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Vapor Lock 1948 Cadillac

Started by 48ragtop, August 09, 2011, 12:28:32 AM

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48ragtop

I've found a company that makes finned tubing and can custom fabricate tubing for fuel lines.  I was curious if a finned gas line would help dissipate heat and thus aid the vapor lock problem.   I'm not sure if it would help or possibly aggravate the problem by picking up yet more ambient heat and transferring it to the fuel.   Has anyone explored this option?

Energy Transfer - MDE in Carrollton, OH

Ed Wisniewski
CLC No. 26482

Edward M. Wisniewski, CLC #26482
1948 Cadillac Series 62 Convertible
1957 Chevy Belair Convertible
1982 AMC Eagle SX/4
2007 Chrysler Crossfire

Tom Magdaleno

Have you tried the old school way of putting clothes pins on the fuel lines?  The wood takes away the heat.
Tom
'38 Cadillac V16
'71 Buick Riviera
'65 Chevy Truck
'56 Packard Super Clipper

jaxops

Ed,

  It became more and more of a problem for me as alcohol became "mandated" througout the year.  I use Seafoam additive to help eliminate the water in the fuel that comes with the alcohol and counter-act some of the reduced attributes of the ethanol fuel.  It does help, but I also wrapped my  fuel pump. fuel lines, and fuel filter with heat resistant aluminized wrap.  With that I run about normal temperatures, unless I turn on the AC and it is a very hot day (as it has been lately). 

Mark Monaghan
1970 Buick Electra Convertible
1956 Cadillac Series 75 Limousine
1949 Cadillac Series 75 Imperial Limousine
1979 Lincoln Continental
AACA, Cadillac-LaSalle Club #24591, ASWOA

Dave Shepherd


Philippe M. Ruel

Quote from: 48ragtop on August 09, 2011, 12:28:32 AMI was curious if a finned gas line would help dissipate heat and thus aid the vapor lock problem.   I'm not sure if it would help or possibly aggravate the problem by picking up yet more ambient heat and transferring it to the fuel.
A finned tube will help "heat exchange" between inside and outside the tube.

It will dissipate heat if heat is inside the tube (e.g. an automatic transmission cooling line). If heat is outside, finned tubing will help heating the fluid inside as you guessed. This is not interesting (understatement) for a fuel line.

Line insulation will help for a while.
Other helping devices :
- an electric fuel pump, which will put fuel "under pressure" and retard its evaporation.
- better engine compartment ventilation, using a more powerful fan (like Flex-a-Lite).
1952 60 Special in France.

pauldridge

I had serious undriveable vapor lock issues with my '40 60S.  Even just driving down the road at cruising speed, I'd get vapor lock and be stranded.

I added an electric fuel pump near the tank, chose one with 3-4PSI output, and I haven't ever had another problem with vapor lock since.  This in 105 degree Texas heat.  I can drive the car hard at highway speeds, park it, come back and see the fuel literally boiling in the fuel pump glass bowl, get in, and she cranks right up.

I have a switch on my pump, but I leave it on continuously.

I seriously considering just bypassing the engine fuel pump altogether, and running the fuel line up the firewall along the back of the engine and straight to carburetor, to reduce the heat.  If it weren't for the vacuum pump, I'd just block off the engine fuel pump opening and remove it.

sweltering in Texas
Phil Auldridge
Austin, TX
1940 60S as well as MGA, Stingray, '39 Ford Coupe, BMW 3.0 CS, '59 Jaguar, '51 Hudson Hornet, '64 and '70 Mercedes roadsters, and Nash-Healey LeMans Coupe
[img]http://www.auldridge.org/images/hdricon.jpg[/img]

48ragtop

Thanks to all for the many excellent suggestions.

Paul:

I'm likely going to go with an electric fuel pump.  I had hoped to avoid this but it seems from many sources that this is the most dependable and in some ways simplest solution.   I'll probably install it in conjunction with the mechanical pump and provide a switch.   However it seems like it may be best to just run it continuously.   Do you have any problems with the electric pump trying to push through the mechanical pump?   Also have you run a secondary recirculating line back to the tank/electric pump?  Some recommendations I've seen suggest this as a way to keep the fuel coming in cooler and/or to mitigate fuel volume being pushed up front by the electric pump.   

Thanks again,  Ed
Edward M. Wisniewski, CLC #26482
1948 Cadillac Series 62 Convertible
1957 Chevy Belair Convertible
1982 AMC Eagle SX/4
2007 Chrysler Crossfire

Jeff Maltby 4194

Ed. You use to own a 49 Coupe De Ville correct ?
Jeffo 49er chapter

CLC 1985
Honda Gold Wing GL1500

Philippe M. Ruel

Quote from: 48ragtop on August 15, 2011, 04:15:19 PMa secondary recirculating line back to the tank/electric pump?  Some recommendations I've seen suggest this as a way to keep the fuel coming in cooler
This is exactly what GM engineers did in the 60s on many A/C equipped models (under supposedly hotter climates, and definitely more crowded engine compartments) : [mechanical] fuel pumps were 3-way on these models (2-way on others) by adding a return port and line.
1952 60 Special in France.

48ragtop

Jeff:

You must have me confused with someone else.  My 48 is the first Cadillac I've ever owned.   I'm sure that there is another Ed Wisniewski out there - possibly with a 49.   Common name in the "old country".

Philippe:
Engineers must have been on to something with the recir line.  Might be worth a try.  I'm still investigating and might give it a try.

Thanks to all.

Ed Wisniewski
Edward M. Wisniewski, CLC #26482
1948 Cadillac Series 62 Convertible
1957 Chevy Belair Convertible
1982 AMC Eagle SX/4
2007 Chrysler Crossfire

buicksplus

I had the best luck with my 40 LaSalle bypassing the mechanical fuel pump entirely and continuously running a rotary electric pump at the tank.  I leave the mechanical pump in place, just connect the input to the output with a short section of hose. This keeps the vacuum pump in place and operable.  That mechanical pump is like a boiler, it gets very hot and the fuel in it will boil before it gets into the carb. 

I run the fuel line from the electric pump to the carburetor, keeping as much distance as I can from the exhaust manifolds.

On a hot start, my engine will stumble and run rough until enough fuel gets in the carb to cool it off.  This usually takes a mile or two of driving.  After that, she runs great.

Good  luck, this is a common problem with old engines and modern fuel (ethanol).  I have usually been able to get most of my old cars to deal with it, it takes some trial and error to solve the problem.

Bill.

Bill Sullivan CLC# 12700

Tom Magdaleno

I like Bill's idea.  Although you can push through the mechanical pump, if you get a leak in the rubber diaphram you will pump gas right into your crankcase.  I run electric pumps with switches on all my cars just to help with cold starts, but it may be beneficial for you to run just an electric.  It would be easier than running a return line, which would be my next step.
Tom
'38 Cadillac V16
'71 Buick Riviera
'65 Chevy Truck
'56 Packard Super Clipper

pauldridge

Ed,

I'm using an AIRTEX E8016S pump (that's a 12V .. their 6V model is E8011).  I purchased mine from RockAuto.com for only about $37.  I chose this pump because of its low pressure.. 2.5 - 4.5 PSI.  My car DOES have one of those old-style pressure regulators at the carb (the one with a little oblong glass filter bowl).

I've had good luck with this brand.. installed on 4 of my cars and they all function flawlessly.  I suspect if you will be running both mechanical and electric pumps you'd want a pressure regulator after the mechanical pump.

I've had absolutely no vapor lock issues since adding the electric pump, even hot starts after parking (and I DO mean hot.. 105-8 degrees!).

I DO have a Carter 6 volt pump that I recently removed from my car in good working order, in conjunction with my conversion to 12 volt system.  It's a noisy little bugger, you'd want to mount it with rubber isolation.  I'd be happy to pass it along to anyone with a 6 volt system for shipping costs, as I doubt I'll use it again.  Just email me if you're interested:

phil at auldridge.org

Phil Auldridge
Austin, TX
1940 60S as well as MGA, Stingray, '39 Ford Coupe, BMW 3.0 CS, '59 Jaguar, '51 Hudson Hornet, '64 and '70 Mercedes roadsters, and Nash-Healey LeMans Coupe
[img]http://www.auldridge.org/images/hdricon.jpg[/img]

48ragtop

Many great suggestions and ideas.   Thanks to all.

I'm thinking I will probably install an electric pump and just by-pass the mechanical pump leaving it in place.   I may reroute the fuel line to keep it further away from the manifolds.    I'm simply trying to make sure I have a reliable driver and I am willing to compromise on authenticity as needed. 

My concern is with the type of pump, pressure, need or not for a pressure regulator and actual pump installation and wiring.

Any suggestions welcome.

Thanks,  Ed
Edward M. Wisniewski, CLC #26482
1948 Cadillac Series 62 Convertible
1957 Chevy Belair Convertible
1982 AMC Eagle SX/4
2007 Chrysler Crossfire

robert G. smits

Ed, go to "Electric Fuel Pump Alternative View" in General Discussion for an in depth discussion on the subject.  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

buicksplus

Ed:

I use the Carter 6V pump, suggest you take up Phil's offer for his. These pumps are expensive retail.   I use mine w/o a regulator, just a filter on the intake side of the pump.  As Phil says they are very noisy if not mounted with rubber isolators.

I have not had very good luck with the cheaper "Autopulse" pumps that are easy to find and sold under various names.  The diaphrams on these seem to fail easily and they have a hard time pumping in hot weather.

The Airtex looks good, price is right, but I have no experience with them.

Good luck, keep on pumping!

Bill.
Bill Sullivan CLC# 12700