Bob from Beaver County Show full post »
Peddler
What engine was that and was it stock?
Quote
Cobranut
Peddler wrote:
What engine was that and was it stock?


It's a Yamaha XJ-1200 bike engine.  Balanced and blueprinted but otherwise stock.
The oil also lubricates the transmission and clutch.  The gears tend to shear down the oil, which makes it one of the toughest applications for motor oil.
Quote
Peddler
I'll bet you change the oil after every race, we certainly did when I was racing.  If you changed the oil in a 2.4 running at 3600 RPMs every 24 hours you wouldn't have any oil consumption either. In 24 hours that 2.4 has turned almost twice as many revolutions as your Yamaha has at 8,000 RPMs for 5 hours and it is not a racing engine by design.  I have watched many of these units through long runs and they do fine for a couple days and then start going through oil quickly.
Quote
Cobranut
Peddler wrote:
I'll bet you change the oil after every race, we certainly did when I was racing.  If you changed the oil in a 2.4 running at 3600 RPMs every 24 hours you wouldn't have any oil consumption either. In 24 hours that 2.4 has turned almost twice as many revolutions as your Yamaha has at 8,000 RPMs for 5 hours and it is not a racing engine by design.  I have watched many of these units through long runs and they do fine for a couple days and then start going through oil quickly.


Yes, with those oil temperatures I changed it every race weekend. 
We run one  practice, one qualifying session and one race per day. 
Quote
W. Isaac Burkwalt UnionSchnauzerLocal1
I had a similar problem with a 60KW. The unit would run for 3-4 days during the winter and it would shut down on low oil. The pad would be covered in oil. The main thought was it was the crankcase would build up pressure and blow it out. I learned of this condition after the third time. I did a compression test and a cylinder leak down test. Well within the specs. The exhaust blanket had an oily feel to it and it would smoke. I cleaned the engine and pad and ran the unit for several hours in the hot sun with no leaks detected. The owner was becoming concerned with the time I was investing in it (a couple of days) so I backed away from it at his request. I did see it was a newer serial number as the older units had a kit for the crankcase pressure. This unit had all those parts on it. About 6 months or so rolled by and the owner called me. It would not start. I found no oil on the stick. I filled it and the starter could not roll the engine over. Number 3 cylinder was all but seized. I installed a new engine. So far so good. The customer is a fire station that checks the equipment once a week. I asked why he did not do the generator as well. Should not have to was his response. I asked why do they bother installing dip sticks on the fire trucks? He did not know but his township board instructed him to make it his job and they wanted to see the weekly log. Just because it has a low oil cut off does not mean you should use it rather than checking it out once a week. By the way, I was thinking the oil was coming from the transition of the dip stick tube from the oil pan to the actually tube. This unit was loose and you could find oil there like it was working its way out. That was before I was told to hold off. Not sure, but a dollar o ring may have made some difference. I am also certain 3600 RPM is gonna consume some oil as well over extended run times. When I took it apart, I did find a little oil resting in the bottom of the intercooler. So turbo blow by may be another area it will loose some oil. 

isaac
Quote
W. Isaac Burkwalt UnionSchnauzerLocal1
Follow up. Doing more research on the issues with this customers 60KW I came across what I think may have been the problem all along. Wet stacking. My father spoke of this during his years as a diesel mechanic. I never knew it is also a condition with generators. Makes perfect sense. The generator is question was purchased with a grant. The master plan was a new fire station, public library, and township hall with space for the village street equipment. The generator was sized for this much larger load that has yet to materialize. Denied grant requests and failed bond proposals has left this generator doing the work that a 20KW air cooled unit could easily handle. So the engine is simply not getting hot enough doing run times to expand the rings and seal the unit. So we get what we see. Oil coming out of the exhaust, elevated crankcase pressures, and a dissatisfied customer. Friday I installed the extreme cold weather kit on the unit (both the block coolant heater and the battery blanket) and performed a three hour load bank test on it. Let it run about 15 minutes checking for leaks in the coolant system then working it up to 25KW load for the next half hour. Then stuck 50KW to for the next hour and 45 minutes then easing it to no load for the next 15 minutes. The unit ran like a rock star with absolutely no issues. Generac recommended at about 80% load, the load bank I was using stepped in 5KW increments. Close enough. I try not to abuse the Generac tech line as we were warned in class to do our due diligence to solve problems via the flow charts. Since this issue was not specifically addressed I spoke to a nice guy who didn't seem to read from the screen but had a great conversation regarding my problem and concurred with the theory of wet stacking based on the facts present, little load, oil consumption by exhaust discharge, and crankcase pressure pushing the dipstick an inch or so out of the tube. The oil is now a dark color instead of the normal Mobil 1 golden clear that I usually see. Now I wait and see. The Generac guy said I will use a quart of oil every 24 hours of constant run. Just the nature of this beast. However, this should solve the problems short term. Long term I need to either install a load bank on the generator until the large loads come or I will at least once a year do another load bank test. Maybe even twice a year. After 30 years of electrical work, I am enjoying the fact that I am still learning and gaining wisdom. Hopefully I'll make the customer feel better that I am attempting to solve his concerns and restore his faith in Generac. Generac makes a great product and has great resources to make this product serve his needs for a long time.  
Quote
Peddler
Good information for all of us!
Quote
78buckshot
Getting back to Beaver Bob, his is not susceptible to wet stacking as it is natural gas fired.
Quote
W. Isaac Burkwalt UnionSchnauzerLocal1
Sure it is. The unit I am working on is LP fired. 
Quote
78buckshot
 If it is getting LIQUID propane in the generator or even past the secondary LP regulator then we need to back up and diagnose the LP system. The engine is designed to run on gaseous fuel - either natural gas or propane in a VAPOR form - not liquid. The LP changes state from a liquid to a vapor when it passes through the primary and secondary regulators, by the time it reaches the demand regulator and the intake system of the engine it is or should be a vapor or gas with no liquid. Please take this as intended - we are trying to help.
Quote
W. Isaac Burkwalt UnionSchnauzerLocal1
Haha. While wet stacking in the diesel world got it name from raw fuel oozing out the stacks wet stacking in the generator world is engine oil oozing out the exhaust. Google it. In my case, I was not getting fuel out of the exhaust. Just excessive oil use. The unit in question was both burning it, pushing it out the exhaust, and pushing it out of the dip stick. I am also trying to help as I learn I am sharing. This is also the diagnosis from Generac as to my problem.  
Quote
78buckshot
I understand the issue in a underloaded diesel, I have some experience - from a D9 Caterpillar (1470 cu. in. 6 cyl ) to OTR class 8 (Cummins, Cat, Detroit ) to city delivery ( Cat, Detroit, IH ) to my little 6.5, please school me on how you conclude the LP fuel is the culprit.
Sure it is. The unit I am working on is LP fired. 
Quote
W. Isaac Burkwalt UnionSchnauzerLocal1
The fuel is not the culprit nor did I say it was. All I am saying is a generator can get a problem called wet stacking due to being in my case grossly oversized. Engine is not working hard enough to generate enough heat to 'seal itself'. Then the excessive oil use wether burning it or pushing it out the exhaust or seals or even all the above happens. What I meant was when you stated Beaver Bobs problem can't be that since it is NG fired is not true. While that may not be his specific problem, it is mine. Wet stacking in a generator does not mean it has to be a diesel driven prime mover. It can happen with gaseous units as well. 
Quote
78buckshot
Thank you for making that more understandable. Are you a UA Local 1 member? East Coast?
Quote
W. Isaac Burkwalt UnionSchnauzerLocal1
No problem sir. Perhaps I could have been more attentive in creative writing classes. 🙂 Wet stacking is almost always a diesel set but it is loosely used with the gaseous units. I am an union man, IBEW Local 445. Michigan. You? 
Quote
Cobranut
I've only ever heard the term wet-stacking associated with diesels.
Even a fully broken-in diesel, when operated with light loads, can glaze the cylinder bores to the point where the rings no longer seal.
It can often be remedied by running under a heavy load, but I've heard that sometimes it will never seal up again, and requires a teardown, honing the cylinders and new rings.

It sounds like this issue is related to the fact that it never had enough load to seat the rings when new, and now the cylinders have become glazed and no longer have enough crosshatch to seal the rings properly.

Most people are under the impression that an engine should be babied diuring the break-in period, when the opposite is actually true.
Run it long enough to get everything up to operating temp, and make sure there are no leaks or other problems, then put a load on it and run it hard enough to seat the rings properly.

The 27kW maximum tankless electric water heater in my home ensures my 30kW diesel sees enough heavy loads to hopefully prevent this problem.
My wife managed to trip it on overload once.  I had the heat and lights in my shop running, and she had two washers and a dryer going, the oven on, the heat pump on, and turned on the hot water to fill the sink.
I had to explain to her that the genset could run anything in the house, but not EVERYTHING in the house.  LOL
Quote
W. Isaac Burkwalt UnionSchnauzerLocal1
LOL. That is exactly what happened to this poor generator. Out of the box with virtually no load. I replaced the engine last summer and ran the unit at the shop for several hour without loading it. That is my mistake. I thought just like you said, I need to baby it and the little documentation that came along with the motor never made me the wiser. Now I know. This reminds me of my car salesmen. In late summer of 2002 I found a '02 SS/Z28 sitting shinny new on the dealer showroom. Triple black convertible with some SLP Performance upgrades. I purchased that car. The salesman warned me. He said I know your a Harley rider (I am with two hogs and an Indian, my preferred method of travel) and you are gonna mothball this car. Before you do, put at least 600 miles on it at or above 70mph. And do so for a couple of hours or more straight. I did and I never have any issues with this car. It now has just over 5,100 miles on it. Back to generators, some customers use the bigger is better mentality. Wanting to be ready for futures needs. But considerations need to be taken like radiator mounted load banks to ensure the rings seal and stay that way. Or get a 27KW tankless heater and a toaster. 🙂

isaac
Quote
78buckshot
Well Isaac, we are dang near neighbors, I'm Plumber/Pipefitters/Gas Distribution/HVAC Local 190, Ann Arbor. Our hall is shared with IBEW Local 252. Have a good and safe day in the weather.
Quote
W. Isaac Burkwalt UnionSchnauzerLocal1
I'll be lurking around the Taubman Center this Friday. Follow up appointment for being a living organ donor. Right in the heart of your playground. I love that place. I'm humbled by the work they do there.
Quote
78buckshot
I was born in the U of M hospital, the current football team Dr. did my rotator cuff repair a couple of years ago. We do a little work for the U, a number of our members are employed directly by the U of M, plumbers/fitters and HVAC. As a kid we used the campus as our playgrounds, we could get into the BIG HOUSE and ride our bikes around inside the stadium. Now they keep it locked up tighter than a drum. Things are a little different than they were in the 60's.
Quote