My 1946 Cadillac will start up very well when cold and in lower temperature, however when the temperature is above 75 or when idling for a long time, like in a parade my temp.gauge will creep up towards the hot side, but will not boil out the antifreeze. water temp in radiator reads 200 with a manual thermometer. I have an aux. elc fuel pump that will clear out the bubbles in the fuel bowl but the car will not start for about 20 to 30 minutes. I was wondering if the fuel in the carburetor could be boiling and also the fuel in the intake manifold be evaporating from the present type gas What would be a possible cure for this? I am using 1 optima batt. and am thinking of using 2 optima batts wired in parallel,with the thought that 1600 cold cranking aps wiil turn the motor over a little faster and possibly cure my starting problem., also I saw an article by Walt brewer that mentions using high output starter coils has anyone used these high output coils and did they help the starter turn over faster?Any input would be very much appreciated.
Dave T CL22554
Hi Dave,
I see the very same thing with my 48...Bubles in the fuel bowl.
Starts up in a snap when cold. But takes a few cranks when it hot.
I put two Optima batteries in parallel ..they fit perfectly in my battery box. I never have a problem with slow cranking....it definitly cranks more when warm...but has never failed start within 15 seconds of the first crank.
(If you decided to go with dual Optimas, email me privately and I'll show you what I did to hook them up).
I did Not use higher output coils.
Is your problem slow cranking when hot??
Vic
Sounds like the fuel is "boiling" that would cause vapor lock. Today's fuels with ethanol added
have a much lower boiling point than the old formulations -- thus, they are more prone to
creating problems like this in our old cars that were never designed to run with this stuff.
The electric fuel pump normally helps solve this. Why it takes 30 minutes to work
for you I don't know -- perhaps an issue with letting the temperature cool down.
I don't know which state you live in, but in some places gasoline is still available without
ethanol and that's what you need. Here in western PA we can still get an unadulterated
gasoline but it's getting harder to come by.
Another approach is to add a product like "Max Lead 2000" which contains tetraethyl
lead. That will increase the boiling point by about 10 degrees or so and will help eliminate
this problem. At the same time, it increases the octane rating. Check the internet for
sources. One is:
http://www.jackpodellfuelinjections.com/maxlead.htm
Mike
You are experiencing the classic vapor lock and as stated the ethanol in today's gas boils at a much lower temp and the exhaust manifold on a flathead boils the fuel in the line to the carb and if you feel the carb it is probably hot as Haiti. The electiric fuel pump will help getting the gas thru the fuel pump but it still vaporizes in the fuel line to carb and in the carb.
I had a 48 with exactly the same problem and partially helped it by buying a lenght of neoprene hose used in aircraft engines and slit it and placed it around the pump to carb fuel line which helped prevent the exhaust manifold from heating the fuel line. The old trick of wooden clothes pins clipped to the line also helps dessipate the heat. If all else fails carry a cooler with water and ice and a rag in the trunk and when you vapor lock get the rag, soak it in the ice water and wrap around the fuel line to cool it and the engine should run until it vapor locks again. Try to avoid gas with ethanol and you will be better off. The higher the octane the gas is the sooner the vapor lock so get lowest octane you can get if ethanol is in the gas
Herman,
Reading your post prompted the recollection of my Dad's home-brew cure for the same problem on a Jeep that had been converted to a real death trap by the addition of a 383. Clothes pins, but in addition they were clamping aluminum foil around the steel line from the fuel Pump to the carb. I assume the foil was to enhance the heat dissipation. Kind of the opposite approach from insulating the line, but it did seem to work.
Mark Lowery, CLC #25216
Dave T,
I assume the engine cranks over OK. Do you try to start it as a flooded engine? As you may know when starting a flooded engine you hold the throttle wide open. This helps clear the gas out of the manifold.
If that helps the starting problem then you know it’s a fuel problem. Otherwise it could be an electrical problem.
Glen
Are you using big enough battery cables? They should be "00" cables. Today's narrow cables will not carry the voltage load you need on a 6volt '46. Try them if you have the modern size cables. I've cured a couple of 6 volt cars from no hot starts this way.
Dave,
Where is the electrical fuel pump located ? It should be below fuel level in the fuel tank, as close as possible to the tank (say, bolted somewhere on the frame below rear door sills) and as far as possible from exhaust system. If not, it could pump only air in case of vapor lock.
If its location is correct, it may (reversely) flood the engine. Then, try following Glen's advice.
I would like to "second the motion" re: John Polychron's advice to make sure you are using 00 size battery cables.
Similarly, I suggest you make sure all your grounding points are clean and free of corrosion. This includes: 1. Scraping off any paint and corrosion there might be between the starter motor and the place on the block it bolts to; 2. If I remember correctly, a '46's negative battery cable (ground strap) is bolted to a nearby place on the frame. Make sure the bolt and the place on the frame is clean and free of corrosion and paint; 3. Make sure the attachment points of the small ground strap from the motor to the firewall are clean and free of corrosion.
If we're talking about the starter, Doug recommends an extra grounding stud (bolt) on the commutator end of the starter. :D
http://www.cadillaclasalleclub.org/forum/index.php/topic,64722.msg64856.html#msg64856
http://www.cadillaclasalleclub.org/forum/index.php/topic,61365.msg61388.html#msg61388
Yikes! The "Vapor Lock Club" is growing thanks to the ethanol alcohol in the gasoline. I have a heat resistant material that I wrap the fuel pump, filter, and lines with. I take it off at shows. I like the neoprene hose idea because it is neater. My application looks pretty messy but it works. I also changed out my thermostat. I was unsure how well it was working, and I had not changed it since getting the car 6 years ago. My 56 Fleetwood requires a 180 degree thermostat, and it was about the easiest thing that I had to work on with this car. I notice an improvement with lower temperatures driving in the 92 degree heat yesterday. I was just below 1/2, which is about where the engine should be running. Make sure to replace your paper gasket as well. Don't put booster additives in the tank because they are alcohol based. You will be surprised when you read the labels.
I also add Seafoam to the gasoline to stabilize it as it sits a bit (especially in the Winter). I think that this helps a little as well. Good luck and stay cool driving!
Don't put booster additives in the tank because they are alcohol based.
You will be surprised when you read the labels.
Some do and there are a few that don't contain ethanol. Read the label and decide
for yourself. Also, all alcohols are not created equal -- ethanol (which is the main additive
we're talking about here) is not the same as isopropanol, for example.
As I stated in my earlier post -- if possible -- avoid fuel with ethanol added. Some
states require posting at the pump such as "CONTAINS 10% ETHANOL" and some
do not. It's worth checking around as to the regulations where you live.
Mike
Up date I appreciate all the interest that I received concerning this issue, What I have done is put two optima 850 amp batts together in parallel that gave me 1700 cold cranking amps that seemed to turn the motor over faster and I would hold the gas pedal down just slightly and the motor will start up ,no problem. I did find optima batts that had 950 cold cranking amps if needed. As for the bubbles in my fuel bowl I don't quite understand what is causing them I put a laser thermometer on the fuel bowl and temperature is only 150 to 160 degrees, that would be to low to boil, when car is first started there are no bubbles,I have wiggled the rubber fuel line to see if bubbles start when moved, also when I turn on my elec fuel pump the bubbles clear out, I was thinking that air was entering the fuel line someplace ,.but if that was the case I would have bubbles all the time so I am still trying to figure out the bubble situation.
Dave T CL22554
Gasoline boils at a much lower temperature than water. While water will boil at
212 Degrees F, our new 87 octane gas will boil as low as 85 degrees. This is
why you noticed the "boiling" and resulting vapor lock.
This assumes that the fluid is not under pressure and at standard sea level altitude.
Alas, the "old" gasoline formulations without ethanol that used tetraethyl lead (TEA)
where much better (boiled at higher temps). Gasoline without ethanol is still available
is some states, whereas tetraethyl lead usage is restricted to 100+ octane avaition gas,
racing purposes and some marine uses.
TEA can be purchased as an additive, however.
Mike
Mike
Has any body ever considered the idea of adding a gallon of kerosene or diesel fuel to a tankful of regular to raise the boiling point? I have read that these fluids have higher boiling points that gasoline, in fact, that is how they are seperated out in the refining process.
I have been thinking of trying this in my 1940 LaSalle. It might be easier to modify the fuel than to modify the car.
Any thoughts?
Kerosene and / or diesel fuel do have a higher boiling point. However, they
will crud up your spark plugs, carb, etc. and lower the octane rating of the fuel in
your tank. Plus, I think you would have to add more than a gallon in a 20 gallon
tank of gas to have the needed effect on the boiling point.
It doesn't sound like a good idea to me.
Mike
QuoteAs for the bubbles in my fuel bowl I don't quite understand what is causing them I put a laser thermometer on the fuel bowl and temperature is only 150 to 160 degrees, that would be to low to boil, when car is first started there are no bubbles,I have wiggled the rubber fuel line to see if bubbles start when moved, also when I turn on my elec fuel pump the bubbles clear out, I was thinking that air was entering the fuel line someplace ,.but if that was the case I would have bubbles all the time so I am still trying to figure out the bubble situation.
Dave T.
I think you have a leak between the electric fuel pump and the mechanical pump. When the mechanical pump is running by its self it sucks air in through the leak. When you turn on the electric pump it pressurizes the line so the line does not pull air in. But the leak may not let fuel out or the leak maybe so small it is not easily seen.
The first suspects would be rubber hoses, next would be the flare nuts.
Glen
Glen . If I would have a air leak in the fuel line wouldn't I have the air bubbles before the motor warms up?
Dave T
I personally do not think an air leak is the problem here. The bubbles go away
when you turn on the electric pump because you are putting the gasoline under
additional pressure.
When you put a liquid under pressure, the temperature at which the liquid will boil
goes up (this is the max temperature it will go to). This is standard physics.
Remember Mom's old pressure cooker? It cooked things faster because instead of the
water boiling at 212 degrees F as it normally does, the water was able to get up to 250
degrees or so due to being in a pressurized container. Same idea.
Mike
Mike,
I am aware of pressure cookers and how boiling points go higher with pressure. I spent a lot of time with relatives in the Colorado Rockies. My father’s 38 Cadillac has an electric fuel pump and he made sure I knew why it was there.
Dave T.
I interpreted your comment “when car is first started there are no bubbles†to mean within the first few seconds after starting.
Generally speaking when fuel gets hot enough to boil you get large bubbles and the fuel pump “locks up†and can not pump fuel. I’m not sure why only a small amount of fuel would flash to vapor in a line with lots of fuel at the same temperature and pressure.
It is also possible air leaks can open up with heat and close again when it cools off.
It’s another avenue to pursue.
Glen
Dave T.
Another thought: What happens to the bubbles you see? If the bubbles collect in the bowl getting larger until they force most of the fuel out, then they are most likely air. If they move to the top and the large bubble at the top never seems to get any bigger then the bubbles are fuel vapor. Now on the pressure side of the pump they condense back to liquid.
Does that make sense to everybody?
Glen
Dave, I have the exact same problem with my 1939 LaSalle. Did you get your situation resolved? Sk
Don't totally rule out the contribution of faulty hose to the air bubbles until you make certain you are using Fuel Injection grade hose (SAE 30R9). The old hose we used for years (SAE 30R7) is not ethanol resistant and will deteriorate over years of ethanol exposure. During the 2010 Sentimental tour in Texas I was having vapor lock issues and noticed the air bubbles in the fuel pump. The electric emergency pump also quit working(again a ethanol problem in a 7 year old pump) I removed the old pump and installed fuel injection hose and was able to complete the next 4 days of the tour with only mild problems. The same goes for fuel pump diaphragms. If you rupture your diaphragm and are using an emergency electric pump you will full your crankcase with gasoline. It is getting to the point that I am considering going to electric only systems on my touring cars.
Bob Smits #2426
In Arizona we have no choice on ethanol it's 10% or nothing. 10% will flash off(boil) in winter at 105F and summer at 145F. With fuel components running at @150 +, you can see the problem. I have been adding 1 qt of kerosene to 10 gal of 87 octane in my Hudson( 50 Caddy has no problem) to avoid vapor lock but I feel it doesn't do much. BUT, sleeving the fuel pump lines, incoming and pump to carb, with mylar definitely had an effect. I also placed a mylar pad between the fuel pump and the exhaust manifold. This is a concern area on flatheads. You can use a gauge to test for pressure and suction if you think there is an air leak.
there are comercially avail thero sleeves for fuel lines
the new fuel is crap lilke everyone else is saying
there is a website, puregas.org i believe that lists gas stations that still have gas with additives like ethanol in them anywhere in north america
the idea if using an electric pump to back up a mechanical pump is not the best idea
most electric pumps do not allow fuel to free flow through them while they are not running
also the pressure from a electric pump may burst the diaphram and fill engine with gasoline
i just replaced a suspect mechanical pump on my 62 cadillac with an electric mounted close to tank outlet as possible,that is where they should be mounted,they push fuel,not suck it
as far as originality is concerned, you can remove pushrod from mechanical pump and leave there for looks,and run a new hidden fuel line to the carb to run the motor
i would rather be running and not original than not be able to use the car because of vapour lock
to me a car that doesnt work right or has to be babied is not worth owning.
i was towing a wood chipper behind my cadillac tonight down the highway.i
treat it just like any modern car,i added disc brakes to stop the beast,now electric pump and i use it like a truck to haul anything, anywhere