Oil changes -natural gas engine

[Chris_J]

Hi all,

I have what might be a dumb question but maybe not.

I have a 10kw portable generator I built that I store in a conditioned crawl space. It runs on natural gas using a B&S 570 vtwin with spin on filter. The engine was built by B&S for natural gas, it's not a conversion.

I've got Mobil 1 extended performance in it, I think 5w30.

My question is under these conditions is it still necessary to change the oil once a year even though it's got maybe an hour of run time on it from exercise? There's very little moisture, no soot and no gasoline running into the oil in this situation.


The oil literally smells new. No signs of moisture etc but I have no idea if the oil is oxidized etc from just time.

 

[Schandyman]

My friend has a natural gas generac with a Briggs vtwin he buys a maintenance kits every 2 years.

 

[WobblyElvis]

If you only use the generator a few hours a year, I wouldn't change it in less than 5 years. I do the same with my lawn mower and it's 30 years old.

 

[40w8]

If you only use the generator a few hours a year, I wouldn't change it in less than 5 years. I do the same with my lawn mower and it's 30 years old.

I ran my Mazda RX8 on Mobil 1 0w40, and changed it in 7 years and 7700 miles with a UOA. Oil thickened slightly to a more robust 40 weight while 0w40 starts as a light 40 weight. Clean natural gas is much easier than gasoline on engines.

 

[wpod]

Nat gas is a dry gas with no fuel dilution and no oil washdown on the cyl and virtually no soot. The oil lasts a long time. Conservatively double that of gasoline.

 

[jkasch]

I have a natural gas 16KW Generac. It does a weekly exercise cycle of 5 minutes. I find that if I don’t run it occasionally for longer times in the winter, the oil will accumulate condensation and get milky. I wish there was a way to program a longer exercise cycle. No option in the menu, though.

 

[Schandyman]

I have a natural gas 16KW Generac. It does a weekly exercise cycle of 5 minutes. I find that if I don’t run it occasionally for longer times in the winter, the oil will accumulate condensation and get milky. I wish there was a way to program a longer exercise cycle. No option in the menu, though.

You could try installing a crankcase or engine block heater.

 

[dlundblad]

I have a natural gas 16KW Generac. It does a weekly exercise cycle of 5 minutes. I find that if I don’t run it occasionally for longer times in the winter, the oil will accumulate condensation and get milky. I wish there was a way to program a longer exercise cycle. No option in the menu, though.

No there is not. I actually turned mine to 5 minutes bi weekly to cut down on starts. No idea if it helps.

I have the same model as you. It just runs on propane.

 

[BMWTurboDzl]

Nat gas is a dry gas with no fuel dilution and no oil washdown on the cyl and virtually no soot. The oil lasts a long time. Conservatively double that of gasoline.

+1

 

[wag123]

Even though natural gas and propane burn very clean, cold starts will cause the oil to become contaminated with unburned malodorant over time (applies to propane as well). Changing the oil once a year is cheap insurance. Over a long time period, cold starts will also cause unburned malodorant to deposit and build-up in the intake manifold/tract. These deposits need to be manually removed.

 

[Chris_J]

Even though natural gas and propane burn very clean, cold starts will cause the oil to become contaminated with unburned malodorant over time (applies to propane as well). Changing the oil once a year is cheap insurance. Over a long time period, cold starts will also cause unburned malodorant to deposit and build-up in the intake manifold/tract. These deposits need to be manually removed.

What about under the conditions where the engine is only started once per year and run under a decent load for 30 minutes?

That's closer to what my situation is unless I actually end up using the generator which then it would usually have 1 start and then however many hours.


I was originally going to build a thing so mine would be outside like a normal setup but I felt being stored inside was much better for it albeit a much bigger pain to deal with.

 

[wag123]

What about under the conditions where the engine is only started once per year and run under a decent load for 30 minutes?

That's closer to what my situation is unless I actually end up using the generator which then it would usually have 1 start and then however many hours.


I was originally going to build a thing so mine would be outside like a normal setup but I felt being stored inside was much better for it albeit a much bigger pain to deal with.

In your specific case, being a portable generator and not running it unless it is needed for use in an emergency, I wouldn't worry about changing the oil every year. I was aiming my advice at those who have a fixed generator installation (like a Generac) that goes through routine exercises on a regular basis. Also, since you are likely to run it for an extended length of time when you need to use it, I wouldn't worry about unburned malodorant oil contamination since this won't occur after the engine is hot, it is primarily during the first few running minutes after a cold start that this occurs.

 

[Schandyman]

I would just pick 2 days out of the year mark it on the calendar and simulate a power outage. Flip the main off let the genset do its thing for 2 or 3 hrs take the fam out to dinner.

 

[JTK]

I have a natural gas 16KW Generac. It does a weekly exercise cycle of 5 minutes. I find that if I don’t run it occasionally for longer times in the winter, the oil will accumulate condensation and get milky. I wish there was a way to program a longer exercise cycle. No option in the menu, though.

I've read of generacs building up enough water/ice in the air cleaner housings where the breather hose dumps into it, to cause issues. Mostly a cold weather problem. I know it's nice to know if these things are going to run, but I wouldn't have them do their auto exercise in the winter months.

 

[Chris_J]

I would just pick 2 days out of the year mark it on the calendar and simulate a power outage. Flip the main off let the genset do its thing for 2 or 3 hrs take the fam out to dinner.

Why take the fam out for dinner?

 

[Chris_J]

I've read of generacs building up enough water/ice in the air cleaner housings where the breather hose dumps into it, to cause issues. Mostly a cold weather problem. I know it's nice to know if these things are going to run, but I wouldn't have them do their auto exercise in the winter months.

I would be concerned with not exercising a unit installed outdoors especially in the winter. It's exposed to a lot of temperature changes and moisture sitting out there.

They aren't just making sure it runs.

 

[jkasch]

No there is not. I actually turned mine to 5 minutes bi weekly to cut down on starts. No idea if it helps.

I have the same model as you. It just runs on propane.

My thought is it needs to run for 20 minutes or so to get hot enough to cause the moisture to evaporate. Same as a car that only gets short trips. It needs a long run occasionally.

 

[dlundblad]

My thought is it needs to run for 20 minutes or so to get hot enough to cause the moisture to evaporate. Same as a car that only gets short trips. It needs a long run occasionally.

I wish I set it for 20 mins every month. Same runtime/ fuel use as the basic 5 min/ week. Less cold starts and short runs.

 

[dlundblad]

I would be concerned with not exercising a unit installed outdoors especially in the winter. It's exposed to a lot of temperature changes and moisture sitting out there.

They aren't just making sure it runs.

They do make battery and oil filter heaters. They are warm to the touch in the cold. I’ve never had any issues with mine not starting or having extended crank times in -teens (*F).

Fun fact: the battery heater costs more than an AGM from generac. The AGM does not need a heater.

 

[Schandyman]

Why take the fam out for dinner?

Family time is valuable. Why hang around watching a generator run