Lister Engine Forum

Slow Speed Diesel Engines => Other Slow Speed Diesels => Topic started by: mauicole on July 03, 2012, 08:04:38 AM

Title: ONAN 11.5 DNAD
Post by: mauicole on July 03, 2012, 08:04:38 AM
Hi all, I just got this Onan/Cummings genset. It has not been run for at least a year.The previous owner was not mechanically inclined and I suspect never had a proper load on her. I haven't found much useful info on the internet yet. Does anyone know about these? I paid $150 for the whole shebang. 

(http://listerenginegallery.com/main.php?g2_view=core.DownloadItem&g2_itemId=7091&g2_serialNumber=1)
(http://listerenginegallery.com/main.php?g2_view=core.DownloadItem&g2_itemId=7093&g2_serialNumber=1)
(http://listerenginegallery.com/main.php?g2_view=core.DownloadItem&g2_itemId=7095&g2_serialNumber=1)
(http://listerenginegallery.com/main.php?g2_view=core.DownloadItem&g2_itemId=7097&g2_serialNumber=1)
(http://listerenginegallery.com/main.php?g2_view=core.DownloadItem&g2_itemId=7099&g2_serialNumber=1)
(http://listerenginegallery.com/main.php?g2_view=core.DownloadItem&g2_itemId=7101&g2_serialNumber=1)
(http://listerenginegallery.com/main.php?g2_view=core.DownloadItem&g2_itemId=7103&g2_serialNumber=1)
(http://listerenginegallery.com/main.php?g2_view=core.DownloadItem&g2_itemId=7105&g2_serialNumber=1)
(http://listerenginegallery.com/main.php?g2_view=core.DownloadItem&g2_itemId=7107&g2_serialNumber=1)



Title: Re: ONAN 11.5 DNAD
Post by: dieselgman on July 03, 2012, 01:12:36 PM
Lister LPW3, and what a steal!!! We have full parts and information for that machine. Notorious for valve-train issues, hydraulic tappets. Carbon build-up can cause catastrophic damage in these so be careful with it!

Always replace water-pump and thermostat around 6,000 hours. Re-torque cylinder head and make sure your ports are clear and clean.

dieselgman
Title: Re: ONAN 11.5 DNAD
Post by: mauicole on July 03, 2012, 07:15:34 PM
That's great Gary. It turns over and belches grey smoke but does not start. (That's why it was cheap) Could that be tappet related? I removed an injector and the tip looked pretty good (the tip is pretty small and there was some carbon, but it didn't look excessive) I guess I would have to remove the head to see if there is excessive carbon build-up.  I hope the catastrophic damage hasn't already happened.  :embarassed: What is the life expectancy of these engines?
Title: Re: ONAN 11.5 DNAD
Post by: mauicole on July 04, 2012, 12:34:57 AM
I re-torqued the head - all bolts were less than a half turn loose. :o Intake ports were clean and the exhaust ports looked good too. Still didn't start. There is a intake air heater that has no wire going to it - I don't see why that would make a difference since it's 70F outside today. Is there a simple way to test the compression on an LPW3?
Title: Re: ONAN 11.5 DNAD
Post by: carlb23 on July 04, 2012, 12:52:45 AM
are you sure there isn't air in the fuel line.  Sounds like you may need to bleed the high pressure injector lines.
Title: Re: ONAN 11.5 DNAD
Post by: mauicole on July 04, 2012, 02:04:05 AM
I bled the bleed screw on the fuel filter and cracked all the high pressure lines at each injector. Fuel is flowing and burning(lots of grey smoke puffing out the exhaust) It fires on it's own several times once I stop the starter while holding the rack open (it has a fuel shut off solenoid). I want it to be something simple but I'm running out of ideas. :-\
Title: Re: ONAN 11.5 DNAD
Post by: dieselgman on July 04, 2012, 02:43:24 AM
Turn over with valve covers off and observe proper valve lift on each and every valve... pay close attention to pushrods, they often are bent on a unit that will not start and run.

dieselgman
Title: Re: ONAN 11.5 DNAD
Post by: dieselgman on July 04, 2012, 02:46:08 AM
This is not one of the longer-lived Listers... some may disagree, but our estimate is about 10,000 hours engine life on the average for this one.

dieselgman
Title: Re: ONAN 11.5 DNAD
Post by: mauicole on July 04, 2012, 03:58:03 AM
Thanks for the help guys. I had this crazy idea that if I took my wife's hair dryer and blew hot air into the intake it might do something. It started up and billowed huge plumes of white/grey smoke out the exhaust. I let it run until my neighbor scowled at me. ;D (about 5 minutes) It's a good thing my wife wasn't around!
Title: Re: ONAN 11.5 DNAD
Post by: Tom on July 05, 2012, 05:13:14 PM
Sounds like you may need a set of injectors. That is usually what white/grey smoke means.
Title: Re: ONAN 11.5 DNAD (LPW3)
Post by: mauicole on July 05, 2012, 10:19:02 PM
Thanks for that Tom. I really hope it's not the injectors :-[

I started it with no load. The grey/white smoke was extreme for the first minute and then decreased a bit but did not go away. I found a PDF manual online:
http://www.set-zeise.de/UserFiles/File/LP%20Workshop%20Manual%20part%20I.pdf
The trouble shooting section says:

Light Blue Exhaust Smoke
Generally as a result of light load. Investigate the load management programme. (pretty sure the previous owner had no such programme)
Heavy Blue Exhaust Smoke
Lubricating oil passing the piston rings. Check the crankcase vacuum. Check for wear.
Stuck, worn or broken piston rings. Check for damage, decarbonise, replace the rings.
Worn cylinder bore. Replace the piston and piston rings.
Overfull oil sump. Correct the level.

For some reason the dipstick is really loose and seems to show too much oil. I had to borrow the battery from my truck to start the beast the other day, but my wife has the truck today. I'll give it another go tomorrow after I get the oil level right. I was also thinking of feeding it some propane for 5 minutes after starting to clear out some carbon.

I don't understand why the hairdryer helped it start. It's not cold here.

-Cole
Title: Re: ONAN 11.5 DNAD
Post by: dieselgman on July 05, 2012, 11:13:49 PM
Probably light on compression (or improper fuel atomization), this is why a preheat will help start. Remember, the air must compress and heat to the point of fuel combustion... otherwise it will just crank and crank and never fire up.

The smoke does indicate a fuel problem... you can have your injectors checked and if needed nozzles replaced easily.

dieselgman
Title: Re: ONAN 11.5 DNAD
Post by: ronmar on July 06, 2012, 12:17:43 AM
I have always interpreted grey smoke as a fuel starved condition.  Do you have fresh fuel in it?  Moisture in the fuel can also cause grey smoke(less actual fuel in the fuel that is being injected)...  Also check your start/run solenoid and the associated linkage and the wiring to it.  If it is hanging up, that could also cause a fuel starved condition.  What type governor does this rig have?  Electric or mechanical?
Title: Re: ONAN 11.5 DNAD
Post by: dieselgman on July 06, 2012, 12:43:37 AM
Cole,

New Standyne injectors for that model are $69 each and readily available if needed.

If you can get it to run well enough, maybe some strong fuel system cleaner can help. Howe's or SeaFoam are common varieties, or if available to you, some good biodiesel will also clean things up pretty quickly.

dieselgman
Title: Re: ONAN 11.5 DNAD
Post by: mauicole on July 06, 2012, 08:17:40 PM
ronmar, There is a water separator on the fuel filter, but I better try some fresh fuel. The exhaust smells really rich, is that how it would be if there was water present? The solenoid looks like it's working properly and it has a mechanical gov.

The previous owner had no service records and claimed about a year ago he spent $2000 in repairs that repaired nothing.

I noticed there are new seals on the push rod tubes. But from what I can see of the head gasket, it looks old. Not sure if reusing and old head gasket on these is a good idea. Could this explain low compression and possibly water in the combustion chamber?

Also, the injectors were very hard to remove, nearly rusted in place.

Gary, I have yet to find anyone on island that can test my injectors. (Ahhh, the price of paradise) I suspect it's been some time since they were last serviced-if ever.

From the Alpha Series manual:

Every 6000 Hours
The previous items and give the engine a major
overhaul, if necessary.

:o
Title: Re: ONAN 11.5 DNAD
Post by: Tom on July 06, 2012, 08:29:02 PM
The smell is likely unburned fuel which is what the white smoke consisted of. You can test the injector spray pattern on the engine. Just hook up to the fuel line with it pointed in a safe direction, keep hands and body parts away from the spray and crank the engine. You should see a nice fine mist of fuel. If they are similar to my listeroid, they will make a nice metallic clank sound if you can hear it while cranking. All 3 injectors should have an identical spray pattern.
Title: Re: ONAN 11.5 DNAD
Post by: ronmar on July 06, 2012, 11:10:43 PM
I would do exactly what Tom said, with a second emphasis on the safety warnings.  Injection injuries are VERY serious and usually result in some sort of amputation, as it just simply kills the part of the body that gets injected with fuel.  Also breathing the finely atomised fuel is to be avoided at all costs...

You should be able to see a good spray pattery while cranking the engine over.  Yes, with grey smoke the exhaust should smell of unburnt fuel.  Basically the spraypattern is so sparse that the flame front cannot travel fully thru the cloud of atomised fuel, so the heat it makes just further vaporises the fuel and smokes it instead of burning it which creates great white grey smoke.  Great for fogging mosquitos and neighbors, but not so great for making torque:) 

The fact that it ignites at all tells me you probably have sufficient compression.  I can get the same symptom in two ways on my 6/1.  One way is when the hard line is not properly bled.  The injector gives a little series of popping sounds instead of a good solid single click/creak.  This dosn't deliver enough fuel to fire completely untill all the air is bled off the hardline and a full squirt of atomised fuel is delivered.  A poorly firing injector could be delivering insufficient atomised fuel to combust completely....

The second way, particularly when cold, is that the fuel rack is not all the way open. The original listers had a starter pawl on the rack.  You rotated this lever which allowed the rack to open farther for extra fuel when starting.  As soon as the engine came up to speed and the governor closed the rack, this lever rotated and prevented the rack from opening that far when running.

On a mechanical governor, the spring is trying to pull the fuel rack all the way open to the full throttle position.  Once the engine starts, it accelerates till the flyweights come up to sufficient speed and develop enough force to overcome the spring pressure and close the fuel rack.  These two forces balance at the set running RPM.  IF you have a broken spring, there is nothing to pull the rack all the way open for starting/running.  The shutdown mechanism usually adds additional force on the side of the governor to overcome the spring and cutoff the fuel to shutdown the engine.  IF this mechanism is hung up or broken it could be preventing the fuel rack from opening fully.  You say you got it to run sort of, but I bet it would fail to take any kind of load, because it is just barely getting enough fuel to be doing what it is doing.  IF your injectors have a good spray pattern, I would visit the governor and fuel rack linkages... 

Title: Re: ONAN 11.5 DNAD
Post by: mauicole on July 07, 2012, 12:43:40 AM
Tom, Gary and ronmar - thanks so much for taking the time and helping me figure this out! I drained the old fuel and replaced with fresh diesel and some Lucas injector cleaner. It started much as before but this time I ran it for 20 minutes. As time went on there was less smoke. Here is a video of the smokestack at the end of that run:

[youtube]http://www.youtube.com/watch?v=QjUVd0gne_k[/youtube]

After I shut it down I noticed a good amount of fuel had leaked out of the header! Now I beginning to believe it must be the injectors. Next I'll pull them and carefully observe the spray.

(http://listerenginegallery.com/main.php?g2_view=core.DownloadItem&g2_itemId=7123&g2_serialNumber=1)
Title: Re: ONAN 11.5 DNAD
Post by: mauicole on July 07, 2012, 03:18:56 AM
Here's the test I did. The middle injector in the video didn't spray like the rest, so I switched it with the one on the right and the middle one still didn't work. The spray on each looks pretty good and I made sure the high pressure line wasn't blocked. It looks like I have a bad injector pump.

[youtube]http://www.youtube.com/watch?v=fS-B3xMZRi4&feature=youtu.be[/youtube]
Title: Re: ONAN 11.5 DNAD
Post by: dieselgman on July 07, 2012, 03:34:03 AM
That would be a logical deduction. Check the linkage on the middle pump before replacing it. Also take a look at the cam lobe to be sure that it is providing the full lift it is supposed to.

dieselgman
Title: Re: ONAN 11.5 DNAD
Post by: listard-jp2 on July 07, 2012, 10:44:21 AM
It looks like I have a bad injector pump.

That could be expensive to overcome, as it is not possible to recondition the injector pump on the LP series of engines (due to the pump body forming the element which the pump plunger fits directly into), reconditioning of these pumps is limited to delivery valve replacement, and frankly if you have to replace this item, you may as well replace the whole pump.

Title: Re: ONAN 11.5 DNAD
Post by: ronmar on July 07, 2012, 08:17:02 PM
Here's the test I did. The middle injector in the video didn't spray like the rest, so I switched it with the one on the right and the middle one still didn't work. The spray on each looks pretty good and I made sure the high pressure line wasn't blocked. It looks like I have a bad injector pump.

Sounds like good solid troubleshooting, looks like you are on your way to an ultimate solution.
Title: Re: ONAN 11.5 DNAD
Post by: mauicole on July 11, 2012, 04:52:48 AM
Finally had some time to do more trouble shooting (big Rodeo this weekend on Maui and my wife likes horses and cowboys) :laugh: The governor linkage has a little fork that controls the pump and feels like it's doing it's job. I checked the cam lift for the middle and rear pumps. The middle one is about .006" less. Doesn't seem like enough to effect the pumps function or does it? Also, if the pump isn't working, why is there so much unburned fuel in the exhaust? (The middle exhaust manifold port was wet with diesel)
Title: Re: ONAN 11.5 DNAD
Post by: ronmar on July 12, 2012, 10:26:53 PM
At running RPM, it may be dribbling a little fuel, but not in a spray pattern that will ignite fully...
Title: Re: ONAN 11.5 DNAD
Post by: mauicole on August 02, 2012, 08:07:29 PM
I pulled the crankcase door to clean and check things out in there and to my horror the middle and rear big end bearings were shot.
Why oh why didn't I check this first? :-\ Both of them could move. The middle was the worst and the journal looks pooched.

(http://listerenginegallery.com/main.php?g2_view=core.DownloadItem&g2_itemId=7207&g2_serialNumber=1)

(http://listerenginegallery.com/main.php?g2_view=core.DownloadItem&g2_itemId=7209&g2_serialNumber=1)

 Now I wondering if its worth taking apart to see if the crank and rods are good enough for an overhaul.
Title: Re: ONAN 11.5 DNAD
Post by: dieselgman on August 03, 2012, 12:10:52 AM
Ouch!,

Seems like you would have seen low oil pressure and some extra noise there.

We have conrods available if needed... crankshafts are still available from Lister stocks as far as I am aware.

dieselgman