Oil viscosity test in generator

[D_Ville_TX]

Hello All,

Yesterday I did some experimenting with oil viscosities to see how it relates to oil temperature.

Testing was done on a Harbor Freight 3050W generator with a 6.5hp Chonda engine. All test were done at the same ambient temp (55F), and the generator loaded with two 1500W heaters.
It was running almost WOT until the oil temp had stabilized and not changed for 20 minutes before taking a reading.

I had an extra oil-fill cap for the engine, so I drilled a small hole in it and pushed a thermocouple type K through it and sealed with RTV.
All measurements are in Celsius, since that is all my indicator has.

The engine already had Mobil1 15W50 in it, so that was used for my initial test.

Test 1.
Mobil1 15W50
Runtime 30 minutes under full load. Oil temp stabilized after 10 minutes.
Measured oil temp was 96C

Test 2.
Rotella 30W
Same time conditions as test 1.
Measured temp was 94C

Test 3.
Royal Purple 10w30
Same time conditions as test 1.
Measured temp was 94C

Test 4.
Rotella 15W40
Same time conditions as test 1.
Measured temp was 95C

Conclusion is that my normal fill of Mobil1 15W40 is running slightly higher in cold weather.
In the summer we often have 100F+ temperatures, so I opt to keep using 15W40 or 15W50 for this unit.

The generator was clearly making less mechanical noise with the 15W50 oil.

The generator was running ALMOST WOT on all tests, and I did not detect any difference in RPM (3600rpm +- 20rpm) or throttle position between the oils.

Older Honda specs for this engine is:
10W30 from -5F to 90F
10W40 from -5F to 110F+
20W50 from -15F to 110F+

Any comments would be appreciated.

 

[kcfx4]

i wouldnt waste money on M1 in a sm engine, just run a 10w30 dino in your flavor, let me point out im not calling M1 a waste of money, just is in a sm engine.....my opinion

 

[QuadDriver]

not to be a party popper, but isnt this kinda like painting a car a different color to get different wind resistance?

IMO the generator flowchart should look like this:

Starts and runs? Y-> use it
N - fix it

did it explode? Y - buy a new one
N - store for next time

 

[D_Ville_TX]

The reason I did this test was because it was time to change oil in the generator, and I had partial bottles of all the tested oils.
There has also been discussions about higher viscosity potentially running hotter. This test did confirm slightly higher temp, but very marginally.

 

[kcfx4]

i respect the test, liked it, glad you took the time to do so. Heres my point as it always has been...Synthetic is a WASTE of money in a sm engine.....for years my experience has been.....
from Kohler K series (no oil filter, slinger only, piston slapping, noisy engine) to todays most quiet, fuel efficent, oil pump, and filter (kawasaki) have ran on and require sae30 in warm conditions and 10w30 in cooler conditions (most all engines) , theres a hype out there of 15w40 wich will by all means work, but still these engines have survived YEARS on 30 weight, synthetics will also work, but i know of numerous times its resulted in consumption. Truthfully speaking a sm engine will run on nearly any oil, and in a well maintained engine, its gonna way out last the machiene its on (non commercial mowers)

 

[Cujet]

I've not found that synthetics are a waste in air cooled engines. In fact, as I keep mentioning, many, many generators failed due to oil related issues after the hurricanes. My 2 Honda water pumps failed on the rated Penzoil. However, M1 15-50 solved the problem. You be the judge.

 

[kcfx4]

so are you saying this hurricane/water related? if so, thats not a usual thing in a sm engine.......

 

[Astro14]

If your generator is like mine, you really count on it when power goes out...and the last thing you want is an oil-related failure when you're running essential services with it...it's not like a lawnmower where the grass can wait until next week...

What's the capacity on this thing? 1.5 Qts? What's the price difference on synthetic vs. dino for this? 5 bucks? Less if you've got extra in your garage? Since you've shown there is little difference in performance/temp with viscosity, go with whatever synthetic you have on hand or can get on sale...

You'll have the piece of mind when the next emergency strikes and you fire it up...

 

[kcfx4]

the points not price its consumption for me and engine requirement, and i noted the OP mentioned harbor freight, i wouldnt bet the farm on anything they sell, and my OPE starts just like my cars....whenever i turn the motor over

 

[D_Ville_TX]

Consider that this test was done in a cool ambient, at least for Texas.
This engine only holds a litte over 1/2 quart, so cost is not an issue.

We have most power outages in the summer when air-conditioners are loading the grid the most, and ambient is sometimes > 100F when the generator is needed to run refrigerators and freezer plus some fans.

This generator has seen a lot of use, and never used any oil between my 75-100 hour oil changes.
I will stay with 15W40 or 15W50 since I have never had any problems, and it will not get very cold here in the winter.

 

[Bror Jace]

"Did it explode? Yes - [then] buy a new one"

I detest this attitude ... but it's pretty prevalent these days. Doesn't anyone see a positive moral component to making machines last longer? Not merely using things up and throwing them away?

Cujet has made this point about his water pumps running in the Florida heat before. Using various spec oils causes them to fail during extended runs. Mobil 1 15W-50 is the only thing that works for tens of hours at a run.

Oh, and D_ville_TX, thanks for doing this test. I would have expected a slightly bigger difference ... but it's kinda hard to argue with what you've measured here.

 

[kcfx4]

but bror, you cant rule out moisture, something most sm engines dont deal w

 

[D_Ville_TX]

I also need to point out that the 15W50 test was done with the oil that had been in the generator for 75 hours, while the other tests were done with new oil.

Don't know if this would impact the results.

 

[dakota99]

Thanks for doing this test! I've always wondered what temp the oil runs in small engines such as these.

It might be more work and cost more, but it would be cool if you re-did the test when the temperature was another extreme like 85F-90F or 15F-20F. Just to see how ambient temperature affects the internal temp.

 

[D_Ville_TX]

dakota99

We hardly never see 15F-20F here, so I can not test in low ambient. I might re-test when we get 90F-100F+ here as that happens several months every year.

I would expect that the higher viscosity oils I used for the test would not do very well in low temperatures.

I do believe they do very well in higher ambient temperatures.

 

[QuadDriver]

Originally Posted By: Bror Jace
"Did it explode? Yes - [then] buy a new one"

I detest this attitude ... but it's pretty prevalent these days. Doesn't anyone see a positive moral component to making machines last longer? Not merely using things up and throwing them away?

Cujet has made this point about his water pumps running in the Florida heat before. Using various spec oils causes them to fail during extended runs. Mobil 1 15W-50 is the only thing that works for tens of hours at a run.

Oh, and D_ville_TX, thanks for doing this test. I would have expected a slightly bigger difference ... but it's kinda hard to argue with what you've measured here.


what additude? engines, just do not fail anymore due to oil related issues. as you are aware from the discussions we had over 6 years ago, almost no one has ever experienced an oil related failure. 'lackofoil' related failure perhaps, but never due to the oil (and even then it was likely due to the oil being 10 years old). power equipment engines failing during long usage? did anyone bother to CHECK the oil? power equipment engines consume the crankcase blowby gases into the carb. which is prolly why they ALL say 'check oil before each use'. that should include fuel ups.

in 2003 when the tornado knocked over the kinzua bridge, I powered my whole place for 8 straight days on a 5000w genset. First off, is it likely anyone here has ever done that? no. what did I find every fuel tank? the engine, with no outward signs of consumption, consumed oil. to the point where is was significantly below the low mark on the stick, yet never tripped the low oil protection. so much for preconceived notions of how stuff works eh?

my grandfather used to run his 1960 B&s 2.5hp laydown mower on the USED engine oil from his 70 caprice and 75 impala. How good was THAT oil? how good was THAT engine?

If you think there are too many failures today, look no farther than the fact that it is likely cheap chinese [censored] and an engine with a crankcase casting half the thickness of its american ancestor just might not last as long regardless what you put in it

 

[JTK]

Originally Posted By: D_Ville_TX
Hello All,

Yesterday I did some experimenting with oil viscosities to see how it relates to oil temperature.




Good info! Thanks for taking the time. I too think synthetic has its place for extremes in operating conditions (which a portable generator might see), but for normal conditions, it's basically the same as running a $2 conventional.

Regardless, it's great info!

Joel

 

[JimPghPA]

D-Ville, thank you for doing that test and posting the results.

I keep GC in my Coleman Powermate 5000/6250 Watt generator with 10 HP HM-100 Tecumseh engine. And also keep two quarts of M1 Vtwin 15W-50 for use on very hot days. I had some concern that the M1 might significantly increase the running temperature of the oil/and inside of engine. Your test shows that is not the case.

Thanks.

 

[JimPghPA]

BTW, during a major power outage is no time to go looking for a new gen-set to replace one that blew because you saved two cents on a cheap oil. If you look for a gen-set in a major outage, the chances are that all the stores will be out of them, if they can even open the doors. And the only way to get one would be to get in your vehicle and drive for hours in the best direction of large hardware stores that did not get part of the major weather that caused the outage. And when you do find one it may be much biger or smaller than you want.

 

[JimPghPA]

M1 Vtwin is 20W-50.