m38a1 air filter

zeke57 · Post by **zeke57** » Thu Jul 26, 2018 11:21 am

I disassembled my oil bath air cleaner and the retainer assembly was full of what looked to be steel wool mixed with nut shells so I assumed something had got in there and built a nest but then I got to wondering if that material is supposed to be in there.

mdainsd · Post by **mdainsd** » Thu Jul 26, 2018 12:21 pm

Not the nut shells, LOL. the filter is fibrous and relies on being oil soaked, but not clogged.

Oil bath air cleaners are junk, plain and simple. They cannot come close to the particulate size filtration that oil/gauze or dry paper can do.

Ive gutted every one of my military oil bath air cleaners and modified them to run a K&N style oil gauze filter. You can't tell looking at the air cleaner that it has been modified, but gone is the mess and hassle of cleaning the old one.

zeke57 · Post by **zeke57** » Thu Jul 26, 2018 12:28 pm

That is interesting could you explain to me how to modify it.

Eades · Post by **Eades** » Thu Jul 26, 2018 1:01 pm

I am interested as well.

mdainsd · Post by **mdainsd** » Thu Jul 26, 2018 1:05 pm

In a nut shell (sorry, couldn't resist!). I gutted the upper portion of that thing that contains the horse hair or whatever. It takes a little patients as there were some spot welds to remove and you don't want any evidence of the mischief going on inside.

Then I fabbed up a flat plate that fit up in the top piece. Opened a hole in that accepted a sheet metal tube sized to accept a K&N cone shaped filter onto it.

I went a bit overboard and made another round plate with the big hole in it. It has pem nuts (captive) pressed into it. It in turn is fastened up into the upper filter house with structural adhesive (steel reinforced). The you mount the K&N to the plate with the tube using a large hose clamp. Then screw that assembly to the plate up inside the A/C.

Hope that makes sense?

zeke57 · Post by **zeke57** » Thu Jul 26, 2018 2:38 pm

Do you have a part number for the K&N filter?

billybob · Post by **billybob** » Thu Jul 26, 2018 3:58 pm

Zeke 57, send me your E-mail address to robertlewis121@yahoo.com

Post by **wesk** » Thu Jul 26, 2018 11:43 pm

Here are about 50 photo sources of various ways to convert the Willys oil bath filter to a paper element.

https://www.google.com/search?q=Convert ... Al6BAgFEA0

4x4M38 · Post by **4x4M38** » Sun Jul 29, 2018 5:19 pm

The term junk to describe an oil bath filter is interesting.

Donaldson and others still manufacture the oil bath filter,
particularly for very dusty and dirty off road conditions.

Many on road big trucks still use them today.

Wes has a good description somewhere on the theory
of operation. Properly maintained and serviced as required
it performs as advertised.

Still, many have done what you have and replaced the guts with
a paper element.

mdainsd · Post by **mdainsd** » Sun Jul 29, 2018 10:23 pm

"Properly maintained and serviced as required."

To me this is precisely why they are not the best choice, the maintenace and servicing is a pain in the rear . That and add the mess, the weight and the waste you have to get rid of every (often) filter service.

Maybe there are still some suitable applications, but they are not common any more.

4x4M38 · Post by **4x4M38** » Mon Jul 30, 2018 12:24 pm

Curious.
Do you have a Cuno or Military Junior oil filter?

mdainsd · Post by **mdainsd** » Mon Jul 30, 2018 1:03 pm

Both. One jeep with each.

m38a1 air filter

m38a1 air filter

Air filter.