Air filter oil viscosity

[Merkava_4]

On those Briggs & Stratton foam air filters, which weight oil do you guys prefer to oil them with?
I've been using either HD30, 10W-30, or 10W-40 and it doesn't seem to make a major difference
in the way the engine runs, but I thought I'd ask you guys anyway just in case. I try to squeeze
most of the oil out of there and just leave a film.

[NO0C]

I don't know how viscosity would enter into the equation.

I'm sure 80W90 would work just as well.

Years and years ago when working in a service station when using canned, yes canned oil, we had a gizmo on the wall that we would let the cans drain into after pouring most of the oil in the car's engine during a change. The drippings (mixed viscosities) are what we used for servicing oil bath air cleaners.

[Merkava_4]

I don't know how viscosity would enter into the equation.

If the oil is too thick, it will hinder the flow of air through the filter.

If the oil is too thin, it won't collect the dust particles.

[HondaG100]

Use the same oil as you use in the crank case.

[JonCraig]

My newer Briggs say, "use no oil". I assume that's EPA junk, so I oil them anyway. (Note I'm talking the pre-cleaner; not the paper air filter itself.) I use cheapo 3-in-1 oil, have been for years, and it seems to work fine. It's my understanding that the oil is just there to get the foam "sticky". I would think any viscosity at all would do the job adequately. And my guess is that it takes *far* less oil to do the job than what most people put on. I try to wring mine out really, really well, to the point that it just barely leaves a "film" on my hands, rather than making an oily mess.

My $0.02.

--JC

[bgsengine]

My newer Briggs say, "use no oil". I assume that's EPA junk, so I oil them anyway. (Note I'm talking the pre-cleaner; not the paper air filter itself.) I use cheapo 3-in-1 oil, have been for years, and it seems to work fine. It's my understanding that the oil is just there to get the foam "sticky". I would think any viscosity at all would do the job adequately. And my guess is that it takes *far* less oil to do the job than what most people put on. I try to wring mine out really, really well, to the point that it just barely leaves a "film" on my hands, rather than making an oily mess.

My $0.02.

--JC

the ones that say "use no oil" are because the pre-filter is directly up against the paper element and oil from the filter will contaminate the paper element. The ones that you do oil usually have a mesh , or they are in contact with the expanded metal outer casing of the paper element , so there is no direct contact with the oiled foam and the paper element.

yes most any oil will work (We use drippings from drained oil bottles so we get a mix of anything between 80W90 and 5W30 synthetic) but generally supposed to use the same oil you use in the crankcase - your thoughts are correct that the oil is just to moisten the foam (fills the porous gaps of the filter to trap dirt and dust that passes through) and if correctly oiled, won't affect air flow - We've even used bar oil - (high tack, no sling, very sticky) - no problems when correctly oiled .

Failing to oil a filter that is designed to be oiled results in the filter actually passing dirt through to the intake.

[Merkava_4]

bgsengine,

Which chemical do you prefer using to clean the foam air filters?

I've been using straight Purple Power and although is works very well,
it seems to be harsh on the foam material. What I need is some kind
of water soluble cleaner that's a little easier on the foam.

[Mek-a-nik]

I replace all but the nicest foam filters. Cheaper than the time spent cleaning an old one that may be no good anyway after cleaning and inspection.
I've seen some that have so much oil in them that I'm surprised that they run.
I use 30wt that I have in a pump can.

My boss from a gas station job I had in the 70's used the drain oil from customers cars to top off his 61 GMC panel truck. No, he never changed it, and yes, it was a piece of junk! But it always ran.

[NO0C]

I have always done what B&S says:

1. Wash foam in liquid detergent and water. (Dawn does a great job)
2. Squeeze dry in a clean cloth.
3. Saturate foam in engine oil. Squeeze in clean cloth to remove ALL excess oil.

(From O&M Instructions for 92500 series engines).

[acscolo]

"I replace all but the nicest foam filters. Cheaper than the time spent cleaning an old one that may be no good anyway after cleaning and inspection.
I've seen some that have so much oil in them that I'm surprised that they run."

Yep my feeling exactly