MB GPW Dry Air Filter Conversion Done
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MB GPW Dry Air Filter Conversion Done
Just a little after action report following my conversion of the MB's oil bath air filter to a dry element. I used this procedure and parts, with the Wix filter listed:
http://1945mb.com/c-80-G503_WWII_Jeep_O ... ilter.aspx" onclick="window.open(this.href);return false;
I'll tell ya, though, it wasn't as easy as one would think when looking at the short article linked above. The foam rubber "doughnuts" from McMaster Carr were both far larger in diameter than the OD of my original later MB air filter housing. They look almost nothing like the rings in the photos above, being far flatter and larger. I suspect that MC shipped me larger seals than ordered, but I'm not certain of this. Anyway, I could barely cram one seal into the oil pan. The other was simply far too large and would not fit into the filter cannister without creasing and bunching up unacceptably. I ended up X-Acto trimming a pie slice out of it, reducing the original diameter by somewhere between 1/6 to 1/8. I rubber cemented the trimmed ends together and the fit was better.
After buttoning everything back up, the old MB started right up, as it always does. It could just be my imagination, but the old girl seems just a little bit more responsive after this mod. At any given speed, the pedal doesn't seem to be as near to the floorboard as it did. Acceleraton seems marginally better. Idle is the same, with the same occasional *chuf*.
Time will tell if this was a worthwhile mod, I suppose!
http://1945mb.com/c-80-G503_WWII_Jeep_O ... ilter.aspx" onclick="window.open(this.href);return false;
I'll tell ya, though, it wasn't as easy as one would think when looking at the short article linked above. The foam rubber "doughnuts" from McMaster Carr were both far larger in diameter than the OD of my original later MB air filter housing. They look almost nothing like the rings in the photos above, being far flatter and larger. I suspect that MC shipped me larger seals than ordered, but I'm not certain of this. Anyway, I could barely cram one seal into the oil pan. The other was simply far too large and would not fit into the filter cannister without creasing and bunching up unacceptably. I ended up X-Acto trimming a pie slice out of it, reducing the original diameter by somewhere between 1/6 to 1/8. I rubber cemented the trimmed ends together and the fit was better.
After buttoning everything back up, the old MB started right up, as it always does. It could just be my imagination, but the old girl seems just a little bit more responsive after this mod. At any given speed, the pedal doesn't seem to be as near to the floorboard as it did. Acceleraton seems marginally better. Idle is the same, with the same occasional *chuf*.
Time will tell if this was a worthwhile mod, I suppose!
Last edited by tsmgguy on Mon Mar 12, 2012 6:25 am, edited 3 times in total.
Willys MB 236426, Hood 20336549, DOD 5-20-43
Piper L-4A "Grasshopper", Sn. 10371, USAAF 43-29080, DOD 5-28-43
Piper L-4A "Grasshopper", Sn. 10371, USAAF 43-29080, DOD 5-28-43
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Re: MB GPW Dry Air Filter Conversion Done
I ran into the exact same problem and had to take an exacto knife and trim those donuts. What I think the issue is in retrospect is the oil pan on the bottom was too shallow. I recently purchased an NOS and it is deeper than the one I had on it.
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Re: MB GPW Dry Air Filter Conversion Done
Something must have different for you. Mine went exactly as described in the article, took maybe 2 minutes at worst.
Dan
Dan
Dan Schultz
Retired USA SFC
GP 9275
GPW 14944 M38 MC70324
M38A1 MD20035
K-38 Lineman Trailer
Retired USA SFC
GP 9275
GPW 14944 M38 MC70324
M38A1 MD20035
K-38 Lineman Trailer
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Re: MB GPW Dry Air Filter Conversion Done
Thanks for the post sir, I was considering it myself and it is nice to hear that you see slight improvements in response or acceleration, immagination or not. I will have to try this conversion soon!
1943 Ford GPW, "Chattanooga ChooChoo"
325GIR, 82ndAB Living History
325GIR, 82ndAB Living History
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Re: MB GPW Dry Air Filter Conversion Done
I was struck by how clean the oil in the air filter pan appeared before I disposed of it. This was always the case, even though I live in the dusty desert Southwest. I was tempted to just pour the oil into the engine sump, but didn't as there's probably contamination that can't be easily seen. That old wet air filter worked! Also, it never leaked, even though there's no gasket.
Willys MB 236426, Hood 20336549, DOD 5-20-43
Piper L-4A "Grasshopper", Sn. 10371, USAAF 43-29080, DOD 5-28-43
Piper L-4A "Grasshopper", Sn. 10371, USAAF 43-29080, DOD 5-28-43
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Re: MB GPW Dry Air Filter Conversion Done
Being new to the hobby of jeep restoration five years ago, I had never heard of that type of oil bath air filter when I was putting an original 4 cyl. back in the jeep (my jeep came with a 6 cyl flathead and a pancake air filter). My dad (in his 50's) of course knew the type and told me all about it, It was really cool to put it back together how it was supposed to be, and I've never had a leak or any trouble with the oil bath but I still feel if I can get that dry filter and possibly improve at all in how it runs and accelerates I'm all over it!
1943 Ford GPW, "Chattanooga ChooChoo"
325GIR, 82ndAB Living History
325GIR, 82ndAB Living History
- Nikko
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Re: MB GPW Dry Air Filter Conversion Done
Hi Folks
http://www.richardmilitaryparts.com.au/FGPW.html" onclick="window.open(this.href);return false;
look att the picture it is a urethane/plastic spacer 2 stk.and 1large O-ring
,I have one kit inn my air cleaner 5.min innstall
the engine gets better air flow/breathing and a bit more throttle/accelration response is also a bit better
no more messy oil change for me
Cheers From The North
Nikko
http://www.richardmilitaryparts.com.au/FGPW.html" onclick="window.open(this.href);return false;
look att the picture it is a urethane/plastic spacer 2 stk.and 1large O-ring
,I have one kit inn my air cleaner 5.min innstall
the engine gets better air flow/breathing and a bit more throttle/accelration response is also a bit better
no more messy oil change for me
Cheers From The North
Nikko
1943 GPW 135099
1949 Spen 1/4 t trailer S/N 158
and a lot of nuts and bolts
1949 Spen 1/4 t trailer S/N 158
and a lot of nuts and bolts
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Re: MB GPW Dry Air Filter Conversion Done
I did the same conversion with the McMaster Carr rings and things fit perfectly in my original filter. No trimming was required.
CDR USN (RET)
Patrol Squadron 46 "Grey Knights"
Naval Flight Officer
Gulf War Veteran
45 GPW 271750
frame/engine match no data plates (DoD est. July 5 '45)
Patrol Squadron 46 "Grey Knights"
Naval Flight Officer
Gulf War Veteran
45 GPW 271750
frame/engine match no data plates (DoD est. July 5 '45)
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Re: MB GPW Dry Air Filter Conversion Done
Interesting! Beside being too large, the rings MC sent me had a pair of holes in each flange. These don't show up in the conversion photos linked above. I've contacted MC about this, and frankly, would like for the correct rings to be furnished, as ordered.Tim52 wrote:I did the same conversion with the McMaster Carr rings and things fit perfectly in my original filter. No trimming was required.
Willys MB 236426, Hood 20336549, DOD 5-20-43
Piper L-4A "Grasshopper", Sn. 10371, USAAF 43-29080, DOD 5-28-43
Piper L-4A "Grasshopper", Sn. 10371, USAAF 43-29080, DOD 5-28-43
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Re: MB GPW Dry Air Filter Conversion Done
Howard, did you ever get an answer from McMaster-Carr? I just received what looks to be the same gaskets that you got.tsmgguy wrote:Interesting! Beside being too large, the rings MC sent me had a pair of holes in each flange. These don't show up in the conversion photos linked above. I've contacted MC about this, and frankly, would like for the correct rings to be furnished, as ordered.Tim52 wrote:I did the same conversion with the McMaster Carr rings and things fit perfectly in my original filter. No trimming was required.
Regards,
Bill
1945 Ford GPW 268739 from the Dallas, TX plant.
- tamnalan
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Re: MB GPW Dry Air Filter Conversion Done
You all are using the McMaster Carr 2793K81 rubber rings?
They dropped right in for me too. No trimming at all. I'm also using the Napa 2036 filter. The rings looked just like the ones shown in the photo. I did this mod about 3 years ago. Perhaps McMaster Carr changed the specs on that number since then.
They dropped right in for me too. No trimming at all. I'm also using the Napa 2036 filter. The rings looked just like the ones shown in the photo. I did this mod about 3 years ago. Perhaps McMaster Carr changed the specs on that number since then.
Alan W. Johnson
_______________
MB, 201453, "Lt Bob"
MB, 1942, not stock
M-100, Sep 1951
MB-TD, Mar 2012
Ford 91C, 1939
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MB, 201453, "Lt Bob"
MB, 1942, not stock
M-100, Sep 1951
MB-TD, Mar 2012
Ford 91C, 1939
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Re: MB GPW Dry Air Filter Conversion Done
Yup. Just checked the packing slip and it says 2793K81 with a description of Toilet Bowl-to-Outlet Sealing Ring for 3" & 4" Waste Pipe, 3/4" Thick Sponge Rubber. Diameter appears to be 6 3/4 inches.tamnalan wrote:You all are using the McMaster Carr 2793K81 rubber rings?
They dropped right in for me too. No trimming at all. I'm also using the Napa 2036 filter. The rings looked just like the ones shown in the photo. I did this mod about 3 years ago. Perhaps McMaster Carr changed the specs on that number since then.
Bill
1945 Ford GPW 268739 from the Dallas, TX plant.
- WILLYS45
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Re: MB GPW Dry Air Filter Conversion Done
I am skeptical of chopping up the rubber seal rings to hodge podge this thing back together.
Last edited by WILLYS45 on Wed Feb 15, 2017 6:54 pm, edited 1 time in total.
MVPA Member #34754
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1945 Willys MB
Body/Frame #440438
Engine # MB487286
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1945 Willys MB
Body/Frame #440438
Engine # MB487286
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Re: MB GPW Dry Air Filter Conversion Done
I know what it is for sure....there are two different bottom pans available. One is shallower than the other. I know this, because I had to chop mine down, then sourced a better NOS pan and it is deeper so now I have to source the rings again and will not have to chop them.
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Re: MB GPW Dry Air Filter Conversion Done
The bottom fits fine enough, almost perfectly actually, it is the top part of the housing. The housing has an inner liner that is about 5 & 1/2 inches wide and the ring is about 7 inches without cutting it. If the inner lining was not in the can, I think I could make it work, but the liner looks like it is not removable in anyway.
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1945 Willys MB
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Engine # MB487286
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1945 Willys MB
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Engine # MB487286
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