Note: Our typical camping climate range runs from 10F to 115F (if we go to Redding, CA in the summer... otherwise up to about 105 in Southern Oregon.)Clearly Onan/Cummins have updated their recommendations for the old BFA. Whereas they once recommended 30W only, they now have a chart with several recommendations for different temp ranges with a nod to 15W-40 (I'm currently using) for the widest ranges. But no mention of 20W-50. And my searches (though they do show some guys running 20W-50 with no problems and some with) turn up little mention either. Why?Now I know that 20W-50 is not a perfect 20 nor a perfect 50 for their prospective temp ratings, but it still seems that if 30W worked back in the day, that 20W at cold temps is better than 30W and 50W on a hot day is better than 30W.The only thing that I can reckon is that a good 30W is... pretty much always a 30W and doesn't break down to anything less. But that shouldn't be an issue to anyone who changes their multi-weight oil often enough.Now theoretically, other than the potential for thermal breakdown in time or overheating, a 10W-30 should act the same as a straight 30 at 212F. So why the difference in the chart below?The reason I even ask is I run 20W-50 in the 454 (another conversation) and I wouldn't mind just keeping one spare oil type aboard.The only other thing I can figure is that Onan would prefer the lower resistance for the little 2 banger to better lubrication. When I get a chance... I'll ask 'em.Your thoughts?.

Your logic sounds good to me.However, if you call Onan, IMO the chances of getting an actual Onan engineer to commit to a debate on the pros and cons of using 30w vs. 20w-50 is highly unlikely. More than likely you'll never get farther than the typical technical support rep who doesn't have the necessary engineering background to authorize a deviation from the guidelines established in the owner's manual.If your Onan is under warranty and you're operating in ambient temps above 100 degrees, 30w is the only way to go---if you want to keep your warranty intact. If your Onan is not under warranty, and you're willing to take the risk, then give 20w-50 a try. If it doesn't sieze or blow-up, get an oil analysis and go from there.

There was a similar post just a few days ago about generators and Sprinter oil. It occurred to me then and does now, also, how much oil of a different weight is needed for the generator? My guess is a quart or less.

My thought for the higher side of the temperatures you mention, the 20W50 is fine. At 10 degrees it may be a little heavy. If it cranks over and starts OK you're good.

Have you tried the 20W-50 in your onan yet? I tried a multi-weight oil in my Emerald 3 6.5 once and found that it burned through way too much oil. I do not recall which multi-weight oil I tried, however, and I did try it during the summer.Miles

Son of Norway wrote:Have you tried the 20W-50 in your onan yet? I tried a multi-weight oil in my Emerald 3 6.5 once and found that it burned through way too much oil. I do not recall which multi-weight oil I tried, however, and I did try it during the summer.MilesNo.Been using 15W-40 for the last several years. I can say that she does burn through a bit of oil, but I can't recall whether or not she did with just straight 30.Overall she runs well. But when it's hot, if I shudder' down for a bit, she won't exactly clamor at the thought of starting up again. Though she will fire up again eventually. But that was the case with straight 30 too.It's important to keep in mind that she'll run the overhead A/C for hours with the mercury up and over a hundred and only stop when I hit the kill switch.

Onan BFA Oil - Why not 20W-50? | Good Sam Community

udidwht
Explorer
Jun 07, 2018
KendallP wrote:
MEXICOWANDERER wrote:

...The laugh is earlier VW engines had a chicken wire screen "filter?" A real chew & spit arrangement...

Pretty sure my '73 Super B had one of those. Think I performed an LOF about every 2K on that one. We had a lube pit at Pops' ranch growing up.

Of course I paid attention to the valve intervals as well.

I flat drove the wheels off that thing. Practiced my rally-style power braking all over the fire and logging roads for years. I could make her do anything I wanted.

Sold her with well over a hundred K on the original and she showed no signs of wearing down yet.

In a weak attempt to remain somewhat on topic...

I would bet it was Castrol 20W-50 in that rig too. We bought it by the case for the shop.

That was the Type-1 engine. The Type-4 motor was miles ahead of the Type-1 in terms or reliability and longevity. No internals from the T-1 were compatible with the Type-4.

The Type-4 was used in the VW T-3 Squareback & 411, 914 Porsche and the 1972 - 1979 VW buses.
udidwht
Explorer
Jun 07, 2018
MEXICOWANDERER wrote:
Air cooled engines love ashless motor oil. Aeroshell 60 would make an excellent air cooled engine oil. A 4-place aircraft finds it difficult to pull over and cll Good Sam.

I would not recommend oil designed for aircraft engines in vehicles with an air-cooled engine. Aircraft operate in completely different parameters than cars.

One of the best air-cooled oils for an air-cooled vehicle is Brad Penn. It is the original Kendall motor oil when it was green. Another outstanding oil for air-cooled engines is Valvoline VR-1 Racing oil (Dino version). I use the Valvoline VR-1 in both my 72 VW Camper and my RV.

As for oil filters:

1. Mobil 1 Extended Performance filter (Best)
2. WIX
3. Napa Gold
coolbreeze01
Explorer
Aug 20, 2016
O.K. :C
KendallP
Explorer
Aug 20, 2016
MEXICOWANDERER wrote:

...The laugh is earlier VW engines had a chicken wire screen "filter?" A real chew & spit arrangement...

Pretty sure my '73 Super B had one of those. Think I performed an LOF about every 2K on that one. We had a lube pit at Pops' ranch growing up.

Of course I paid attention to the valve intervals as well.

I flat drove the wheels off that thing. Practiced my rally-style power braking all over the fire and logging roads for years. I could make her do anything I wanted.

Sold her with well over a hundred K on the original and she showed no signs of wearing down yet.

In a weak attempt to remain somewhat on topic...

I would bet it was Castrol 20W-50 in that rig too. We bought it by the case for the shop.
MEXICOWANDERER
Explorer
Aug 20, 2016
On the Kubota

Luberfiner C-750L

On the Lomardini

Zip

Just the spin on. Meaning a lot oftener oil changes

Agreed. The low micron number bypass filter is an absolute winner.

The laugh is earlier VW engines had a chicken wire screen "filter?" A real chew & spit arrangement. Maintenance right up there with the Yugo and Renault Dauphine. All they were lacking was Lucas electrical to have been the epitome of shank's mare delight.
Ductape
Explorer
Aug 20, 2016
Mex, you using any bypass filtration? On our fleet we found it to be an economic win.
MEXICOWANDERER
Explorer
Aug 20, 2016
I prefer much longer-lived water cooled engines. John Muir made a good chunk of income publishing The Compleat Guide For Idiots - How To keep Your VW alive. $ per kWh no other engine is as economical for generators as a 12-turn (1,200 RPM) 4-cycle water cooled diesel. The Schickelgruuber lawnmower is dead and buried for a good reason. A water cooled engine of the same pounds per hour gasoline consumption can run circles around the finned VW then fart in it's face. Water cooled internal combustion engines are quieter, more economical and live longer. I used to laugh my butt off down here. Lazy gringos - dusty roads. overheated engines sitting on a mechanic's bench, cases split liners, pistons, bearings, valves and seats - all because the cooling fins weren't blasted with water weekly.
wolfe10
Explorer
Aug 20, 2016
udidwht wrote:

Want long life out of an air-cooled engine? Nothing is better than the Type-4 engine.

Are you referring to oil, or the Type 4 VW air cooled engine???
udidwht
Explorer
Aug 20, 2016
MEXICOWANDERER wrote:
Clean oil is my concern. Engine well within HC and CO emission specs. If you check the lifespan expectancy between air cooled and water cooled generator engines you'd remember it. Air cooled engines are much more fragile. I have seen a number of 37-hp Wisconsin engines running with 300+F lube oil.

Want long life out of an air-cooled engine? Nothing is better than the Type-4 engine.
Chum_lee
Explorer
Aug 19, 2016
"Sure seems like there ought to be more conclusive oil testing data somewhere."

There is. Unfortunately its proprietary and not given away to the general public freely. I have to agree much of the data (although very repetitive) in the referenced link by 540 RAT though. The ICP (Inductive Coupled Plasma) oil analysis tests thought so highly of at BITXXXG aren't worth much and there's no point in trying to explain that to BITXXXGers or anyone else without several years of chemistry under their belt.

Onan doesn't manufacture/blend oil. Onan manufactures generators. Any lubricants with the "Onan" name on the container are manufactured/blended by others, marked up and sold under the "Onan" label. If you meet/match/exceed the API specs on the Onan label, use the proper viscosity based on operating temperature, and change the oil regularly based on environmental conditions, you'll be fine. It's not rocket science but it sure gets a lot of press.

Chum lee