Oiling Filters

[WHX?? 48,815]

Couple of filters for a Z turn. I know most books say to oil the outer foam and squeeze excess. Often times drips in the filter housing attracting more dirt and making a mess. 

Thinking the theory is the oil attracts small dirt particles like the old skool oil baths but shouldn't the paper filter do that too? Oiling the foam makes the inner filter last longer? 

The cheap price of these filters I'm inclined to not oil and just replace more often.  Many don't come with the foam anyway. 

Thoughts & comments? 

[Shynon 7,459]

Oil them!!!! Enough said 

[SylvanLakeWH 25,547]

 

Light coating on all such filters... 

 

 

[lynnmor 7,305]

I use the foam and lightly oil it.  The foam will catch a lot of dirt saving the rather expensive paper element.  Usually only the very fine particles get thru the foam, so when checking the paper element hold a light inside.  I have had some that looked almost new that turned on the dash light meaning they were in need of replacement.  If you have two foam pre-filters, you can rotate leaving one to dry after washing.

[Pullstart 62,840]

Still no better filter than an oil bath… if you ask me!  Oh yeah that requires maintenance!

[Achto 27,569]

I bought a can of K&N filter oil about 7yrs ago. I give my new foam filters a light spray with it, also use it again if I wash the foam filter out. 

https://www.napaonline.com/en/p/BK_990516?cid=paidsearch_shopping_dcoe_google&campaign=GSC-Chemicals&campaign_id=6478876245&adgroup_id=115972171828&adtype=pla_with_promotion&gclid=CjwKCAjwo9unBhBTEiwAipC110cZP7CmvCxbDFq7UYgpRinRWXSjBolxxHAdbeFc_9lns0ESNS4vsBoCK68QAvD_BwE&gclsrc=aw.ds&

 

Yes it is expensive but I'm still using the same can that I bought 7yrs ago, figure I have another couple years left in the can yet.

Edited September 5, 2023 by Achto

[WHX?? 48,815]

Might just have a can of that yet if I can find it...

[JoeM 7,873]

Air filter is the most important filter on a an internal combustion engine. Dust it one time and the life span goes south quick. 

These engines ingests dirty air with enormous quantities. 

I look back at what was going on with the big earth moving machines. All the ones I seen were dry and changed out on cycle times.

One big deal was personal doing a sloppy job changing and introduced dirt into the system.

I think that pre-filter is just a gimmick. A false sense of getting longer life. But it can't hurt with oil on it or not. I would not use it as a substitute to changing the main element. 

And don't blow out that paper element with an air hose, change it!

 

[lynnmor 7,305]

1 hour ago, Joey Small Block said:

 

I think that pre-filter is just a gimmick. A false sense of getting longer life. But it can't hurt with oil on it or not. I would not use it as a substitute to changing the main element. 

And don't blow out that paper element with an air hose, change it!

 

My Onans collect considerable amounts of grass, leaf and other debris, that gimmick stops much of it from reaching the $15 paper filter. 

[JoeM 7,873]

41 minutes ago, lynnmor said:

that gimmick stops much of it from reaching the $15 paper filter.

yep

but just think how much dirt that you can't see passed through the foam into the paper.

that arrangement on the onan is questionable. the way the air enters the fan housing and is blown into the air filter. 

If you getting that much debris inside of the air filter housing, might want to think about changing the air inlet.  removing the inlet tube and installing a cover over the hole?? 

might save you a couple $$

[peter lena 8,619]

@Joey Small Block AGREE WITH YOU , on the air intake re routing , why not ?  looking at the issue, is the dust bowl , generated by the mower deck , other attachments , REPADITIVE PROBLEM , why not plan out a better set up ? don't have a twin  , but if I  did , would make a point of eliminating many of the chronic problems . just my own view of  regular  problems , pete

[WHX?? 48,815]

3 hours ago, lynnmor said:

 $15 paper filter. 

These were two for 10. I pay 15- 20 for two on my Kohlers. 

All my Onans cept the FEL just see sno duty but yes they are a tad more$$. I buy the Onans with the pre filter but only the FEL gets oiled. 

5 hours ago, Joey Small Block said:

look back at what was going on with the big earth moving machines. All the ones I seen were dry and changed out on cycle times.

And look at the dust they see. I would think heavy equipment would have dual elements like modern farm tractors. 

[Handy Don 12,216]

17 hours ago, Achto said:

I bought a can of K&N filter oil

I use this as well, and the aerosol delivery makes it easier, for sure. No more drip and squeeze. 

[RED-Z06 2,221]

The thought process and filter process has changed from the way it was done "in the old days". 

 

20+ years ago you would absolutely want to oil the pre-filter.

 

However modern engines are designed to be used dry, but theres a reason for it, and its actually very clever.  Old engines the filter was just under a cover and dirty air was pulled in, the pre-filter caught and held big items to prolong paper filter life, and the oiled filter would usually clog up quickly.

 

Modern engines, and some olders like Onan, use centrifugal forced air injection.  Dirty air is pulled into the flywheel cowling, with most heavy particles being thrown away by centrifugal force...and air is forced by ducting to the filter housing, where it blows across the filter then exits out somewhere else..taking loose particulates with it...the idea has become about cooler cleaner air blowing across the dry foam filter, while most particals simply blow through.  The dry sleeve acts as a first line of defense and holds big stuff and gives it a chance to blow off and out.

 

It's entirely common to pull a filter off an engine at 50hrs, wash a bit of dust off the pre-filter and the main filter is still clean.

 

Meanwhile my K301 i can mow 3 acres and my oiled filter is caked solid...and the main filter is visibly dirty.

 

[WHX?? 48,815]

  @RED-Z06

[JoeM 7,873]

12 hours ago, RED-Z06 said:

the idea has become about cooler cleaner air

good idea, bad application on a WH

that cool air thing might work on a enclosed engine compartment but it is all open for the ambient air anyway. 

 

Lynn has a good point about saving on the filters. 

I just think rerouting the air intake would be a better fix.

I had this one in a couple weeks ago, the filter was trashed, and the guy said he blows it out with air. Oh, and it is using more oil. I had it running in a place where you could see a blue haze in the exhaust stream. I think it is hurt. 

Wonder if we can flip over the air cleaner lid like the old days and let it breath from that direction??

[peter lena 8,619]

@WHX??   been using k/n  air filters for years , even have one on my horse , its a Harley filter , https://www.google.com/search?q=oiled+air+filters&rlz=1C1CHBF_enUS866US866&oq=oiled+air+filters&aqs=chrome..69i57j0i15i22i30j0i22i30l6j0i10i15i22i30j0i15i22i30.12512j0j4&sourceid=chrome&ie=UTF-8#ip=1  regularly look over things , have them in my cars , pete

[RED-Z06 2,221]

25 minutes ago, Joey Small Block said:

good idea, bad application on a WH

that cool air thing might work on a enclosed engine compartment but it is all open for the ambient air anyway. 

 

Lynn has a good point about saving on the filters. 

I just think rerouting the air intake would be a better fix.

I had this one in a couple weeks ago, the filter was trashed, and the guy said he blows it out with air. Oh, and it is using more oil. I had it running in a place where you could see a blue haze in the exhaust stream. I think it is hurt. 

Wonder if we can flip over the air cleaner lid like the old days and let it breath from that direction??

WH is actually a great application, cool ambient air is in great supply.  Deere for example with the same engine had to add sealing insulation at a bulkhead to keep hot engine compartment air out of the flywheel inlet, whichcdraws air from the dash area.  Onan lids don't seal to the bases so excess air flows out the seam at the lid

[lynnmor 7,305]

2 hours ago, peter lena said:

@WHX??   been using k/n  air filters for years , even have one on my horse , its a Harley filter , https://www.google.com/search?q=oiled+air+filters&rlz=1C1CHBF_enUS866US866&oq=oiled+air+filters&aqs=chrome..69i57j0i15i22i30j0i22i30l6j0i10i15i22i30j0i15i22i30.12512j0j4&sourceid=chrome&ie=UTF-8#ip=1  regularly look over things , have them in my cars , pete

 

I really thought, you of all people, would not use that trash.  This testing has been done a long time ago and shows how much dirt the oiled "filters" pass.

[RED-Z06 2,221]

1 minute ago, lynnmor said:

 

I really thought, you of all people, would not use that trash.  This testing has been done a long time ago and shows how much dirt the oiled "filters" pass.

Right?  I put a k&n on my old 85 vette and within 6 months had idle problems and a light.  Cleaned maf sensor and idle valve...6 months later it was back.  This went on for 3 years.  I switched back to the paper filter and voila...no more problems.  The oiled cotton was letting past fine dirt that stuck to the mafs sensor and made the iac valve sticky.  Never again...ill take filtration over a few cfm of flow

[peter lena 8,619]

@lynnmor  actually have never had any related  car issues with them , if I  had ,I would not have recommended them . the Harley model filter is an exact fit in my 312 , along with a few other , you can't do that changes , instant starts and no  related carb issues . my 2017 Volvo also has one with no issues , emissions test  , good to go . regularly experiment with any  regular service areas . carb clean them , reoil good to go . that horse has a number of  tests going on , car bole , electric fuel pump, 5 / 16  clear fuel line , vertical fuel check valve , spring assist on fuel / choke cabling . wiring reroute , transaxle  climbing gear oil , its all working , a gain in every area , reliability , consistent starts , zero noise , easier shifting . 3 springs under my seat , plug is clean , runs like it should , added Zink in the engine  too , clean and zero smoke . make problems go away , thanks for the shout , pete  

[lynnmor 7,305]

Destroying an engine with more dust than necessary is a long process.  There is no need for dusting an engine unless one needs just a bit more power to win a race at all costs.

[RED-Z06 2,221]

52 minutes ago, lynnmor said:

Destroying an engine with more dust than necessary is a long process.  There is no need for dusting an engine unless one needs just a bit more power to win a race at all costs.

When we raced karts in a spec engine class we ran a foam filter with an oiled sleeve with a knit sock...dirt still got through and it showed after about 700 laps, but if we ran a paper filter..we'd have been last, once one person committed to trashing their engine we all had to.

[bds1984 1,429]

3 hours ago, RED-Z06 said:

Right?  I put a k&n on my old 85 vette and within 6 months had idle problems and a light.  Cleaned maf sensor and idle valve...6 months later it was back.  This went on for 3 years.  I switched back to the paper filter and voila...no more problems.  The oiled cotton was letting past fine dirt that stuck to the mafs sensor and made the iac valve sticky.  Never again...ill take filtration over a few cfm of flow

I bought an F150 years ago that the previous owner had ran a K&N air filter on it.  The MAFS and IAC were trashed and what a nice fix a few weeks into owning it.  I tell this story to my students so they don't waste money on it as they always tell me the "mods" they are doing to their cars as the get their license.  Fast forward a few years to my buying a nearly new Crown Victoria LX Sport that had one on it.  Luckily no drivability issues or CELs, but I performed a used oil analysis before and after changing out the K&N filter, and as one would expect, silicone (dirt) numbers dropped like a anchor in the deep six.  
I will give K&N credit, they are excellent at separating money from people and the hype of their air filters.  Their oil filters on the other hand, are rebadged Mobil 1 filters with a 1" hex nut tacked on the end for a much easier removal, and worth the few extra dollars.  

[RED-Z06 2,221]

23 minutes ago, bds1984 said:

I bought an F150 years ago that the previous owner had ran a K&N air filter on it.  The MAFS and IAC were trashed and what a nice fix a few weeks into owning it.  I tell this story to my students so they don't waste money on it as they always tell me the "mods" they are doing to their cars as the get their license.  Fast forward a few years to my buying a nearly new Crown Victoria LX Sport that had one on it.  Luckily no drivability issues or CELs, but I performed a used oil analysis before and after changing out the K&N filter, and as one would expect, silicone (dirt) numbers dropped like a anchor in the deep six.  
I will give K&N credit, they are excellent at separating money from people and the hype of their air filters.  Their oil filters on the other hand, are rebadged Mobil 1 filters with a 1" hex nut tacked on the end for a much easier removal, and worth the few extra dollars.  

About 15 years ago K&N partnered with a few OEMs and started offering drop in replacement filters for small engines,  the prices were obscene and you had to do the cleaning and oiling process regularly...but after a year they vanished from catalogs and shelves, they killed alot of engines

 

Edit: looks like k&n still sells them but the manufacturers and aftermarket suppliers won't touch them

Edited September 7, 2023 by RED-Z06