Oiling the foam...

[deeter16317]

I bought a piece of equipment whose owner's manual spells out oiling that foam prefilter...most time that's not indicated and they are left dry. I had a case of foam filter oil from way back when I owned a TruFlo filter for a car...it seemed to fit the bill, although the manual states motor oil.

So, how many of you actually oil the foam prefilter on you equipment?

 

[jds14]

I oil the pre filter everytime I service the air filter. I use a spray on filter oil that can be purchased at a motorcycle shop/dealer. Its very "tacky" so it stays put making it less messy to deal with. If it'll keep dust out of a dirt bike engine I figure It'll do for the mower too.

 

[lexus114]

If your talking about the pre foam filter that goes over the paper filter, Dont do it! I did this on my Cub Cadet pre foam filter, and it got on the paper filter too. What a mess, an I didnt even use much oil.

 

[The motor guy]

Your supposed to squeeze the oil out of it. Put a small amount of oil on. Like a 3 teaspoons and then squeeze it up into a ball with your hands to spread it around. Then you can take a paper towel and squeeze the filter with the paper towel to get the excess oil off that way it is just damp with oil.

 

[deeter16317]

Originally Posted By: jds14
I use a spray on filter oil that can be purchased at a motorcycle shop/dealer. Its very "tacky" so it stays put making it less messy to deal with.


This is similar to the filter oil I have...except mine is in a small bottle. I figured using actual foam filter oil was probably better than motor oil. The filter oil I have is an Amsoil product I got from eBay many years ago...I probably have a lifetime supply, probably go with a motorcycle filter oil from a local source next time.


Originally Posted By: motor_oil_madman
Your supposed to squeeze the oil out of it. Put a small amount of oil on. Like a 3 teaspoons and then squeeze it up into a ball with your hands to spread it around. Then you can take a paper towel and squeeze the filter with the paper towel to get the excess oil off that way it is just damp with oil.


The filter I have didn't even take that much oil...maybe a teaspoon, and it was saturated. I'm not sure a small amount of oil on the paper filter would hurt anything? I simply squeezed the foam filter to unload all the free oil (which wasn't much in my case) dripped out.

 

[boraticus]

You don't oil the foam pre-filter that covers a paper filter. The filtration system doesn't work like that. Paper filter systems are to be kept completely dry.

 

[deeter16317]

Hate to tell you otherwise, but my Grasshopper manual and the Kohler manual for the 25HP Kohler Command states otherwise.

Here's the clip from the Kohler manual for my buddy's Kohler 25HP Courage:


"Air cleaner systems used on these engines will be either the standard size or PRO Series increased capacity (slightly taller) design. Each system uses a replaceable, high-density paper air cleaner element. Some are also equipped with an oiled-foam precleaner, which surrounds the paper element."

"If so equipped, wash and reoil the precleaner every 25 hours. Replace the precleaner annually or every 100 hours."

 

[boraticus]

Originally Posted By: deeter16317
Hate to tell you otherwise, but my Grasshopper manual and the Kohler manual for the 25HP Kohler Command states otherwise.

Here's the clip from the Kohler manual for my buddy's Kohler 25HP Courage:


"Air cleaner systems used on these engines will be either the standard size or PRO Series increased capacity (slightly taller) design. Each system uses a replaceable, high-density paper air cleaner element. Some are also equipped with an oiled-foam precleaner, which surrounds the paper element."

"If so equipped, wash and reoil the precleaner every 25 hours. Replace the precleaner annually or every 100 hours."


I own a number of engines with paper elements. A Kawasaki powered riding mower, a Honda powered riding mower, and Honda Valkyrie motorcycle all with foam pre-filters. Not one of them had any trace of oil on the foam pre-filter when bought new. However, after reviewing the manual for the Honda GXV530, I see that it does recommend lightly oiling the foam pre-filter.

I stand corrected!

Here's what the Honda GXV530 (riding mower) manual says:

"Paper air filter element: Tap the filter element several times on a hard surface to remove dirt, or blow compressed air [not exceeding 207 kPa (2.1 kgf/cm , 30 psi)] through the filter element from the inside. Never try to brush off dirt; brushing will force dirt into the fibers.

Foam air filter element: Clean in warm soapy water, rinse, and allow to dry thoroughly. Or clean in non-flammable solvent and allow to dry. Dip the filter element in clean engine oil, then squeeze out all excess oil. The engine will smoke when started if too much oil is left in the foam.

Excess oil will restrict air flow through the foam filter element and may transfer to the paper filter element, soaking and clogging it."

Sounds counter productive to me however. Why would you want oily dust to accumulate on the paper element? You will not be able to blow it off as easily.

Personally, I've never done it and I'm not about to start.

You don't see oiled pre-filters on automobile air filters and I know my pick up sees more dust in just one ride to camp than anything else I use. Thirty miles per trip on a dry dusty gravel road is more than my mowers or Valkyrie will see in a lifetime.

If the truck doesn't have or need a foam pre-filter, why the need for one on machines working in cleaner environments using similar paper element filters?

 

[deeter16317]

If done correctly, oil shouldn't pass from the foam filter to the paper filter though...

I think its more to extend the life of the paper element than to increase filtration. Most mowers used without a foam filter (even a dry one) end up with a completely grass/dirt packed paper filter. The foam filter allows easier cleaning of the paper filter.

 

[Hootbro]

I have a 20 year old wood chipper/shredder that has a 8HP B&S on it with a foam pre-filter over the paper filter.

In that time, I have serviced/oiled the pre-filter every year. Not once was the paper filter ever saturated with oil. Maybe every 5 years the pre-filter was changed for a new one, but that paper filter has lasted fine for 20+ years. It was only this year that I changed the paper filter because age and ambient moisture has started to takes it toll and the media was breaking down. $5 later for a new filter and I am ready for the next 20 years.

 

[boraticus]

I'm curious why we don't see oiled pre-filter in autos?

 

[deeter16317]

Probably not as much "big" dirt to pre-filter?? Plus, too costly to maintain (service costs, added oil, added filter, etc.)?

 

[Bror Jace]

If you don't want to buy special motorcycle oil, you can use any motor oil (SAE30 is often specified).

However, I use chain & bar oil as it is cheap and contains extra tack additive making it better at trapping dirt.

 

[boraticus]

Originally Posted By: Bror Jace
If you don't want to buy special motorcycle oil, you can use any motor oil (SAE30 is often specified).

However, I use chain & bar oil as it is cheap and contains extra tack additive making it better at trapping dirt.


I also use bar/chain oil on the foam filters on my KLR and Suzuki off road dirt bikes. Inexpensive and very effective.

 

[Mamala Bay]

I use no oil on prefoam filters. The foam filters does an excellent job protecting the paper air filters. Never had a problem with that setup.

Foam filters are checked every 25 hours of usage. Clean if necessary with compressed air and if needed in soapy water. Paper air filters checked and clean with air compressor if necessary. Paper air filter changed yearly, foam filter twice a year.

Also when using oiled pre foam filters, when cleaning in soapy water they tend to alter in shape after cleaning a lot worse than with no oil. They don't last long I never found it necessary to use any oil on pre foam filters.

 

[deeter16317]

Originally Posted By: Bror Jace

However, I use chain & bar oil as it is cheap and contains extra tack additive making it better at trapping dirt.



Hmmmph, and its something I have on hand! Although I probably have a lifetime supply of actual foam filter oil...bought it a long time ago for practically nothing off eBay, before eBay got greedy.

Its not that I think they should or shouldn't be oiled, I run with and without the pre-filters on my equipment...really makes no difference because I change the air filter out once a year. I believe, like a lot have already eluded to, the pre-filter doesn't filter anything extra the paper element wouldn't normally catch...as I said, I think its just to keep the large debris out of the filter so that it has a longer useful life.

I just found it funny that I have been running equipment that had these foam filter wraps for years, and this is the first time I read where it was called out to actually oil them.

 

[boraticus]

"I just found it funny that I have been running equipment that had these foam filter wraps for years, and this is the first time I read where it was called out to actually oil them."

Same here. Since the original foam pre-filters were not treated with oil, nothing would lead me to believe that they are supposed to be. With a paper filter, one doesn't usually need to refer to the manual for maintenance.

Personally, I have no intention of oiling the pre-filters on my machines. As long as they catch the bugs and grass that's fine with me. I'll let the paper element catch the fine stuff.

I'd be more concerned about paper element fitting correctly and possible deformation.

 

[lexus114]

Originally Posted By: motor_oil_madman
Your supposed to squeeze the oil out of it. Put a small amount of oil on. Like a 3 teaspoons and then squeeze it up into a ball with your hands to spread it around. Then you can take a paper towel and squeeze the filter with the paper towel to get the excess oil off that way it is just damp with oil.



I used the K&N spray oil.It wasnt even enough to squeeze the oil out. :O,

 

[ProStreetCamaro]

I own 3 commercial ZTR mowers, 3 echo trimmer's and 3 backpack blowers. I use 20W-50 and put a little in my hand. Then roll up the pre filter and place it in the oil. I squeeze it and flip it over a few times to make sure it is soaked well. Then I squeeze hard to get the excess oil out and reinstall the pre filter. Been doing this for years with out any issues. Actually by doing this the paper filters still look nearly new at the end of a season.

 

[Mamala Bay]

Originally Posted By: ProStreetCamaro
I own 3 commercial ZTR mowers, 3 echo trimmer's and 3 backpack blowers. I use 20W-50 and put a little in my hand. Then roll up the pre filter and place it in the oil. I squeeze it and flip it over a few times to make sure it is soaked well. Then I squeeze hard to get the excess oil out and reinstall the pre filter. Been doing this for years with out any issues. Actually by doing this the paper filters still look nearly new at the end of a season.


The key is the pre foam protects the paper air filter and it helps a lot. Unwise not to use it given if one can be installed.

I just look at it differently, the foam filter can be air cleaned with compressed air and maintain it's original size and shape. With an oiled foam very difficult or impossible to clean with an air compressor.

Either way a pre foam filter makes a huge difference in protecting the paper air filter to do it's job.