Oil bath filter

I was wondering if anyone has used one of those old tractor oil bath filters with or without oil?

Eddy Ramos modified a vehicle oil bath filter for use on the charcoal gasifier for his truck. Check out A guide for driving a vehicle on chargas. You may find some information about it there.

Oil bath filters are not the most effective kind of filter. They work well within a specific range of flow but their efficiency drops outside this envelope. Paper works great at all ranges so that why one replaced the other inn its simplest explanation.

They do work well on a machine like a tractor that’s running under a pretty steady regular load in field, but they let a lot more dirt by compared to paper on a car for example. They do have the advantage of being easy to clean and in very dusty environments that’s a huge advantage that as long as you have oil around to put in them you are not without a filter.

About 50% of my fleet uses a oil bath the rest use paper of foam ( on machines with steady loads and speeds like generators the oil bath are just fine ) But if it moves changes speed or might tip over its paper or foam.


Hi Wallace. My first attemp was to use paper filter, but it colapsed very quickly when gets clogged with ash, and here in Argentina, paper filter are quite expensive. So I use an oil bath filter PLUS a microfiber towel both are low cost maintence because in the oil bath filter I use used motor oil and hand wash the towel.
Eddy Ramos.


The thought has been going through my head for oil or paper filters, but why not a aftermarket free flowing steel liner filter such as [email protected], or spectre. Here in the states they are fairly cheap, serviceable and easy to clean. I don’t know if it would work but if let’s say a weekly cleaning is all that’s needed? Could be an optional air filter

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most of the oil bath tractor kind are kind of a 3 part filter system
inside you have steel mush oil and they kind of vortex
they are made for dust hence why they use them on tractors
my kind looks like this
the oil portion sits in a removable “cup”
from my understanding ait travels in the top into the oil though the mesh to the oval portion then kind of spins

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perhaps this could be useful on other wood devices too many tractors used these in various sizes
this is one from a john deere twin so 2 of them might function well in a car type wood device


I use oil bath air filters. I like how they entrain tar, soot, and dust. People give filters to me for free. I use used vegetable oil, or used mineral oil for the bath. If I have steamy gas I use water to dehumidify the gas.
One note…if you use used vegetable oil with a tar maker, save that oil and coat the bottom of fence posts, or the bottom of barn siding with it.


The K&N filters seem too course for me. At least for a final filter. But your mileage will vary, so to speak. I use cheap water filters for final. Maybe 30 micron, I forget. Looks like paper but isn’t. Course filter I use cheap towel.


In extreme dust they are not going to clog but the oil will thicken into a paste that’s not going to filter anything. You need to be sure you clean them before the oil is too thick.

I think Toyota still has an oil bath as an option on the 75 series they sell in desert countries because its more effective to change the oil frequently than have a clogged paper filter fail

They let a lot of large particles pass. By the time its 50% clogged its finally performing as well as a paper filter.

Same goes for paper, you should only change a filter when your filter gauge tells you ( according the manufacturers recommendation ). By the time a filter starts to look dirty its probably 25% clogged but at this point the filtering efficiency has improved and its letting through fewer small particles than when it was brand new without making much difference in its actual ability to flow air.


Thank’s Wallace for your advise!
Eddy Ramos

In the past I have seasoned new filters with char dust.

I never heard of anyone doing anything intentionally to improve the filtering efficiency before. Interesting idea

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Wasn’t my idea. I read it on a woodgas list or forum.