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John_Mereness

What are the trick to vapor lock prevention for a 1929 Lincoln ?

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Hello,

Friends have a gorgeous original 1929 Lincoln L 5 Passenger Touring and were telling me today at lunch that the car is totally unusable in weather above 85 degrees. They asked if I knew any tricks SPECIFIC to a 1929 Lincoln. I know it is a fairly popular car I CCCA, so I thought I would ask. So, thus this post.

Thank you,

JMM

John Mereness

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Are you sure that the coil is in good condition? A bad coil behaves the same as vapor lock. Perhaps Skip Haney in Fla could rebuild it. Give him a call and see if he will handle it.

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I take a stab at it, be aware I've never worked on a '29. My 38 Zephyr has a fiber block about 3/4" thick between the carb and intake manifold. It's purpose is to thermally isolate the carb from the intake. Does the '29 have one? Is the fuel supply line routed away from engine heat? If not then move it till it is. Let us know.

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Does your Lincoln have the vacuum tank or a fuel pump?

A fuel pump should work better in heat than the vacuum tank in controlling vapor lock. The extra pressure raises the vapor point of gas.

You may get better answers on the Lincoln Owners Club Forum. It is for the model "L" and "K".

http://www.lincolnownersclub.com/content.aspx?page_id=2153&club_id=546775

Your car should run fine in the hotter weather if it is not overheating.

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I am a purist about these cars, I strictly adhere to the mantra, "as Henry made it" with one great exception...I have a 6 volt electric pump hidden under the car at the tank to be utilized on those occasional "out of town with the wife in 98 degree weather for momentary fuel starvation emergency" operated my a momentary switch...I suspect it is due to the location of the fuel pump..up top as opposed to later designs low and more exposed to air draft from driving..

...I have checked temps under hood and carb and fuel pump are well over 125 degrees on normal hot highway drive..I have minimized this issue, but never, i'm ashamed to say, eliminated it..so the xtra pump is like a spare tire...hope to not need it but happy it's there..My issue is usually driving along, stop for the wife for whatever, 10 min, back in car, starts, drives away then runs out of fuel...kick on pump..drive for a minute, turn pump off.. chk for--

-clean air tight lines to pump and tank

-clean tank, pickup and filter

-clean non leaking carb and float

-efficient functioning cooling system / radiator thermostat

-engine timing and ignition in spec.

(yes a coil failure can cause stalling, but we are discussing fuel flow)

I have tried some of the silly old wives solutions, clothes pins, thermal wrapping on underhood fuel line etc, no help...I do try to keep tank full of cool gas on hot days ...

Edited by Mssr. Bwatoe (see edit history)

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Hello,

Friends have a gorgeous original 1929 Lincoln L 5 Passenger Touring and were telling me today at lunch that the car is totally unusable in weather above 85 degrees. . . .

JMM

John Mereness

Hi John ---- Don't know if you remember me from the Franklin Club (I met Mike a couple of times), but back then I had a 1925 Series 11 Franklin Touring with a similar problem. When hot, especially in hot weather, if the car was shut off for a short time or if it stalled, it would not start. On one occasion when a friend drove and messed up, we sat roadside for half an hour with the hood up.

What I learned is that if I started the engine cranking with the ignition off, and cranked for maybe 5 seconds, and THEN turned on the ignition (with the engine still cranking) the car would always fire right off.

What's happening is that when the carburetor is hot, which it gets in a Franklin and an original Model L Lincoln, and the intake manifold cools a bit, raw gasoline is drawn up from the carburetor creating a rich condition. So you are trying to start a flooded engine. Why it doesn't clear itself I'm not sure, but if you crank witih the ignition off, you can clear out all of the super-rich mixture until a proper mixture is present, and it will fire. Exactly why this all works, I'm not certain, but I've done it on every old car with success.

With Wilkinson-era Franklins and brass cars with dashboard needle-adjust carburetor control, I always shut the engine off by closiing the needle valve and not by shutting off the ignition. Then when I start, I crank with the needle still closed. As soon as it fires, I open the needle valve to the proper setting. Works every time.

I'd be really curious is this works on a Lincoln --- crank with ignition off, that is.

--Scott Dwyer

1914 Franklin Series 5 Touring

1924 Franklin 10-B Sedan

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I dont like modifying old cars very much, but the lincoln in some cases will be a bear to drive with the vapor lock issue. First, I would try everything I could before modifying the car. The carbs are 90 years old. Make sure it is 100% working. Make sure your float adjustment is correct. Have it rebuilt if you think there is anything wrong with it. I would take the fuel line off that goes between the carb and the firewall and insulate it. I have seen people wrap them in foil and "successfully" cure their vapor lock issue. Some people prefer a modern exhaust wrap material. I would make sure that the radiator bellows are working and adjusted properly so that the engine is cooling. I often will open the hood of the car as soon as I shut it off to help cool it so that it wont vapor lock.

Lastly on the list of things to try before modification is to use the best gasoline you can find. Some states allow premium to be sold without ethanol. If you live in one of those states, you are lucky. research and buy the lowest ethanol content fuel that you can. I use premium from chevron in california. I have the best luck with it but still have the occasional issue. Also, though a pain to do everytime, you can shut off the fuel valve under the dash and let the car run out of fuel when you stop. That way, there is no gasoline in the carb that will boil when you are parked.

If nothing else works, you will probably want to install an electric pump. Do not cut any of your fuel lines to do it. Make a new set of two lines to replace one line and use the pump and some fittings to join the new two lines together. That way you can preserve your original lincoln fuel line for the future. If that does not seem to work very well, you can put the pump in place of the fuel strainer on the frame as long as you find a way to put some other kind of filter in the system somewhere else. As a last resort you may be able to bend a line to install the new pump. I really encourage you to avoid cutting it. If you have to, do it somewhere that you cannot see it. Mine was cut in the engine compartment and I have a brass union there now. I dont think I will ever find an original line to eliminate that stupid union. It looks bad.

There is also a down draft conversion kit that was made for lincolns in the 60s. It was available from the dealer (I think) and had a lincoln part number. If you can find one of those kits, you will get the carb out of the valley between the manifolds. This is the best (as in it fixes the problem, not as in a purist will like it more) solution.

Also, you are not clear whether the issue is that the car will not restart when hot or that the car will not run properly when hot. Some of these will work for both of those problems I guess, but they are different problems.

Edited by Linus Tremaine (see edit history)

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As the owner of three 1920s cars with vacuum tanks, I have been reluctant to add an electric fuel pump because the needle valves and seats probably cannot handle more than 1.5 psi. Of course, one could add a fuel pressure regulator just before the vacuum tank.

The following have worked for me:

1. Insulate the fuel line between the carburetor and vacuum tank. I have used a product called Cool Tape, sold at performance stores, spiral-wrapping with 50% overlap. Leave approximately one inch from each end fitting uncovered to allow the fittings to be released and to slide back. I then cover the cool tape with asphalted, "corrugated" loom material for a period look.

2. I have made heat-resistant "blankets" to wrap around the vacuum tank, securing them with Velcro. I used Thermo-Tec "Aluminized Heat Barrier" part no. 14001, which is a 36" x 40" sheet--which will make up to SIX vacuum tank blankets (my cars' blankets start with 10" x 20" and are trimmed to fit well). These can be removed quickly for show and can be reinstalled almost as quickly. Perhaps a lesser-size sheet is available, but this was the only suitable size available at my local performance parts house. Thermo-Tec's website is www.thermotec.com Design your blanket to protect the vacuum tank reservoir from exhaust heat, and this will usually include the bottom of the vacuum tank.

3. My three vacuum-tank equipped cars are inline sixes, each with the exhaust downpipe at the front of the engine. Same is true of my 1930 Pierce (an inline eight), which has a mechanical fuel pump rather than a vacuum tank. The idea of this design was to use radiant heat from the radiator and the exhaust downpipe to WARM the updraft carburetors to compensate for the limited volatility of the fuel of the day. Today we have exactly the opposite situation, in that 10% ethanol gasoline is "too volatile" for low-pressure fuel systems. A Skinned Knuckles article of a few years ago claimed that 10% ethanol fuel will boil (i.e., vaporize) at 182*F underhood temperatures. I have had the greatest success in reducing vapor lock by wrapping the vertical exhaust downpipe with asbestos-substitute material in sheet form. I bought mine from Restoration Supply www.restorationstuff.com and it has the general appearance of the asbestos wrap used before WW2. I do not care for the appearance of the spiral-wrap material often used on headers. This downpipe wrap has the effect of reducing the heat pushed against the carburetor. I don't recall the exhaust configuration of the Lincoln L series V8s, but I suggest you apply the concept of reducing exhaust heat within the engine compartment, and especially reducing exhaust heat directed at the carburetor.

4. Finally, to me an essential piece of equipment is a supply of cloths and water (a beverage cooler is helpful) to help condense vaporized fuel in the vacuum tank and the fuel lines if and when the above measures are insufficient.

Edited by Grimy
correct URL + clarification (see edit history)

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Yes, the car has a vacuum tank and it also has a carb that really is only designed for gravity feed - an electic fuel pump is something to be avoided (I have seen and heard of too many people having fire issues).

Carb sits in the Vee in the engine as well - updraft.

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I think you need to find some creative way to shield the carburetor from exhaust manifold heat, perhaps a sheet metal heat sink and perhaps also some heat barrier material. It will be difficult given that the exhaust manifolds are in the Vee and are close to the carburetor.

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There have been a couple of solutions posted that you can try. There is also a post in the CCCA Forum about curing vapor lock with a vacuum tank. They show a fairly safe way to install an electric fuel pump by bypassing the vacuum tank.

If you would post the type of problem and the conditions that it occurs under, a solution more suited to your situation may be posted.

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