| EWATERS | -- 03-16-2012 @ 4:06 PM |
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I have a 1950 Ford with a 6-cylinder engine. My restoration has progressed to enable me to actually drive the car occasionally. I find that, after driving and then shutting the engine off, it is difficult to start again. I have been informed that this is due to fuel foaming. It was suggested that I install insulation on the fuel-line between the fuel-pump and the carbeureter.(sp?) Can anyone provide some insight re this situation. Where might I obtain such insulation for installation? Any help will be greatly appreciated; thank you.
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| Stroker | -- 03-16-2012 @ 4:57 PM |
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E: There is no 32-53 Ford (6 or V8) that will benefit from pump to carburetor insulation if everything is as it should be. Fuel "foaming", often referred to as "vapor lock" is generally a symptom of other issues. A starting point in this discussion would be a fuel pressure check when the motor is hot. Please keep this thread alive by submitting your results, as that gives us a lot more to go on in isolating your problem.
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| kubes40 | -- 03-16-2012 @ 5:13 PM |
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Stroker, Once again, I am in your corner (share your opinion) 100%. If the carburetor, fuel pump, lines, coil, timing, etc. are functioning correctly there is no reason the car should not start well hot or cold.
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| ford38v8 | -- 03-16-2012 @ 5:27 PM |
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Mike & Dan, our friend in Florida (GM) has been at it again with his famous testing, and has reported temperature variations in the engine compartment as high as 125 ยบ F at the firewall. Mind you, George is working with a V8 in his tests, but the inline 6 can't be that much cooler, and the modern corn gas doesn't care what makes the heat, it vaporizes anyway. Not being familiar with the 6, I'll assume the pump is at the rear as the V8 pump is, so anything that can be done to insulate the pump and fuel lines would help. George made a 1/2" insulating spacer to go un der the pump, and fabricated a pump push rod that much longer, and insulated the fuel line. He also put a similar insulating spacer under the carburetor, and partially blocked the heat riser. GM doesn't post on this Forum anymore, due to his personality differences with some of us, myself included. Look for his findings on the FB. Alan
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| Old Henry | -- 03-16-2012 @ 6:32 PM |
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Because I didn't want to change the stock appearance of my engine compartment with any spacers, insulation, or re-routing of lines but still had occassional vapor lock in similar conditions of driving a ways, shutting the engine off for 20-30 minutes, then not being able to start again, I installed a backup electric pump back by my gas tank to "prime" the mechanical pump on those rare occassions of vapor lock then shut it off. Attached is a picture of my installation. Old Henry (The older I get, the better old looks.)
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| Old Henry | -- 03-16-2012 @ 6:46 PM |
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I believe the vapor lock is at the fuel pump, not the fuel lines, such that insulating them would not help. I determined this by trial and error when vapor locked eventually discovering that if I poured cold water on the fuel pump when vapor locked the car would start. Pouring water anywhere else didn't work. My neighbor that drove flatheads 50 years ago said they used to push a half a grapefruit down on top of the fuel pump and leave it there to prevent vapor lock. Same idea. Cool the fuel pump and keep it cool. While the engine is running and pumping cooler fuel up from the fuel tank the pump rarely vapor locks. But, after sitting a few minutes out in the hot sun with the engine off after driving a ways on a sunny day the pump heats up enough to vaporize the gas and lock it up. Here are some discussions about this on the Ford Barn: http://www.fordbarn.com/forum/showthread.php?t=62701 This is the lengthy, exhaustive thread that ford38v8 referred to: http://www.fordbarn.com/forum/showthread.php?t=61323&highlight=vapor Old Henry (The older I get, the better old looks.) This message was edited by Old Henry on 3-16-12 @ 6:49 PM
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| supereal | -- 03-17-2012 @ 5:54 AM |
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Hard starting when hot is, more than, usual an ignition problem. If pouring water, etc, on the fuel pump seems to help, I'd suspect a weak or damaged fuel pump. A cracked diaphragm or leaking valves can be diagnosed with a fuel pressure test. It is true you can't pump non liquid fuel, but the vaporization has to occur between the tank and the pump for it to cause loss of prime. Run a hot engine compression test, as well. You may discover that it drops significantly, making restarting difficult. As old Henry said "diagnose, don't guess".
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| kubes40 | -- 03-17-2012 @ 6:08 AM |
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Super, You and I know this topic has been argued since these cars were new. I am confident the argument will continue. What I am also confident of it IF the car is set up correctly, there will be no "vapor lock". I know this from experience. Kind of reminds me of all the guys that add HUGE battery cables,extra grounds, relay by-pass switches, 8v. batteries, etc. to get their cars to turn over better. Yeah, those things help but they also mask the true problem(s).
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| supereal | -- 03-17-2012 @ 6:50 AM |
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After years of chasing problems in old Fords, I sometimes suffer from "knowing too much", Mike. A couple of years ago, my car would buck, and sometimes stall, and the electric pump would cause it to smooth out. Easy, I thought, bad mechanical pump. Nope. Replacement didn't cure it. Ignition open or short? Same result. My fuel pressure at the carb was fine. The only part of the fuel system that wasn't suspect was the line between the tank and the fuel pump, out it came. I quickly discovered that I couldn't force compressed air thru the line, so I straightened it out and tried to force a wire thru it. Out came lots of rust and dirt! The internal coating had failed, and the steel line was clogged, and occasionally plugged! This seemed odd, as the fuel pressure was OK. Then, I Recalled what an old well driller had told me years ago: pressure doesn't mean quantity! Twenty bucks worth of new line made the car like new, and my " vapor lock" was history. It is way too easy to overlook the obvious when looking for the cause of a problem. When you test pressure,, don't overlook measuring quantity.
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| TomO | -- 03-17-2012 @ 8:15 AM |
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Kube and Super, I am with you guys 100% on this subject. Ewaters should first check to see if there is any gas in the carburetor when it is hard starting. If it doesn't have any gas, repair the carburetor. If there is gas, check the spark for a nice blue spark, 1/2" long at idle with the engine at normal operating temperatures. If the spark is weak, check the coil and condenser. The fuel pump should deliver 2 1/2 - 3/1/2 lbs pressure on the output side. It should be able to develop 10" of vacuum and the vacuum should either hold or slowly decrease to 0 over a minute. Tom
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| Norm | -- 03-17-2012 @ 11:25 AM |
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The fuel pump on the "H" series flat six is forward and low on the engine, not up high and near the firewall as on the V8. I have a truck with the gas tank behind the seat, but even in a car the pump suction may still be flooded (i.e., the pump at the same height or even lower than the tank). IMHO an electric pump would be a waste of money. Try disconnecting the fuel pump inlet to see if gas flows out (this will also diagnose a clogged line). My '48 truck with this engine has none of the problems described. When hot it will start with just a touch of the starter button. Are you flooding it when starting hot? It shouldn't need any choke or accelerator pump to start when hot. Try starting without doing anything but hitting the starter. This engine uses a regular cylindrical coil and the distributor is just like the 8BA V8 (except the cam has only six lobes!). When I had symptoms something like this I finally tracked it to a bad condenser. Norm
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