Fuel Starvation

Thanks to all who have offered such great suggestions. Also appreciate it not degenerating into a "Vapor Lock Doesn't Exist" debate. I don't care what we call it, fuel stops flowing to the carb, and whatever you call it, it won't run that way!

To answer some questions posed: 1. There are no fuel filters installed other that those Henry designed and installed. 2. I rebuilt the main shutoff valve and installed a new strainer screen on top as provided in the rebuild kit. 3. I dismantled the Cast Iron sediment assembly mounted on the engine side of firewall, cleaned with Muriatic Acid, quenched in soda, and installed all new fittings. 4. Installed new Snyder's provided steel gas line direct to carb, with no auxillary filters inbetween. 5. I had the gas tank professionally cleaned but wasn't satisfied with the results, so cleaned it again with Muriatic Acid then lined it with a hard epoxy liner. I had previous experience with the liner, never a failure. 6. Installed a new gas cap, checked to see that it was vented.

Some things I may have done wrong: 1. As suggested, it does have winter gasoline. I had filled all my gas cans last fall when prices started to sky rocket, using STABIL in them, so that is what is in the car. I will drain the tank and fill with fresh summer fuel. In all my other antique fire truck, tractors, and 216 Chevys I run Automatic trans fluid, about 1 pint to 20 gallons of fuel as a valve lube. Began doing that after visiting BG Products main factory here in Wichita. Talking with the lab manager on a car tour, one of our guys asked him what he thought about MMO. He responded that it was an excellent product, did what it said it did, in fact, he said they couldn't find any real difference between MMO and Auto Trans fluid, except for 6X the cost. So, I have used it with good results in all my old vehicles. Hadn't put it in the Model A as yet, but will do that with the fresh gasoline. 2. I have no shielding for the carb between the carb and exhaust manifold/exhaust pipe. Will do that tomorrow. 3. I have no insulation on the steel gas line. I will dod that tomorrow as well.

Things I have decided as a result of the excellent suggestions from you all. 1. Will leave the heater manifold in place. 2. Will leave the splash pan in place for now. 3. As mentioned above, will insulate the gas line and fabficate an AL2 shield around carb. 4. Considering changing the cast strainer to the glass bowl type of sediment bowl. 5. It seems to make sense to me to provide an air intake passage from carb inlet to outside the engine compartment as one gentleman suggested, but will wait to see if the rest of the solutions resolve the problem. 6. I don't want to resort to buying real gasoline eventhough I strongly believe corn makes better breakfast cereal and cow feed than it does automobile fuel! And I say that with some authority. I used to manage the Design Engineering Department at Coleman (Maker of Coleman lanterns and camp stoves.) I learned first hand about the BTU content of alcohol relative to real gasoline, and also the horrible nasty affect the additives had on our vapor generators and all the other components. Lots of re-design required to burn the crap! Back to my reasoning for not trying to resolve it with real gasoline, on tours it probably won't be available, and I want to have a fix that works all the time, not just when I can find good gasoline.

WIll let you know how it turns out after another test run tomorrow afternoon with the fixes incorporated as noted above.

Thanks again for all the comments and ideas.

Ron
 
Ron,

The only reason I suggested placing the removable larger rubber hose over the aluminum foil gas line wrap was for aesthetics; i.e., not having a makeshift shiny homemade kitchen look in the engine compartment of a vintage vehicle.

Best of luck tomorrow, & thanks for your kind words mentioned for everyone.
 
OOPS, sorry for the double post, I didn't notice it had gone to two pages and when I didn't see my response, assumed I forgot to hit the "Submit Button."

Ron
 
I am having the same problem with my car which has a Zenith carburator . I just talked to a fellow that has experienced this problem and he said the Zenith carburator is cast iron and gets very hot and causes the gas to vaporize internally in the carburator when the out side temp. is hot . He changed to a Tilson caburator and had no more problems .
 
UPDATE -- Put an insulator tube on the steel gas line, and fabricated an AL2 heat shield above carb and in front of exhaust pipe/manifold connenction. Left the winter fuel in and took it out for an 89 degree drive. Carb was running 151 degrees, but now with the heat shield in place, only got up to 124 degrees, ran perfectly, never missed a beat. Filled up with summer gasoline and going for a 60 mile run this evening, showing off to relatives at a picnic. Thanks to all who provided some great ideas.

Ron
 
Duffy1 said:
I have a clear fuel filter and have witnessed the gas to start to boil and the engine starts running rough . I moved the gas line as far away from the exhaust manifold as I could and still remain inside the hood . Seems to have helped althiugh when I stop and let the engine sit for a hile and then get start it and take off it will die of fuel starvation after going about 100 yards . Some of my club members say it is air in the line . They suggested I pull out on the choke and see if that helps . Yet ET
Click to expand...


I took my car out today . Stopped at a coffe shop ,came out about thirty minutes later started the car pulled out in traffic and the engine started to die due to loss of fuel . I pulled out on the choke,it kept the engine running ,then I pushed in on the choke , and the engine stumbled along for a little while and then started running as if nothing ever happened .A fellow model a`er I know has a theroy that the Zenith Carburator ,since it is cast iron ,gets very hot and acts like a heat sink . So when you drive in the heat and then stop for a while the carburator actually cooks the gas setting in the gas bowel causing to much vapor which is fine to start the engine but will not keep it going down the road ,therefore the engine dies . His solution was to change to a tolliston carb or any other carb that is not cast iron .
 
Ron,

I knew if this did not work, only ice on your carburetor would work.

One more important thing to help prevent carburetor heat gain:

1. You have reflectively lowered the radiant heat for the carburetor by 27 degrees; but maybe not the heat gain by heat conducting through the steel intake manifold, to the carburetor.

2. The carburetor can get hot with heat by conduction throught the hot intake manifold.

3. The thin carburetor paper gaskets are OK in Alaska & Siberia; but If you do not have a few, get the thicker copper/asbestos gasket recommended by Ford & sold by vendors for about 10 times the price of paper gaskets -- you will save money on the first tow job.

4. It is most difficult to get heat to transfer through asbestos -- the inner copper crimp on this original gasket will prevent gasoline from "wicking" through the asbestos -- do not overtighten & make this gasket too thin.

Hope this helps.
 
Random thoughts:
1- Reports of large air bubbles coming up fuel line, passing through glass sediment bow & belching on up to tank, I wonder if gas boils in the cavity where the screen resides in the top of the carb & creates enough pressure to push air back up fuel line???
2-I've read that side pans prevent some of the fan's air from going out the bottom which helps more air to flow around HOT manifolds & carb & exits out through side hood louvers??
3-I've never had fuel starvation from heat, even in 110 to 112 degree and running around town. I run the in tank filter, cast sediment bowl, Zenith carb, 6 blade plastic fan, a Walker, 10 fin per inch radiator, and side pans.
4-Once, I installed 2 small boat bilge fans under the carbs on a Datsun 260Z to keep them from boiling the gas in the float chambers. Wonder if someone makes them in 6 volt?
5-Just a thought, cut a 2 inch hole in R/H side pan under carb, spot weld a 2 inch, 90 degree exhaust pipe elbow in the hole to scoop up air below the pan & blow it straight up under carb??? Bill W.

Ron,
Have you considered running a few days without the hood to see if it helps? Myself, I would try a stock manifold, maybe that would help? Bill W.
 
Ran about 60 miles last night with the ambient temp at 92 degrees F, never missed a beat. I'm not going to argue with the "Vapor Lock is a myth" experts because for them it can't happen, didn't happen, will never happen. I would simply mention that I didn't change the coil, I didn't change the condensor, I didn't do anything except fabricate and install an aluminum shield between the top of the carb and exhaust manifold, letting the back extend and bend down to shield it from the entire exhaust pipe until it exits the splash pan. And I installed an insulating sleeve over the steel gas line. The huge difference in the carburetor bowl temperature, reducing from 151F to 124F with all else the same says to me that there is a direct correlation. I would also note that several posts say the corn fuel boils between 100 F and up to 400F. I agree with that, however; have you ever noticed that when boiling eggs, steam begins to rise above the pan long before the water actually boils? this tells me that even though the fuel is not actually boiling, it is forming vapor. NO NO NO it isn't vapor, lets just say that it is air introduced from some unknown source that prevents the gasoline from flowing into the carburetor and leave it at that.

Once again, thanks to all the ideas and suggestions, you guys did allow me to find a workable solution in very short order.

Ron
 
Ron,

Since we are discussing a very deep subject such as vapor lock myth & boiling eggs, many of our rural generation are aware that fresh eggs that are boiled are far more difficult to peel than eggs which are about 2 weeks old.

People always fight peeling boiled eggs because the egg white stick to the shell, thus making a mess when preparing delicate stuffed eggs.

SOLUTION: Vapor lock myth is the secret: Next time in lieu of boiling eggs, place them in the top a covered double boiler with about 2" of water in the pot below -- boil the water, "not" the eggs -- allow the vapor lock myth to steam the eggs for 20 minutes -- remove from heat -- eggs are "hot", do not touch, but allow eggs to cool in air or faster cool water prior to peeling.

Vapor lock myth eggs are more than twice as easy to peel -- fresh eggs or without fresh eggs -- not everyone is aware of this. Just try it for an experiment!

If Model A manifolds can boil water, one could produce vapor lock myth eggs on the along highway.
 
Would be happy to share the photos, but haven't attached photos before and don't know how to do it. Can anyone give me the steps involved?
Thanks, Ron
 
Ron Kansas said:
OK, I know that 100 guys will jump in and say tha Vapor Lock is a complete myth, doesn't happen, 95% of vapror lock is actually ignition problems that show up when engine is hot.
Click to expand...

Read the "Vapor lock!" thread. Based on info I found, and contrary to my own beliefs, it can happen. I have read a lot of posts that also blame the addition of ethanol. In this case the ethanol lowers the volatility of the fuel i.e. higher boiling point. Higher the boiling point the less vapor to lock up the fuel system.
 
Ron-

For attaching photos...

At the bottom of the thread is the 'Quick Reply' box - below that is a button 'Go Advanced' - click that. Takes you to a different reply screen...

Scroll down that screen and you'll see a section that says 'Additional Options' - second area says 'Attach Files'.

Click on 'Manage Attachments' - a new window should pop up (if not, check to see if you have pop ups blocked in your browser settings).

In this new window there are a series of 'Choose File' buttons - each one allows you to attached a picture (or other accepted file formats). Click on the button and browse to where you have the pictures stored on your computer. Double click on the file name and it should show in the box next to the 'Choose File' button. Repeat if you have more than one picture (or other file - up to 7 per post). When you have all the pictures you want to include selected - click on the button that says 'Upload" that is next to the last 'Choose File' box. You should see a list of the files appear in the 'Attach Files' area.

You can then preview the post or submit the post and the pics should be attached.

Hope this helps...
 
OK guys, trying to uload a photo. This is the first "Quick and Dirty" version, it works great. I made it out of .025 AL2, and hand bent everything. Now that it works, I plan to get a piece of .035, and take it to factory where I retired, borrow their shears and hand break. I will fold the edges 180 and make nice straight bends so it will look a bit more professional.

Ron
 

Attachments

  • Model A heat shield 003.jpg
    Model A heat shield 003.jpg
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A couple of days ago, we went for a drive intending to cover about 70 kms (42 miles). It was very hot, about 32 *C. The initial 10 kms was downhill followed by a fairly level road. After travelling some 22kms, the engine hesitated a couple of times followed by loosing almost all power. We pulled off the road to investigate the problem. My initial thought was a fuel blockage so removed the carby, blew out the jets as best I could, checked fuel flow to the carby and replaced fuel line and carby.
The vehicle ran perfectly for the next 5 kms or so before it once again began to backfire and subsequently loose power. We were able to pull over and allow the engine to cool down somewhat. By now, we were on the hill climb returning home, the temp had dropped and the engine had cooled down. The final few kms home were without any drama.
My conclusion was fuel in the fuel bowl overheating causing the fuel to boil thus causing fuel starvation .
I will be investigating making up an aluminium heat shield as per previous posts.
 
Ron
It sounds to me like your fuel line is clogged however I could be wrong. ( First time) After you have checked timing, muffler restrictions, etc. Get some racing gas. You can find a dealer on line. If your car runs fine with the alcohol free racing gas your problem is probably vapor lock. The racing gas will work fine in your A even though you don't need the high Octane. I use it in my car before I put the car away for long periods of time because the alcohol in gas dissolves the tank sealer I used.
 
Try changing your condensor . Especially if. You did not have this problem before and it all of a sudden it appeared it seems that some of the condensor sold over the past few years do not totally blow the will allow them to run but not good they may run good cold until they start warming up its a easy try ? Let us know what you find
 
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