Sooty Exhaust

1952 - 1968, M38A1, M170, questions, discussions, regarding anything related to the M38a1 series.
lesk
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Re: Sooty Exhaust & more

Post by lesk » Mon Sep 04, 2017 8:06 pm

Thanks ScoutPilot....clear, straight forward point form answers....many thanks....yeah I am stumped on the oil loss as well.....PCV valve was also my thought.....do you have to replace it or can it be cleaned & any tips on how to?

lk


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Re: Sooty Exhaust

Post by Scoutpilot » Tue Sep 05, 2017 1:55 am

The shell should separate into halves. Inside will be a cone and a spring. Use a good carb cleaner and reassemble according to the info at this link;

http://oldjeepcarbs.freeforums.net/thre ... esign-l134

When completed, the unit should rattle a bit.
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Re: Sooty Exhaust

Post by lesk » Tue Sep 05, 2017 11:28 am

Thanks so much for the explanation and link...got it!

I will try to take out the PCV valve in the next day or two. However, other possibilities have come to my attention to check for unexplained oil loss....can I plug up the bell housing hole for a few drives and see what comes out after?

Also, the fording valve between the PCV valve and side cover bolt housing has been disconnected....the cable is still there but disconnected from the lever....what position should the lever be in? Right now, the fording lever is laying down parallel with the PCV valve....should the lever be at 90 degrees to the PCV valve?....not sure but can the position of the lever affect oil consumption?

Regards,

les

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Re: Sooty Exhaust

Post by Scoutpilot » Tue Sep 05, 2017 4:00 pm

The fording valves are supposed to be closed ONLY for deep water crossings. A closed valve will affect the operation of the motor in a negative way. With the lever parallel to the tube assume it is open until you actually verify it.
'70-'71 'A' Batt., 377th FA, 101AB
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'48 B1PW126
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Re: Sooty Exhaust

Post by lesk » Tue Sep 05, 2017 9:46 pm

Thanks ScoutPilot....I verified it a few hours ago....its in the open position...at the same time I took off the valve to get at the PCV valve which I thought I would clean...not so....I tried with two 12 inch wrenches, sockets & liquid wrench...I could not take off/open the PCV valve or even take it off its left brass elbow joint....I reefed on it hard with wrenches but I did not want to bend or crack a fuel line....any Ideas to try and crack open the PCV valve?

les

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Re: Sooty Exhaust

Post by Scoutpilot » Wed Sep 06, 2017 1:13 am

Sounds like a PO might have used a sealer on the joints. Chuck the nipple end tightly in a vise, with the nipple down, and try it. If that doesn’t work, let it soak for a couple of days in a 50/50 mix of acetone/transmission fluid then try again. The last resort is use a propane torch to heat it up and break the seal.
'70-'71 'A' Batt., 377th FA, 101AB
(Slicks and LOH's)(Col's LOH Pilot)
'71-72 CHARLIE TROOP,
16TH AIR CAV, 1ST AVN BDE (AEROSCOUTS)
LOW LEVEL HELL.
'46 CJ2A
'47 CJ2A
'48 CJ2A
'48 B1PW126
'69 CJ5

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Re: Sooty Exhaust

Post by lesk » Wed Sep 06, 2017 8:57 pm

Thanks ScoutPilot....I will try the soak method....if unproductive....I will try heat as a last resort.

lk

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Re: Sooty Exhaust

Post by Joe Gopan » Thu Sep 07, 2017 4:20 am

The purpose of the two fording valves is to seal off the crankcase ventilation which will pressurize the crankcase and prevent water from entering. Many M-38/M-38A1 Jeeps still have evidence of safety wire holding them in the open position. There was a bulletin or MWO back in the 50's to this effect ad many drivers neglected the position of the valves which caused the engines to pressurize. The fording valves were eliminated in factory mid-production M-38A1 Jeeps and were only installed on Jeeps in units needing the fording capability as part of their mission.
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Re: Sooty Exhaust

Post by lesk » Thu Sep 07, 2017 3:01 pm

Hi Ben....thanks for coming into the conversation.

So, I have finally got the PCV valve off of the brass elbow above the fuel pump...took it apart and it was almost like new...so I re-installed it and left the fording valve open.

So, the PCV valve is clean & open, I virtually do not have any exterior oil leaks when standing still and only 1-2 drops of oil from the rear main seal after a drive and that stops when cooled and I see no oil (never) coming out of the bell housing plug hole. I do not see any blue smoke on start-up (ever), I see no smoke of any kind while driving and the compression (on a down hill) is quite good, I have no restrictions in the air cleaner----not sure about the rubber hose to the carb but I assume if there was a restriction, the jeep would not run or idle as well as it does, the spark plugs (2243's) do not show any heavy carbon deposits (in fact the electrodes & insulators were a light-med tan color), the antifreeze is clean and bright green with no evidence of oil and finally, the oil filler neck or dip-stick does not show any malted milk sludge ......so why am I going through a quart of 15W-40 in about 400 miles....could the sooty exhaust have anything to do with the oil loss and where the heck is it coming/going?

Regards,

les


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