MB GPW Dry Air Filter Conversion Done

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Re: MB GPW Dry Air Filter Conversion Done

Post by slugger53 » Mon Apr 30, 2012 6:05 am

hi, really like the sound of this conversion, but we don't have a Mcmaster carr here in the Uk, anybody here in the UK done this conversion and managed to source these rubber rings ok? if so where from? I've tried a few plumbers merchants but nothing so large can be found, do we not have drain pipes this big here in the UK?
also on the subject of what to do with the old oil, somebody wanted to do something with it as it was so clean, when taking it out of the bottom of the air filter, why not put it in your oil can and use it to lube anything that moves, that way its not wasted and it feels like you got it for free!


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Re: MB GPW Dry Air Filter Conversion Done

Post by dpcd67 » Mon Apr 30, 2012 1:32 pm

Yep, if you order that McMaster part number now, you will get two HUGE rings, over 7 inches in diameter; II took a pair of scissors and cut off a lot to make them fit. In the UK, aren't your toilet drains about 4 inches in diameter? I think any rubber or maybe even foam would work as well.
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Re: MB GPW Dry Air Filter Conversion Done

Post by slugger53 » Tue May 01, 2012 2:58 pm

has anybody done this conversion here in the uk? i can't seem to find any of the foam rings big enough, do we have smaller waste pipes? or is the plumbing really that different? even the filter is hard to get as most filter suppliers say this filter is obsolete here in europe, anybody got any ideas? i really like the idea of this conversion and an desperate to do it to my MB but can't find the parts, very frustrating.... all help and suggestions gratefully received

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Re: MB GPW Dry Air Filter Conversion Done

Post by slugger53 » Wed May 02, 2012 8:42 am

just read the other section on dry air filters, and near the end a few guys in the uk who have done this conversion, so sorry to be stupid, the answers were already there for me! cheers guys, i'll still post my results when I've sorted it as i want to do this conversion for myself and at least four or five friends who have jeeps also :D

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Re: MB GPW Dry Air Filter Conversion Done

Post by signsup » Tue Aug 07, 2012 4:38 am

I am in this process and have the filter from NAPA, but am fortunate to live a mile or so frm a MC distribution warehouse and will be able to actually pick up my rings rather than have them delivered. I will take my filter housing with me and make sure they fit and see if they have a reason for any difference in styles or dimensions.
These rings are being sold as toilet bowl gaskets, so having two bolt holes in them would not surprise me. But the dimensions should be consistent.

I believe very filter has the inner liner and that is the most important part of the oil bath system as the air enters in trough the back vents and goes through and around the inner liner before going through the oil bath and then coming up throough the inside of the inner liner where the outlet tube is connected. Any removal or trimming of the inner liner will negate any "tornado" effect of the entire air filtration set up. don't mess with it.
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Re: MB GPW Dry Air Filter Conversion Done

Post by signsup » Wed Aug 08, 2012 4:48 pm

OK, now I'm confused. I picked up my two foam rubber rings from MC today and they aren't even close to fitting. They are at least 3/4" too large in circumfrance. I have both a CJ oil bath filter that should be the same as the early GPW and a M38 oil cleaner. Both are exactly the same size and these rings are going to need to be cut down big time.

But what confusies me about the conversion is the height of this filter with these two rings on each end. As I view out the air flow in my mind, the air enter through the rear vents and hits the inner lining and then comes down to where the oil would sit and then goies up the inner chamber and out through the outlet to the carb. So this paper filter and rings need to go past the outlet tube to the top of the inner chamber to have the air flow through the center of the rings and paper filter out the outlet tube. But on both filters, the outlet tube sticks into the inner chamber and I'm not seeing how this filter and both rings get crammed up past the outlet tube. At least one ring must go all the way to the top of the inner chamber and then the paper filter and then the lower ring sits where it can.

The website that was hosting the original instructions is having problems and won't let my computer view it. How do the rings go on? Is the top ring smoother side up and the inner flange drops down into the filter center and the opposite for the bottom ring?

I'm just not seeing it in my mind.
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Re: MB GPW Dry Air Filter Conversion Done

Post by signsup » Thu Aug 09, 2012 5:46 am

I'm going to answer my own question here. I was able to get on the site where the original images are shown. It now looks like one ring goes in the oil bath bottom lid and really just hold the filter in place, has nothing to do with air flow. The air comes in from the rear vents along the double wall between the outer and inner liner, get to the bottom of the lid and instead of running over the surface of oil is now passed through the dry filter down at the bottom of the chanber. The air is passed through the filter at the bottom and goes up through the center of the filter and the center of the upper ring and comes out at the top of the inner chamber just below the outlet tube, and out the tube to the carb.

So the entire unit of filter and two rings has to be shorter than the distance from the bottom of the lower cap/lid to the bottom of the outlet tube. I'll go play with mine again. I know that the rings are way to large in diameter for a start, but I'll start trimming them down to the right circumference.

I also noticed that the part number of the filter and the actual filter used in the images are two different filters. NAPA 2036 is refrenced but a FRAM CA3445 is shown. I presume the same dimensions for both, but I'll look into that as well.

I'll report back. Interesting about the MC rings being different sizes for the same part number. I may shoot them an email as well to see if different suppliers to them supply different specs on the outer dimension. I did notice that in their catalogue it gives this part number for either 3" or 4" pipe on the inner dimension, so maybe they have two different rings with the same part number.

TO THE LABORATORY!!!
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Re: MB GPW Dry Air Filter Conversion Done

Post by signsup » Thu Aug 09, 2012 6:43 am

IGOT IT!!!

At least for me, this is what worked. I may go back and fine tune it a little.
A. The rubber ring goes around the filter with the flange side down towards the bottom of the cap. The filter does not sit on this ring, but is inserted into it. That solves the length problem. No trimming necessary.
B. Insert the ring and filter together as a unit into the lower cap. The foam rubber comporesses easily and will fill the entire bottom of the cup.
C. The upper ring will have to be tirimmed to match the inner diameter of the inner lining. In my case, about 1/2" all the way around.
D. I inserted the top ring into the inner lining of the air cleaner housing. It should stop at a formed lip just short of the outlet tube.
E. Push the lower cap/filter assembly into the upper housing and hold down and clamp your clamp fittings. Mine was really tight and feels like a slight gap between the cap the the housing when clamped shut. I know the foam ring is sealing it, but I don't know if it shows.

I think that if I tweek the cutting of the top ring so that the filter can actually go inside the ring instead of laying against it, it will not be so tight a fit and eliminate my gap. But when we starting trimming the ring, it made a big difference when we put the filter into the center hold. It pushed everything out. But it trims easily with a pair of scissors, so if I can put the filter into the hole in the upper ring and trim it to get a tight seal against the wall and upper lip of the housing, that will take some pressure off the clamps. But then it al has to just slide in and I'm not visuallizing that process happening too easily.

Fnal post. I promise.
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Re: MB GPW Dry Air Filter Conversion Done

Post by signsup » Thu Aug 09, 2012 6:50 am

I lied.

My way won't work. The reason the clamps are so tight is because the inner lining is hitting the rubber ring in the bottom of the cap. Therefore, no air will be able to get in from the double wal into the inner chamber. So both rings will have to be trimmed to fit in the inner lining. That is the key.

So I will trim both rings to fit inside the inner liner, but only the bottom one will go around the filter to hold it up from the bottom cap and in place. The upper ring will be on top of the filter so that it can slide in by itself and then the lower ring and filter can slide in.

Back to the laboratory.

This is embaressing to show al my mistakes in public. But, hopefully, it will save you from making the same mistakes.
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Re: MB GPW Dry Air Filter Conversion Done

Post by signsup » Thu Aug 09, 2012 1:08 pm

Boy, that was fun.

Here is final, final, final, final post on this subject, then if it doesn't work, I'm leaving the GD oil in it!

The top foam ring gets trimmed to match the diameter of the inner lining.
Place it in the inner housing up to the lip that is just underneath the outlet tube.
Place the filter inside the housing so that it is centered.
It MUST hang down lower than the inner lining for the air to pass through from the outer chamber through the paper filter at the bottom and then out the outlet tube.
Place your bottom ring on the bottom of the paper filter and center it.
Clamp on your bottom cup.
Some bottom cups are different and you may need to trip your bottom ring as well.

Clamps may be a little tight as they are now pushing up the entire filter unit to make a airtight seal, not just holding oil.

I'm happy with it, but not a slip in deal like the article indicates. I had to trim both rings on my canister. But $12 for two rings and $7 for the filter so under $20 for the conversion.

And the satisfaction that I figured this out all by myself after only 8 hours!

And, of course, I had to find the "F" marked rings and filters for my GPW! (just kidding)
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Re: MB GPW Dry Air Filter Conversion Done

Post by jonny427 » Wed Jan 14, 2015 2:34 pm

Robert thanks for all the input and public documentation of your troubles. Hopefully I can avoid making the same mistake as I attempt the conversion myself later today!
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Re: MB GPW Dry Air Filter Conversion Done

Post by Chuck Lutz » Sun Jan 18, 2015 4:51 pm

If you live in a dusty, desert environment or will be off-roading in the dirt...the dry filter is what you want. Otherwise, the oil bath has worked fine for a long, long time with very little problems....unless of course you are in an environment as described above.

When I change the crankcase oil I change the Air Cleaner oil bath at the same time. I haven't found much more than an occasional tiny dead bug or some dust floating on the surface of the oil itself.

No matter which system you use...remember to check the cup to see if water has intruded and begun to rust holes in the cup!
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Re: MB GPW Dry Air Filter Conversion Done

Post by rcskier » Mon Jan 26, 2015 5:43 pm

About to do mine tomorrow . Ordered from plumbing supply.com.rings seem to be just right!
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Re: MB GPW Dry Air Filter Conversion Done

Post by thovis » Sun Apr 05, 2015 8:41 am

Note: that article was updated a couple months ago, and confirmed, the McMaster gaskets size (smaller) were changed over 2 years ago. In addition it was confirmed that the plumbingsupply.com has the correct size.

This was updated in the article with the correct size needed. Hope it clarifies

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Re: MB GPW Dry Air Filter Conversion Done

Post by Marty, SoCal » Wed Apr 29, 2015 4:25 pm

To anyone who has done the toilet seal and air filter mod a long time ago, I have a couple questions!

How has the toilet seal held up over time?

Any flaking or deterioration of the foam from the fuel fumes or age?
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