Venting the Distributor

[Riverrat]

Trying to figure this out. Do I:

1. Get a set of special bent tubes for carb horn (original design)
2. Use electric air pump (would appreciate advice on specs and where to tie into truck’s wiring and where to procure pump and air filter).
3. Don't vent at all

BTW, this truck is usually running very short distances at under 25 mph. Never driven over 45. Rarely on long (20 miles) distances.

Thanks!!

Chuck

[cuz]

#1 is the simple solution. Takes me every bit of 30 minutes and $5.

#2 too much work and money.

#3 With the high price of 24 volt coils item #1 sure sounds like a good idea.

Chuck, If you're close enough drive the truck over here and I'll do the whole shebang for $25.

[Riverrat]

Thanks for the offer, Cuz! You're only about 1000 miles down the road -- you got time just after dinner tonite? )

[ZGjethro]

I asked the same question of this board a couple of times. I built a straight air intake which uses a Kand N filter and I do not want to have to tap a bunch of holes in it. The best other option is using the vac pump part of the fuel pump to suck air through. Cuz has info on this.

I bought a 12 volt aquarium bubbler to vent the distrubutor, but I do not think I will use it. It might be $50 poorly spent. I did not want to add any more switches or relays. I have a master negative switch, the ignition switch, and my 12v fuel pump switch.. Three is more than enough.

I now think I will run one vent line to the dist from my intake, and just put a filter on the other side. I do not need river fording ability and I want a minimum of lines running over the engine to my nice new air intake.

[MSeriesRebuild]

I asked the same question of this board a couple of times. I built a straight air intake which uses a Kand N filter and I do not want to have to tap a bunch of holes in it. The best other option is using the vac pump part of the fuel pump to suck air through. Cuz has info on this.

I bought a 12 volt aquarium bubbler to vent the distrubutor, but I do not think I will use it. It might be $50 poorly spent. I did not want to add any more switches or relays. I have a master negative switch, the ignition switch, and my 12v fuel pump switch.. Three is more than enough.

I now think I will run one vent line to the dist from my intake, and just put a filter on the other side. I do not need river fording ability and I want a minimum of lines running over the engine to my nice new air intake.

If I'm understanding what you are saying correctly, I'm not sure you will have enough forced air flow to make it work. Fording capability isn't the real issue. Enough ventilation to offer cooling for the coil is the issue.

[cuz]

Charles is correct. It also is needed to remove the ionized air from the housing. Learned that new word a week or so ago right here. I use to just call that nasty air in there "Fumes".

The method I suggested when you asked before is still the easiest solution if you have the dual fuel/vacuum pump installed. Which you would need if you still have the vacuum wipers. It is based on the Willys jeep system. The intake sucks on the vacuum pump, the vacuum pump sucks on the wipers. You insert a "T" fitting in the line to the wipers. The line you add from there to the distributor needs about a 0.040 restricter in it. You can buy the Willys one or just get a nipple and solder it shut and drill a 0.040 hole in the solder. Run that one copper tube to the distributor (either side) and then on the other side screw in a spicer axle vent fitting with cap.

If you have the basic fuel only pump then just do this from the hole that was originally used in the intake manifold.

[Riverrat]

Is there a possibility that standard venting will not be effective at the low speeds I usually drive?

[MSeriesRebuild]

Is there a possibility that standard venting will not be effective at the low speeds I usually drive?

If you have a proper forced air thing going on, it will be good at any speed.

[Joe]

Is there a possibility that standard venting will not be effective at the low speeds I usually drive?

If you're using the intake manifold for a vacuum source it will be even MORE effective at low speeds! Carburated engines have a HIGHER vacuum at lower throttle openings. It's when you open up the throttle that you lose vacuum. That's why vacuum wipers work poorly at modern high road speeds but yet worked fine for the low road speeds in the era when they were designed and built. It's also why people install vacuum gauges and strive for the highest vacuum readings when trying to conserve fuel. (A smaller throttle opening means less air AND less fuel!)

[MSeriesRebuild]

The stock M37 distributor venting system has nothing to do with vacuum, it does not work like the system on jeeps. Both lines are attached to the carb elbow between the air cleaner and the carb inlet. The special fittings that the lines attach to at the elbow are position specific thus setting up the forced flow. It's all created by the air flowing in the elbow toward the carb inlet. If you are doing as customized system, you will just need to be sure of the flow as you chose to set it up.

[Riverrat]

...and all who cast light (+ventilation) on the subject...

[cuz]

When a thread like this gets long some folks miss many key parts of the discussion. To set the train back on the tracks here is the direction the two problem posters wanted to go:

First poster:

Riverrat » Tue Jul 06, 2010 9:41 am
Trying to figure this out. Do I:

1. Get a set of special bent tubes for carb horn (original design)
2. Use electric air pump (would appreciate advice on specs and where to tie into truck’s wiring and where to procure pump and air filter).
3. Don't vent at all

BTW, this truck is usually running very short distances at under 25 mph. Never driven over 45. Rarely on long (20 miles) distances.

Thanks!!

Chuck

My suggestion was to bend up a pair of new tubes and hook up the original vent system.

2nd Poster:

ZGjethro » said: I asked the same question of this board a couple of times. I built a straight air intake which uses a Kand N filter and I do not want to have to tap a bunch of holes in it. The best other option is using the vac pump part of the fuel pump to suck air through. Cuz has info on this.

My suggestion was to use the M38 system if he didn't want any lines connected to his modified induction system.

All three of us are aware of each type system and how they work.

[snowdad]

Does anyone possibly have any pictures of these lines and their routing?

[cuz]

I posted a few of the guy's engine photos at this thread:

viewtopic.php?f=3&t=3106

Not perfect but will give you the lay of the land.

[themoose74]

If you have the basic fuel only pump then just do this from the hole that was originally used in the intake manifold.

Cuz, if I am interpreting this correctly, is it possible to run the incoming vent line into the distributor from the port on the intake manifold? If so, where does the outgoing distributor vent line connect to send the "nasty, ionized air?"

I ask because I have a civilian carburetor perched on top of my manifolds and no vent lines. And I want to drive the truck, but not at the expense of frying the coil...or enduring the self inflicted stress of thinking I could burn up the coil!

Bo