Overheating Genset

AndyG · September 19, 2011, 05:26:59 AM

I'm pretty sure that it is a T connection. I'll have to crawl under to check. About a 1" line feeding into a 5". Maybe I can take a picture under the coach. For reference, the generator is located in the center bay on the driver's side.

robertglines1 · September 19, 2011, 05:35:49 AM

Since we are discussing this on the forum. I was behind you once when it quit. Were you shifting? At St. Joe& Diamond) If so could it be a exhaust pressure surge? Also it happened once on county road at lower speed 40mph , were you taking off?. Outside the box I know. Dad/Bob

AndyG · September 19, 2011, 11:25:46 AM

Quote from: robertglines1 on September 19, 2011, 05:35:49 AM
Since we are discussing this on the forum. I was behind you once when it quit. Were you shifting? At St. Joe& Diamond) If so could it be a exhaust pressure surge? Also it happened once on county road at lower speed 40mph , were you taking off?. Outside the box I know. Dad/Bob

I was to busy hold my toungue just right to make the next gear change. I did not notice if the generator dieing was related to gear shifts or acceleration.

gus · September 19, 2011, 01:08:53 PM

Oh!!

I knew that, being on a bus board threw me off!!

luvrbus · September 19, 2011, 01:25:13 PM

Andy, the generator tied to the truck exhaust is a common installation on toter's and truck type RV's I don't think that would be your problem as there is no back pressure on those exhaust systems

good luck

AndyG · September 19, 2011, 01:31:19 PM

Thanks luvrbus. This is a store-bought conversion (NRC) but that does not mean that they got everything right.

luvrbus · September 19, 2011, 01:41:05 PM

What chassis do you have a friend has a NRC on a Mack and his generator is tied to the truck exhaust we installed a air dam on his and solved his shutdown problem,have old dad build you one 1 ft x 4 inches install in front of the generator fresh air intake installed on a angle

good luck

demodriver · September 19, 2011, 02:51:42 PM

Clifford are you basically suggesting a air scoop? Any problems with water issues while driving if so?

robertglines1 · September 19, 2011, 03:10:56 PM

I this case we are redirecting air currents and creating a minor vacuum

AndyG · September 20, 2011, 05:16:28 AM

Quote from: luvrbus on September 19, 2011, 01:41:05 PM
What chassis do you have a friend has a NRC on a Mack and his generator is tied to the truck exhaust we installed a air dam on his and solved his shutdown problem,have old dad build you one 1 ft x 4 inches install in front of the generator fresh air intake installed on a angle
good luck

Thanks luvr.. The air dam is certainly easiest idea and worth a try. The hot weather is just about gone hear so will have to find out if it works next summer. My toter is on a 1989 FLD120 with a 350 BCIV (Cummins) and eaton 9sp. I forget the rear ratio but geared to run 70MPH @1700 RPM. The truck was a twin screw with 208" WB & 80,000GVW. The previous owner (PO) took out the front driver and stretched the frame before taking the truck to NRC. I can't complain about the conversion. Pretty soild work. There are a couple of things I would have done differently but nothing was done "wrong". This thing with the generator is minor and the days I had trouble were really hot and humid.

TomC · September 20, 2011, 07:45:23 AM

In trucks it has been determined long ago that tying the generator exhaust into the large main engine exhaust creates problems for the smaller engine. If the generator engine stops with one of its exhaust valves open, it lets exhaust and contamination into the engine. At one time Cummins OK'd tying an APU (auxiliary power unit) to their exhaust through the particulate trap. That is no longer accepted. I would always keep both the large engine and the generator engine separate on all accounts. Some have even tied the cooling system together to eliminate the generator radiator-fine if the big engine radiator is large enough-but usually is not the case since most cooling systems on buses are marginal at best. Besides-if one engine goes and it's tied to the other-it would most likely take the other out too (like coolant loss or oily exhaust caused by say a turbo failure. etc.). Good Luck, TomC

gus · September 20, 2011, 12:18:43 PM

For the cooling air intake you want high pressure, not a vacumn!! An air dam in front of an opening does, indeed, cause low pressure (not sure it causes a vacumn though). A lowering of pressure decreases the flow of cooling air.

An air scoop behind a cooling inlet (to the rear of the direction of travel) should create higher pressure at the intake. However, on the bottom side of moving vehicles this is not guaranteed because of so many other things causing air currents to do weird things.

The only real way to find out is to experiment.