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Toyvo
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Joined: Sep 06, 2014
Posts: 30
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 Posted: Sat Sep 06, 2014 8:41 pm Post subject: PCV VALVE or PCV ORIFICE ? |
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| Hi all this is my first post here. I have taken on a repair project for a neighbor on his 1951 M38. The complaint was poor idle and hesitation. As a long time (40 year ) mechanic my first thought was tight valves and possible carburetor adjustments. Also it has a long hard start issue. He left the vehicle with me and I began with a valve adjustment, the truck sat over night and the next morning I began pulling the valve cover. I soon realized it might be easier to remove the intake/exhaust assy. for simpler inspection and adjustment. When removing the intake I found a broken ear on the 4-3 runner. Bingo I said vacuum leak. It was leaking and a few of the valves were tight. As I reinstall a new intake manifold and assembled the related parts I attempted to blow thru the PCV system. Hummm!? the piping seams to be clogged. Further testing showed a closed deep water fording valve. I used easy off oven cleaner to clean the valve and opened it with some vice grips. Ahhhh!! the system is now open. But it is open all the time suck or blow??? I re-inspected the PCV valve and discovered their was nothing in the valve, just a small orifice hole. I assumed it was bad so I ordered a new one. the new valve is the same way. Is this normal or do you order the guts of the valve separately. It was unusual to me to see a PCV system on a pre 1969 vehicle. I have other issues on this repair and will be back with other questions. |
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wesk
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Joined: Apr 04, 2005
Posts: 16256
Location: Wisconsin
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Toyvo
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Joined: Sep 06, 2014
Posts: 30
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| Posted: Sat Sep 06, 2014 9:32 pm Post subject: |
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| Wes nothing was in the valve housing. but it did have what looked like a seat with no spring or ball/bullet. Can these be ordered separately? |
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wesk
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Toyvo
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Joined: Sep 06, 2014
Posts: 30
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| Posted: Sun Sep 07, 2014 5:26 am Post subject: |
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| I got a W0-A6895 (valve assy.) The assy. suffix tells me it's the complete part. Nothing is inside of the housing but what looks like a seat and orifice hole. |
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Toyvo
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Joined: Sep 06, 2014
Posts: 30
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| Posted: Sun Sep 07, 2014 5:39 am Post subject: |
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I read the post about the 2 types of PCV valves. I will also try to used this valve and only hope the carb is set up for a planed vacuum leak. Maybe that is why the idle mixture screw isn't making any difference when screwed all the way in when I had the deep water fording valve closed and vented the valve cover to atmosphere. Just go's to show it makes no difference how long you have worked on cars, there is always something to learn.  I'll post later on the outcome. |
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wesk
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Location: Wisconsin
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Toyvo
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Joined: Sep 06, 2014
Posts: 30
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| Posted: Sat Sep 13, 2014 6:22 am Post subject: |
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OOOOK !!!
The fuel pump is in with the spacer, new fuel and vacuum lines are installed (as close as I could to original), the tank is clean, no longer leaking, and a new fuel pick up plate with filter are installed. Along with the new in tank filter I gained a vent line. For now I have it routed to the driver side of the tank and it stops there. I don't have the information as to where it go's but think it should go to the air breather. (we don't have the original air breather YET!) Also I installed the pcv orifice and opened the fording valve.
I installed fuel and spun over the engine. No fuel, so I spun it again, still no fuel. I removed the suction line hooked a portable fuel tank and gave the fuel pump a prime. Spinning it over with the battery charger connected and coil wire removed, I loosened the line at the carb. I have drips of fuel but not squirts of fuel. I must have damaged the fuel pump when installed without the spacer. NEW PUMP COMMING! 
"Those fording valves were only meant to be closed for very short periods during fording"
Yes Wesk I am aware of this. And I am sure that is why this engine has oil all over it. I am hoping it didn't ruin the seals. We will know after I get her running and over to the car wash for an engine detail. The valve is now open and I did run the engine using gravity feed from my portable fuel tank. It runs ok but cant run it long enough to make adjustments. |
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wesk
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Posts: 16256
Location: Wisconsin
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| Posted: Sat Sep 13, 2014 9:22 am Post subject: |
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You would of needed to bash that pump terribly hard to break it during insertion into the block. My guess is you missed the cam for the lever and lever is riding on the wrong side of the cam and there's probably nothing wrong with the fuel pump. You can confirm this yourself by taking the pump off and operating it by hand with the hose from it's inlet to your gas tank. If you have a civvy pump (single or dual action) you do not use the spacer.
Only a very small percentage of early M38A1's ran a vent line from the fuel tank vent port to the aircleaner (1952 thru Oct 53). The rest had a vent valve installed in the port.
_________________
Wes K
45 MB, 51 M38, 54 M37, 66 M101A1, 60 CJ5, 76 DJ5D, 47Bantam T3-C & 5? M100
Mjeeps photo album: http://www.willysmjeeps.com/v2/modules.php?set_albumName=Wes-Knettle&op=modload&name=gallery&file=index&include=view_album.php |
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Toyvo
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Joined: Sep 06, 2014
Posts: 30
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| Posted: Sun Sep 14, 2014 6:50 am Post subject: |
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Thanks for the pic. but my tank is set up different. the hold down strap go's lt. and rt. and the vent and pick up plate is located near where the letter (C) is located on the picture.
I have a fuel pump with a vacuum pump on the bottom of it and was lead to believe this is a military vehicle used by the Civil Def. on US soil only. So far the info in the Military operation and organizational maintenance manual have been spot on when compared to this unit. Also the id plates on the dash show this to be a build date of 9/51. |
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rgmutchler
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Joined: Sep 28, 2008
Posts: 345
Location: Caldwell, Texas
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wesk
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Location: Wisconsin
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Toyvo
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Joined: Sep 06, 2014
Posts: 30
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| Posted: Mon Sep 15, 2014 6:36 am Post subject: |
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| Quote: | Wes,
I think Toyvo said in his first post that he had an M38 not an A1
Ralph |
What is the A1 designation? Maybe I do ? Guy's this is a whole new ball game for me. My thing is air cooled VW, old Chevys, and all other old imports. |
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skyjeep50
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Joined: Feb 20, 2007
Posts: 606
Location: Illinois
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| Posted: Mon Sep 15, 2014 7:58 am Post subject: |
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If you go to the "Downloads" section of this website you can explore and read and download tech, parts and maintenance manuals for M-series military jeeps including the M38 and M38A1. Scroll through the pics, diagrams and parts lists and you will get a feeling for the differences and similarities between models. In the "Photo Gallery" you will find an extensive collection of pics of member's projects plus technical pics with measurements and descriptions of all sorts particularly in WesK's gallery. Tons of info!
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1951 M38 |
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wesk
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Joined: Apr 04, 2005
Posts: 16256
Location: Wisconsin
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| Posted: Mon Sep 15, 2014 8:00 am Post subject: |
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The Willys model designations were easier to follow than the military's.
M = Military
A = 1st design MA (Military used the same designation)
B = 2nd design MB (Military used the same designation)
C = 3rd design MC (M38, M38CDN)
D = 4th design MD (M38A1, M38A1C, M38A1CDN1, M38A1CDN2, M38A1CDN3)
D-A = 5th design MD-A (M170 ambulance)
_________________
Wes K
45 MB, 51 M38, 54 M37, 66 M101A1, 60 CJ5, 76 DJ5D, 47Bantam T3-C & 5? M100
Mjeeps photo album: http://www.willysmjeeps.com/v2/modules.php?set_albumName=Wes-Knettle&op=modload&name=gallery&file=index&include=view_album.php |
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