Author Topic: Same old issue discussed many times......but want to ask again.  (Read 1037 times)

Offline Jim Miller

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Re: Same old issue discussed many times......but want to ask again.
« Reply #20 on: September 27, 2017, 08:03:59 PM »
I'm new at this and read the forum every evening - to avoid doing something stupid! Out of curiosity I crawled under my '41 for a closer look and I have the same arrangement as in Bill Ingler's photo. But I have not used the electric pump at all. Even during some 90 degree weather recently. Around the Great Lakes we can get marine gas which ranges from 89 to 91 octane and no ethanol. I use lead additive and 4oz of Marvel Mystery per 10 gallons. I also have a 50 year old wooden boat with a big Chrylser V8 in a tight engine box and no issues ever. I think it's because of the non-ethanol gas.
Jim Miller
Jim Miller

1941 62 sedan
2016 SRX

Offline robert G. smits

  • R. Smits, CLC 2426
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Re: Same old issue discussed many times......but want to ask again.
« Reply #21 on: September 29, 2017, 06:53:32 PM »
All of you guys who are against an electric pump must not tour with your wife.  I do not look forward to sitting in an intersection in 100 degree weather with my wife in the passenger seat for 15-20 minutes.  Been there.  I would also contend that the 346's are markedly different from the OHV engines.  I don't think I ever experienced a vapor lock when I lived in Iowa although it gets to 100 there also.  I have toured 5500 miles with the 41 since installing the Airtex pump and have probably only used the electric 6 times other than starting after sitting for an extended period.  I never have to run the electric for more than 30-60 seconds. I do not have an accessory pump on any other car.  Just my TCW.  Bob Smits #2426
R. Smits, #2426
23 Cad 7P Touring
32 Cad 5P Coupe
38 Cad 90 Series
41 Cad 63 Series
58 Cad Eldo Barritz
The average man can take care of one Woman and two Cadillacs, Al Edmond AACA Past President

Offline lexi

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Re: Same old issue discussed many times......but want to ask again.
« Reply #22 on: September 29, 2017, 09:27:55 PM »
Good one Bob! My wife won't get in my car (hates that 'old car smell'), but I do not like being stranded in intersections either. I had a '56 Caddy that must have vapour locked on me about 200 times over the course of 7 years. Very frustrating and potentially very dangerous. I am fortunate that my current '56 has the dealer added 6 bladed fan which I think has saved me thus far, but on numerous occasions vapour lock was certainly developing. Although I am a purist, I did install an electric fuel pump for safety reasons, but did so keeping the OEM mechanical pump installed. As member Art Gardner recently told me, an open hood of a running '56 will "melt your face off". He is correct. Some of our cars are just not hot weather friendly and '56's are known to run 'hot'. All Cadillacs are not created equal, nor do we all live in the same climate with the same fuel available. Copied below are portions of 2 earlier posts of mine on what I did for those who are interested:

Myself and some other members use a separate dedicated fuel line for the auxiliary electric pump. I have a toggle switch for it, that is also connected to the ignition switch, so it can only be turned on when the ignition switch is on, for safety. So when the car is shut off it is also off, (no running pump & fire hazard). When the car is on it can be turned on or off. Mount e-pump near fuel tank and 'T' off main fuel line there to feed your new line (with the electric pump). That line can follow the main fuel supply line but then by-passes the mechanical pump when it reaches the engine bay, (thus avoiding much of the engine heat). This parallel by-pass then "T" connects to the factory fuel line between the carburetor and mechanical pump. There is also a fuel filter at the electric pump. Therefore, the electric pump can be used as required (especially to fill carb bowl to expedite starting after long periods of inactivity-saving your starter motor), or turned on to combat vapour lock. I agree that it should be mounted as close to the fuel tank as possible. I have run the car this way for 2 years without a problem, using the OEM pump alone or both running simultaneously. Both rated for same pressure so as not to damage carb/flood engine. This set up assumes that you are keeping your mechanical pump in operational condition.  

Note 1: Should you wish to NOT use your OEM pump in conjunction with the electric, please search this Forum for additional posts detailing what members have done to accommodate this procedure.
Note 2: Air entering the system can greatly lower the efficiency of your pump. I had an air leak at my mechanical pump's strainer nut which caused all sorts of grief until fixed. As this was an 'air-suction-leak', no gasoline was noted weeping from the system-just air entering into the pump and causing fuel starvation problems. So a visual inspection did not detect it. A pressure test did however reveal this air leak, which mimicked vapour lock.

Clay/Lexi
« Last Edit: September 29, 2017, 10:33:16 PM by lexi »

Offline 76 cadillac bob

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  • Name: Bob landre
Re: Same old issue discussed many times......but want to ask again.
« Reply #23 on: October 08, 2017, 12:41:06 PM »
For what its worth? Go back to the year when the cars were built. Was vapor lock such an issue then? and why now? yes parts wear out, but rather than reinventing the wheel is there no way to fix with out adding on or altering the original design or was it bad then as well? I dont remember. My 76 seems ok without having to tweak the fuel lines or fuel pump. Luckily it is outside the tank, and although pumping the pedal is normal for this car when cold, it does start right up once warm. Just curious. Tweaking  anything on these old cars could create more issues. I found out the hard way with my suspension.
Long story......
CB

Offline Jeff Rose CLC #28373

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Re: Same old issue discussed many times......but want to ask again.
« Reply #24 on: October 08, 2017, 03:37:28 PM »
For what its worth? Go back to the year when the cars were built. Was vapor lock such an issue then? and why now?

It wasn't a design problem.   The problem just simply did not exist back then. We are not using the same fuel as they had back when these were built.
Jeff
« Last Edit: October 08, 2017, 03:39:30 PM by Jeff Rose CLC #28373 »
Jeff
CLC #28373
1970 Coupe DeVille
1955 Series 62

Offline Bill Ingler #7799

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Re: Same old issue discussed many times......but want to ask again.
« Reply #25 on: October 08, 2017, 04:22:52 PM »
The problem of vapor lock did exist back then. Attached is from the Cadillac Service Man July-August 1944. Even the fuel used in those early days could and did cause some vapor lock.   Bill

Offline Rob Leech

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  • Name: Rob Leech
Re: Same old issue discussed many times......but want to ask again.
« Reply #26 on: October 08, 2017, 08:20:23 PM »
I also think you have an air leak. While the engine is cold, wrap a shop rag around an air hose. Use a shop air compressor, not one of those tire fillers from Walmart. Hold the rag tightly into the fuel filler tank neck and pressurize your fuel tank. Your leak will show up. If the engine is hot the fuel may evaporate before you can find it.
Rob Leech 1956 Eldorado Convertible

Offline jdemerson

  • 1952 Cadillac 6219X Vermont -- Emerson
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Re: Same old issue discussed many times......but want to ask again.
« Reply #27 on: October 10, 2017, 06:27:34 AM »
The problem of vapor lock did exist back then. Attached is from the Cadillac Service Man July-August 1944. Even the fuel used in those early days could and did cause some vapor lock.   Bill

Bill, thanks for posting this 1944 Cadillac Service Man article; it is fascinating. Front and center is the temperature at which gasoline boils -- there's a clear implication here that we should avoid fuel with ethanol where that is possible (even though that was hardly an issue in 1944!). The article clearly supports the kind of advice that good CLC members like Jay Friedman, Scot Minesinger, Jason Edge, James Landi and several others have provided. Use gasoline with as high a flash point as you can find, eliminate any and all leaks, and insulate lines where possible. It's fascinating, but still not surprising, that Cadillac had it right in 1944...

John Emerson
1952 Cadillac Sedan 6219X
John Emerson
Middlebury, Vermont
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1952 Series 6219X
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Offline gary griffin

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Re: Same old issue discussed many times......but want to ask again.
« Reply #28 on: October 10, 2017, 10:59:47 AM »

I  have been studying this phenomena since the early 1950's.  I made a stew on a boy scout hike  and the potatoes did not cook thoroughly.

Simple physics. We need the gasoline to evaporate and mix with air to combust and run our engines. The boiling point of liquids is a variable depending on temperature and pressure.  My potatoes did not cook because  of altitude causing a low pressure and lowering boiling point of water.  Premature evaporation (AKA vapor lock)  is because the fuel pump sucks the fuel from  the tank thereby lowering the pressure in the fuel line.  The lowering of pressure along with higher temperatures and variable boiling points due to various gasoline formulas creates a great environment for premature evaporation. 

We have no control over ambient temperature other only driving on cool days.

We have little control over gas formulation other  than choosing where we buy our gas and using additives to control boiling points.

Solutions are to protect the fuel system from engine heat until carburetor induces evaporation or change the pressure in the fuel system typically with a pump near the tank in the col undersides of our cars.
Gary Griffin

1940 LaSalle 5029 4 door convertible sedan
1942 Cadillac 6719 restoration almost complete?
1942 Cadillac 6719 (parts car) (Gone)
1957 Cadillac 60-special (Needs a little TLC)

Offline The Tassie Devil(le)

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Re: Same old issue discussed many times......but want to ask again.
« Reply #29 on: October 10, 2017, 05:15:50 PM »
Bill, thanks for posting this 1944 Cadillac Service Man article; it is fascinating. Front and center is the temperature at which gasoline boils -- there's a clear implication here that we should avoid fuel with ethanol where that is possible (even though that was hardly an issue in 1944!).  John Emerson  1952 Cadillac Sedan 6219X
Back in 1944, could there have been a problem that arose out of the deficiencies of supply during WW2.   Could they have been diluting the fuel available to the masses, and saving the good stuff for the war?

Bruce. >:D
'72 Eldorado Convertible (LHD)
'70 Ranchero Squire (RHD)
'74 Chris Craft Gull Wing (SH)
(Past President Modified Chapter)

Offline gary griffin

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Re: Same old issue discussed many times......but want to ask again.
« Reply #30 on: October 10, 2017, 06:01:08 PM »

I think fuel was not substandard but it was rationed. 45 years ago I was taking flying lessons and an old guy on the crew told me there was aviation gas available with  no rationing during the war because the government figured it may need civil aviation in case of invasion. Old guy told me he would fill gas cans at airport and land in his pasture with 2 or 3 Jerry cans (Old G I,  5 gallon cans) and be good for gas to drive to the shipyards and weld on war ships for the week.
Gary Griffin

1940 LaSalle 5029 4 door convertible sedan
1942 Cadillac 6719 restoration almost complete?
1942 Cadillac 6719 (parts car) (Gone)
1957 Cadillac 60-special (Needs a little TLC)

 

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