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24 Dodge Brothers tours a park


austinsailor

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Spent yesterday touring Arches National Park in eastern Utah. Really neat day. Caused a lot of picture taking - and a lot of thumbs up. Held up traffic at times, but if there were any 2 finger salutes, I missed them!

 

But - and a big but. After about 4 years of occasionally driving this thing in many places and temperatures, I found a big shortcoming. 

 

It has the old vacuum tank for fuel delivery. If you are not familiar with them, they were a for runner of the fuel pump. They allowed the gas tank to be located low or in the rear instead of just gravity feed from a tank in the cowel. They do this by using vacuum to suck gas from the tank into a small canister on the firewall. It then gravity feeds to the carburetor. A float and valve tells it when to suck gas. Mine has worked fine for years.

 

Then, I go to this park with long, steep hills. Steep hills means full throttle for long periods of time. Overheating was not an issue, even though it was nearly 100. No vacuum at full throttle, though, was a big issue. No vacuum, no suckie has. Vacuum tank runs out, a couple early warning backfires from lean mixture, you're done! Stop, fill the vacuum tank from a gas can, repeat. Solution? Stay in low gear at about 5 mph so vacuum can develop.

 

i think I may install an electric fuel pump with a momentary contact switch to solve this.

 

Any thoughts are welcome.

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Trailered to Tomahawk, Wi for a week at the Antique outboard meet.

 

Then to Bozeman, Mt for a couple days around there. 

 

Then to Bonneville for a week of driving around there, around the pits, to the starting line (about 6 miles one way) and errands. 

 

Then to the Arches park. 

 

Now on the way to Missouri after visiting Garden of the Gods in Colorado Springs.

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Suggest you check to find out what the vacuum reading is when running and the vacuum fuel pump is running to see what it needs to operate.

Also what is the fuel pressure that the vacuum creates to the canister to make sure what the float and needle can handle.

 

Either a 6 volt fuel pump (with pressure regulator but not a cheapie) or a electric vacuum pump that only runs as required to assist (adjustable vacuum on switch)  , one problem is I have No idea if anyone makes a 6 volt version plus they are not cheap even for the common 12 volt ones!

 

Love the car especially when it gets driven!    ?

 

DJ

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I run a electric pump on my 23 Dodge brothers for over 20 years have only had a few times where it flooded the carburetor . Filled up the lower section of the carb and would not allow the sliding section to rise. Only thing i would suggest is to put a pressure regulator in as these old girls don't like much over  about 1 1/2 pound .

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Without disrupting to much to the mechanics of probably a mostly stock car, maybe try an aux. vacuum tank. But, if it's 12 volt, a backup booster pump would keep you with fuel, when you do pull long climbs again. You could have done Pikes Peak. Hopefully above idle speed.

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all you really need is a check valve in the line from the manifold to the vacuum tank.  Then, when climbing a hill you only need to "blip" the throttle to restore full vacuum in the tank.

This also helps when trying to start up when the tank has gone dry.

 

Not all cars using vacuum tanks had this feature, but Hudson did.   Greatly improved my 28 Chrysler  ( which originally used vacuum created by the oil pump )

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  As an add on, I have three of the vintage aux. pumps, two work only on 12 volt. The third one came off  a1952 B model with a Desoto 250. I'm hoping it's 6 volt, it's apart now, for a clean up. Looking at the pumps available now, it seems to be a matter of what best fits.But,then I found an adjustable Superior vacuum switch ,that you can adjust the  pressure between 6-22 inches. It's $40 bucks, but a nice add on to certain applications and a constant supply, within vintage specs. I have a Stewart model Y  vacuum fuel feed system tank hanging on the wall.One of those things that caught my eye years ago, when I was wrenching at a wrecking yard. 

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Assure there are no leaks in the vacuum source, lines and fittings.  Even as light leak can have a big negative impact.  An inline gauge would also serve as a leak down tester.  Fuel pressure is a non issue as its gravity.  An auxiliary vacuum chamber with check valve from a pick and pull would go a good ways to overcome periods of wide open throttle operation.

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I am wondering if momentarily taking the foot off the accelerator every 30 seconds or a minute would be enough to refill the vacuum tank. . . Works for me on my vacuum wipers when climbing a long hill, especially if it has been a while since I put Rainx on the windshield. That is maybe the work around would be a change in driving technique rather than a change in equipment.

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12 minutes ago, TodFitch said:

I am wondering if momentarily taking the foot off the accelerator every 30 seconds or a minute would be enough to refill the vacuum tank. . . Works for me on my vacuum wipers when climbing a long hill, especially if it has been a while since I put Rainx on the windshield. That is maybe the work around would be a change in driving technique rather than a change in equipment.

 

Tried this,  but unless you had a valve like mentioned in a previous post I think there would at best be just a few drops sucked in before the vacuum was again gone. I learned after a few times to recognise the start of starvation, could pull the richening valve  (similar to the choke) and let off the throttle and avoid a stop to reprime and get out the crank, but by then I'd be coasted to a stop and it was low gear again anyway.

 

Even driving as flat out as you feel safe on flat ground, no problem. But steeper grades it just didn't hack it, unless you stayed about half throttle, and that required 1st gear. Very slow and not very traffic friendly. Fortunately, I seldom drive where there are long steep grades. Running around Bonneville at 40 mph or so did fine. You just had to keep a tight hold on the wheel and stay alert!

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I wasn't confident in the vacuum canister fuel system when I restored my 1927 Chrysler and because went the 6 volt electric fuel pump and regulator route and found that I couldn't reduce the pressure enough to not over run the carburetor float needle. I ended up going back to the original vacuum canister and just spent a lot of time making sure everything was sealed properly and was surprised how well it worked. The car doesn't get a lot of driving and there are no 5 mile hill climbs around here but seems to work well for regular driving

Edited by 40plyrod
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