How to cure vapor lock
- Thread starter verdirick
- Start date
quickchange
Well-known member
Rick . Hi . Good to see you at Reno. We ran 86mph at the salt in stock A cpe . Flathead. You may gets lots of comments on this one , I have tried along with others clipping two wooden clothes pegs on the line, If that does not work at least you can hang the washing out. Make sure you have orginal fuel line & no extra filters. Winter is coming so you will be ok. Derek from spring sunny day in NZ
Mike V. Florida
Well-known member
lindy williams
Senior Member
A 1/4" bakelite spacer placed between the manifold and the carb on mine improved the situation. I got the material from McMaster-Carr (mcmaster.com). It acts an insulator to keep the carb cooler so the fuel doesn't flash into vapor when entering the carb.
Also, the addition of MMO, or 2 cycle oil will slightly raise the boiling point of the fuel and help the situation.
Also, the addition of MMO, or 2 cycle oil will slightly raise the boiling point of the fuel and help the situation.
steve s
Well-known member
There have been numerous long threads on this in recent years. Use Search function for key words "vapor lock". Here's one that will get you started:
http://www.fordbarn.com/forum/showthread.php?t=111122&highlight=vapor+lock&showall=1
You will find every cure under the sun, plus a host of vapor luck deniers and semantic quibblers.
Steve
http://www.fordbarn.com/forum/showthread.php?t=111122&highlight=vapor+lock&showall=1
You will find every cure under the sun, plus a host of vapor luck deniers and semantic quibblers.
Steve
Tom Wesenberg
Well-known member
I only use the good gas, no corn crap gas. This solved my vapor lock.
John LaVoy
Well-known member
On our last Summer Tour we had about 25 Model A's traveling home from Michigan. The combination of equipment varied from close to stock to highly modified up to and including overhead set ups. Every one had vapor locking problems coming over the Continental Divide in Colorado except one car that was using ATF added to his fuel. It is pretty close to the Marvel Mystery oil and is less expensive. The ethanol added to the fuel seems to boil quicker that straight gas so that has increased the problem. Going to higher octane use to avoid the added ethanol but they now put 10-15% in all grades. So I guess my recommendation would be the ATF/Marvel Mystery Oil to solve your problem.
QGolden
Well-known member
Have any of you ever tried to the addition of Kerosine to an A that was prone to the fuel boiling problem? I can see where the addiotion of MMO would help by raising the boiling point, however MMO is not volatile as Kerosine (or Diesel) is.
it is worth noting when discussing this issue that Gasoline as we know it today is a distillate of several compounds. Some of those compounds blend at the Molecular level with the fuel and some are simply additives that will evaporate out, or settle out. In the case of fuel boiling in the Carb or Fuel lines, it is worth noting that depending on the season, and the State we live in, our fuels are different with different compounds and additives. Here in NH we have Winter Blends and Summer blends, each is different from a Volatility standpoint, volatility is a measure of the gasoline’s tendency to vaporize under a given set of conditions. So the car that is prone to fuel boiling in AZ, may not occur in NH, even if the operating condition and temperature are identical. Fuel in NH is simply not the same blend as fuel in AZ.
The low compression engines of this era run on Kerosine, many were run on it during the war because it was not rationed.
So I am wondering if any one who has the problem, has tried adding a gallon of K1 or Diesel to the tank?
it is worth noting when discussing this issue that Gasoline as we know it today is a distillate of several compounds. Some of those compounds blend at the Molecular level with the fuel and some are simply additives that will evaporate out, or settle out. In the case of fuel boiling in the Carb or Fuel lines, it is worth noting that depending on the season, and the State we live in, our fuels are different with different compounds and additives. Here in NH we have Winter Blends and Summer blends, each is different from a Volatility standpoint, volatility is a measure of the gasoline’s tendency to vaporize under a given set of conditions. So the car that is prone to fuel boiling in AZ, may not occur in NH, even if the operating condition and temperature are identical. Fuel in NH is simply not the same blend as fuel in AZ.
The low compression engines of this era run on Kerosine, many were run on it during the war because it was not rationed.
So I am wondering if any one who has the problem, has tried adding a gallon of K1 or Diesel to the tank?
steve s
Well-known member
I didn't try a gallon, but I did try a quart or two of diesel per tank. All it did was make the exhaust smellier. Others have reported more success.
Steve
QGolden
Well-known member
Thx for the reply. A qt. In a 12 gallon tank is one 48th or about 2%. I should think one could easily go up 20% win a low compression A with no other modifications. Leaning a bit with the GAV might be in order? I have dumped up 25% old Kerosene (just to get rid of it) in my Flathead 8N. Could not tell it was in there.
Patrick L.
Well-known member
I've used ATF in the fuel for low use engines, enough to let them smoke a bit. I always thought it kept the carbon soft and they store fine. As far as vapor lock is concerned, I agree with Mike in keeping a good pitch on the lines as well as making sure the battery ground connections are clean and tight. But, I've never experienced vapor lock in a Model A yet, I have in other engines though.