Distributor Cooling Lines Pics

1952 - 1968, M38A1, M170, questions, discussions, regarding anything related to the M38a1 series.
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w30bob
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Distributor Cooling Lines Pics

Post by w30bob » Mon Apr 10, 2017 6:01 am

Hi Guys,

Noticed this weekend the previous owner didn't have any cooling lines hooked up to the distributor. He didn't have a crossover pipe off the top of the carb either. Where can I find pics of how the lines to/from the distributor are routed and where they go? I looked in the ORD and it doesn't show the line routing. I'll pick up a crossover tube and get the current Solex carb off this thing as soon as I rebuild my YS, but I'd like to know how the distributor lines get routed so I can rig something up in the mean time before I cook the coil.

thanks,
bob


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Re: Distributor Cooling Lines Pics

Post by W. Winget » Mon Apr 10, 2017 5:18 pm

It would be a new system to me if there was a cooling line hooked to a distributor, I've never heard of such a need in 40 years of collecting.
Would you be talking of the 1/8" pipe and hoses that connect the distributor (and brake master) to the air cleaner, providing air when fording, thereby allowing the distributor to remain sealed 100% of it's life and the spark to continue and the brakes to get air above the fluid during action?
They are not pressurized and merely act in a static manner providing clean dry air into/out/pressure changes within the devices, not for cooling (that I have ever heard of) Wish I had a diagram to send you, but the only reference I could think of would be the -20 parts manual, or the -34 depot level parts manual potentially with a photo of the replacement parts. Proper term would be distributor fording vent tube (potentially)
Hope I'm correct and it helps clarify it for you. NO NEED for them if you never go under water by the way....but don't plug their holes up.
Do plug the hole in the side of the air cleaner though.
V/R W Winget
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Re: Distributor Cooling Lines Pics

Post by w30bob » Mon Apr 10, 2017 6:40 pm

Hi W,

Yes, that's the system I'm talking about. It is in fact for cooling the distributor. And it's needed because the distributor is waterproof. The coil is buried inside the distributor and generates heat (all coils do). If there was no airflow thru the distributor the coil would literally cook itself. I'm more familiar with the M37 system, as I'm new to the jeep thing, but it serves the same function on both vehicles. On the M37 airflow is generated by having one of the tubes to the distributor face forward inside the air cleaner to carb elbow. As the carb sucks air thru the elbow some of it goes into a special fitting inside the elbow connected to one of the lines to the distributor. The outlet tube from the distributor goes back to the elbow and connects to another special fitting that faces backward in the elbow.........creating an air ejector. This guarantees a positive flow of air thru the distributor.

On the M38A1 it seems they use the vacuum source from the fuel pump in the wiper circuit to pull air from the carb crossover tube thru the distributor. Both ways seem to work. If you still don't believe me think of it this way..........if you only wanted to vent the distributor (to keep it waterproof) you'd only need to use one line from the distributor that ended above the waterline somewhere. That's all that's needed to allow any pressure inside the distributor to equalize to outside pressure. But the distributor has two lines going to it, not one. You'll also notice exactly where on the distributor the two lines enter and exit.........on both sides of the housing where the coil sits, which makes the air flow thru the well the coil sits in. You don't need moving air to vent, but someone sure went thru a lot of trouble (and used a lot of parts) to make sure that air does flow around the coil and out. Also, a simple vent should be located in the cap somewhere, not in the coil well, as it's the ionizing of the air (the sparks jumping the gaps) that creates the ozone you might want to vent out of there. That's a very complicated system just to vent a dizzy. The M37 manuals talk specifically about it, so I'd be surprised if the M38A1 manuals don't mention the importance of thiscooling system.

regards,
bob

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Re: Distributor Cooling Lines Pics

Post by TGP » Mon Apr 10, 2017 6:53 pm

Exactly right Bob.
It needs to have air circulating regardless of fording or not.
I can tell you the metal supply line from the air intake tube
goes to the inside port of the Dist,
The other line goes from the outside port next to the ign, feed wire to the
Wiper supply "T" with a special fitting to control Vacuum.
I think that fitting is restricted at .040" diameter.
Winget is misinformed.
Your coil will not last long without air for cooling and removing vapors.
If his does last it's because he's not running any lines and just letting dirty air enter through open
Ports.
Tom
"47" Dodge WDX ww
"52" Dodge M37 ww
"54" Willys M38A1
"65" Kaiser M35A1 ww
"86" M1028A2

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Re: Distributor Cooling Lines Pics

Post by w30bob » Tue Apr 11, 2017 4:55 am

Hi Guys,

I did find answer to my question..........there's a good diagram of the system in the ORD, pg 70-71. I was looking at a different parts list that didn't show that diagram. It is a pretty complicated system compared to the M37, and since the previous owner replaced the mechanical fuel pump with an electric I need to buy that as well. So all in all getting this system back to functioning is going to be pretty expensive. Yikes! I need to buy a fuel pump, YS carb (which I have a core for), the crossover tube kit, the orifice and all the plumbing, and I might as well put back the vacuum wipers while I'm at it. Hopefully I can find some of this stuff at the upcoming east coast meets in a few weeks.

regards,
bob

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Re: Distributor Cooling Lines Pics

Post by Joe Gopan » Tue Apr 11, 2017 6:08 am

The vent lines are just that, cooing, if any, is incidental.
For all these nice to find (and many times now rare bits and pieces) it is best to choose a dealer who can supply you the majority of these needs. Not all make it a point to stock these special items and those who can help appreciate loyalty and will pull rabbits out of their hats.
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IF YOU REALLY WANT TO KNOW

Post by Joe Gopan » Tue Apr 11, 2017 10:31 am

IF YOU REALLY WANT TO KNOW:
And Col.Winget and Tom do understand the M-Series Ventilation system.

The Vent Lines from the air cleaner elbow to the oil filler pipe, distributor, fuel tank and brake master cylinder provide filtered air and protection from water for these units.
Simple, ain't it? :wink:
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Re: Distributor Cooling Lines Pics

Post by W. Winget » Tue Apr 11, 2017 1:42 pm

1st I checked RONs site for the below, no joy.
Here's one dealer for $120 (complete set)
https://www.armyjeepparts.com/p-3621-ki ... m38a1.aspx
(Image wouldn't pop up, pile of about 12 lines pre bent for the price but that may include fuel lines in their kit)
2nd dealer has each line (4) for $15 each line,
http://blah blah.com/m38m38a1fuel.htm

I just typed in "M38A1 vent lines"

I'm not worried about being wrong, I learn things if I am.... today I learned there are indeed two vent lines on the M151 series as well, early had a vacuum pump, later used the intake manifold to pull air. I will abstain from discussing the cooling effect, but it makes perfect sense to me, seeing the short life of many coils. (while surfing for these photos found a neat coil repair technique using a modern coil inside an old coil housing too, but it's off topic)

Below you can see lines from both jeeps, the M38A1 pulling air for the vacuum pump through the distributor, then to the windshield wipers (and brakes?) the M151 up to the A1 had a similar two vent system due to the vacuum pump needing air. The M151A2 did away with the pump but ran the suction pipe to the intake manifold, and the input to the ventura above the carb, MAYBE this line incidentally provides an air leak which many M151 owners are not easily locating, So I'm fully happy to learn.
V/R W Winget
Image
Image
Image
Image
Early M151 still had two Vents (9) as well, later models did away with vacuum pump and had the intake manifold pull air:
Image
Later M151A2 had the intake manifold suck air through the distributor at (12):
Image
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Re: Distributor Cooling Lines Pics

Post by w30bob » Thu Apr 13, 2017 10:13 am

Hi Guys,

I've got the complete set of "not so complete" lines on the way. The description says this set contains "most of" the lines for the ventilation/fording system, but when I asked the gal who answered the phone which lines it didn't include...........she had no clue. And she didn't now how to find out. So it's like the Obama-care bill........you have to buy it before you can see what's in it. :lol:

I suspect it doesn't come with the two copper lines to/from the distributor, as the pic of the set only showed a pile of steel lines. So I'll let you know what I get when they arrive. Now I just need to round up the brass fittings and the orifice. I found another discussion on here from a few years back talking exactly about this topic and it includes lots of good info. I believe the ORD also lists the line lengths for each tube.........so I should be up and ventilating/cooling shortly. Well......once I rebuild my YS and find a fuel pump. :mrgreen:

I do have a question about the pump, but I'll start a new thread later.

Have a good one,
bob

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Re: Distributor Cooling Lines Pics

Post by W. Winget » Thu Apr 13, 2017 5:43 pm

If any of the fittings from a MUTT can help, just let me know and I may have some I can pull for you.
V/R W Winget
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Re: Distributor Cooling Lines Pics

Post by 4X4M38 » Fri Apr 14, 2017 4:05 am

Bob,
All of the manuals are on the WillysMJeeps site free to download along with hundreds
of photos. All of your questions can be answered by visiting. There is a member that
was selling all of the vent lines for the A1, and rest assured he and others there
know exactly what's needed.

http://www.willysmjeeps.com/

Take care,
Brian

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Re: Distributor Cooling Lines Pics

Post by Joe Gopan » Fri Apr 14, 2017 5:34 am

And the reason for the copper at the distributor is that they are subject to flexing during the timing procedure., The 3/16" Inverted Flare Nuts are Steel.
2011 MVPA PIONEER AWARD - MVPA #1064
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Re: Distributor Cooling Lines Pics

Post by w30bob » Fri Apr 14, 2017 9:00 am

Hi Guys,

Thanks so much. Folks are visiting this weekend for Easter, but when they leave on Monday I'll get right on this one. My line kit should be here by then as well. Dad's outside right now drooling all over my jeep as I type. I got a feeling we're just going to have to go for a ride or two.......... :mrgreen:

You guys have a great Easter weekend!

bob


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