Re: Anybody got the end all cure for vapor locking?

Posted by DavidM On 2022/1/4 16:10:21

I missed the point that your vacuum tank does not work. Does your electric pump bypass it? If not it should however I would recommend you fix the vacuum tank. The electric pump should only be switched on to overcome vapor lock otherwise it can overcome the carburetor cut off and flood the carburetor. Much has been written about that.
Your experiences with opening the hood are exactly the same as mine. Also when I parked my cars in summer I always left the hood open otherwise the car would be hard or impossible to start unless they had hours to cool down.
Someone mentioned diesel instead of kerosene. I tried it once on a long trip in hot weather when the car was constantly vapor locking, I can't remember the % added but it was a lot. It made no difference good or bad.
On that trip I improvised a way of holding the hood sides up a couple of inches while driving. The increased airflow into the engine area significantly reduced the problem. Later in the day a cool change occurred and the vapor lock problem instantly stopped. I have driven one of my 1929's in light snow and it never ran better.
Another time I had to drive when it was just over 100 deg. I constantly had to stop to wet the carburetor and vacuum tank to cool them. That provided instant but very short relief.
I should add most of the time my 1929's were great cars to drive. I drove the 633 Roadster on many long-distance tours over twenty years. It did not have an electric fuel pump, only the vacuum tank. The other car was a 633 Sedan and I fitted it with an electric pump bypassing the vacuum tank. So when it vapor locked I switched on the pump giving almost instantaneous relief most of the time. On very hot days nothing much works. Stay home or stop and wait for the sun to go down!