately off before it heats up.   This seems to have been a problem from the gitgo.  Was this a professsional conversion, and if so, is the converter still around??? Or any of their conversions with similar generator setup.  May be some interesting history.
Best, JR
« Last Edit: May 09, 2006, 07:40:09 PM by NJT5047 » Logged

JR Lynch , Charlotte, NC
87 MC9, 6V92TA DDEC, HT748R ATEC

"Every government interference in the economy consists of giving an unearned benefit, extorted by force, to some men at the expense of others.”

Ayn Rand
tucsontattoo
Full Member
***
Offline Offline

Posts: 141


1962 4106


WWW

Ignore
« Reply #36 on: May 11, 2006, 08:51:14 PM »

OK.... Here is the latest   When I got the bus the fellow I got it from had re skined the doors on the bays doing away with the intake grill for the gen set bay.Figured with the bottom of the gen box open it wouldnt matter. Add to that picture the fellow who built the coach thought it would help his cooling to leave the bottom of the sound box wide open.Then.....somewhere along the way someone added a fome filter cover to the air cleaner element NOW... I start the gen set, turn on the ac's and drive down the 2 lane about 45 or 50 all is well... Hit the interstate and bring her up to about 60  still running fine. Push her over in the fast lane run her up to about 65 and no more gen... I was pulling a vacume on the sound box with a restricted air intake, so the vacume accuated propane regulater feeding gen engine shuts off fule to engine.....That is what it was.Not movtng, just moving fast!!! Fianly figured it all out, Couldn't have done it with all the thoughts and mabie its the kinda input you guys came up with, Thanks so much for all your help. Goterdone

                                           Greg


Logged

we do things three ways,good,fast or cheap. PICK TWO!
FloridaCliff
Hero Member
*****
Offline Offline

Posts: 2458


"The Mighty GMC"




Ignore
« Reply #37 on: May 12, 2006, 05:10:55 AM »

Greg,

Excellent news and good troubleshooting.

Its always an extra challenge when you have to unfix what others have fixed.

Cliff
Logged

1975 GMC  P8M4905A-1160    North Central Florida

"There are basically two types of people. People who accomplish things, and people who claim to have accomplished things. The first group is less crowded."
Mark Twain
tucsontattoo
Full Member
***
Offline Offline

Posts: 141


1962 4106


WWW

Ignore
« Reply #38 on: May 12, 2006, 09:37:50 AM »

  Amen to that Cliff,  Thanks  to Jr's input and your input I was able to move through all the possibilities allot faster. What really got me thinking was an old picture of my bus before the new door skins were installed. I think the final fix will be to have louvers cut for the cooling air intake and I'm going to plumb the engine (gen set) air intake through the sound box wall so I'm drawing intake air from inside the bay and not from inside the sound box.

                                                               Greg
Logged

we do things three ways,good,fast or cheap. PICK TWO!
Pages: 1 2 [3]  All   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.18 | SMF © 2013, Simple Machines Valid XHTML 1.0! Valid CSS!