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VaporLock Ruminations...

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  • starliner62
    I feel your pain. I have one car that exhibits the same problem. The first thing I found was the heat riser staying closed. The fuel would boil out of the carb. I "adjusted" the heat riser to stay open and that helped. Next, I replaced all of the rubber hose that someone installed instead of the steel line with new steel line. It has improved, but like yours, a long traffic light will make it want to vapor lock.
    My son's 58 was doing the same thing and I replaced the fuel pump with a modified Mopar unit. He drives his daily with no issues.
    I'm thinking about an electric pump for the 55, but I have to find a 6 volt pump.
    Make sure you timing is where it should be. That will also cause more heat if not correct.

    Good luck.

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  • reichsrundfunk
    started a topic Fuel System: VaporLock Ruminations...

    VaporLock Ruminations...

    Hi Gang,

    I recall a few weeks backs seeing something on VaporLock on one of the forum lists but damned if I can find it again, so I apologize in advance for repeating a subject:

    My 63 Lark (with 253 V8 & 2Bbl carb) has begun exhibiting Vapor Lock issues now that the weather is warming. I exhibited it a bit last summer shortly after I bought the car but for some reason it seems worse this spring. On Thursday it was 81 degrees outside and during a drive of about 55 miles both interstate and county roads, the temp gauge was running between 190 and say, 205 and after each full stop, as I was accelerating the engine would exhibit the usual starving for fuel symptom of Vapor Lock. At one point it died completely and I pulled to the side of the road, popped the hood and let the engine cool down a bit. I also removed the fuel line from the filter and sucked up gas (yum) to get liquid fuel up into the lines again past the vapor. A couple times of that and she restarted just fine, but again after the engine temp went over that magic 190-200 point I had to be careful accelerating after a full stop to prevent it from dying out. I did stop to do some shopping for about 2 hrs and left the hood up. After that she drove home just fine the last 4 miles. It exhibited the same issue again yesterday just driving around town locally, showing some slight symptom of fuel starvation as the temp gauge hit about 205 degrees. So right now I don't feel comfortable driving it anywhere till I get this corrected.

    It seems that the fuel begins to vaporize and the pump has difficulty pumping gas when the temp gets up over 190-200 degrees. Below that she runs like a Swiss watch.

    Now I recall some years back experiencing the same issue with a 1951 Land Cruiser I had with the V8 engine. In that car the fuel pump was located on the top of the engine so it was especially susceptible to heat exposure. What I did to fix the issue was I installed an electric fuel pump ahead of the mechanical pump and ran the electric to a toggle switch I concealed under the dash. As I was driving if I felt the engine begin to starve for fuel I'd just flip the switch and within two seconds I was thrusting ahead good to go. I'd typically leave the electric on till I reached my destination or if the engine temp cooled down to where I would just switch the electric pump off. I'm thinking this is the way to go with my Lark. Running the electric pump pressurizes the fuel line as well as forcing liquid gasoline forward and preventing the fuel from vaporizing at that lower 190-200 temp range. I know its due to the damned Ethanol in the fuel..........

    So, here are my two thoughts on this and I'd like to see what you experts think is the best way to proceed: should I stick to my original plan and install an electric pump ahead of the mechanical pump (which by the way was replaced last September so its fairly new) and switch it on only when needed to pump gas forward to the mechanical pump, or should I just bypass the mechanical pump entirely and use the electric as the one and only fuel pump, with it wired thru the ignition? The mechanical pump is supplying gas at a rate of between 4 and 4.5 pounds to the filter and carb.

    Incidentally, since replacing the mechanical fuel pump I find that the fuel line (and visible in the fuel filter) is dry after sitting overnight, and I have to crank the engine for a few seconds to get fuel pumped up into the filter and carburetor. After it starts its good all day. My old Land Cruiser had the same condition. Now, with my electric pump arrangement I had with the Land Cruiser, I would switch on the electric for a couple seconds and that would pump up gas into the lines and fill the filter & carburetor bowl. Then the engine would start virtually instantly when I hit the starter, no cranking to bring up gas.

    Thanks guys,