Am I Nuts?

Lars99@aol.com

Lars99@aol.com

Senior Member
I want to redo my original red fluid fuel gage in my 32 roadster. Trying to keep things close to fifties build, (I know we had electric fuel gages then). Any experience or tips on rebuilding this would be appreciated.

Also running 3/16" return line from double outlet fuel filter (after mechanical fuel pump.) Installing an electric fuel pump near tank. Have had some vapor lock problems. Any suggestions here?

Final question. Running six volts. Where can I buy a six volt sending unit with six volt gas gage, if I decide to abandon the original gage?
 
I reinstalled my original hydrostatic fuel gauge about 3 weeks ago for my 34. I took it all apart. The steel enclosure for the gauge was a little rusty near the top of the glass tube, so I soaked it rust 911 for a week and then thoroughly cleaned and dried it and then painted it with rustoleum. I cleaned the glass tube with a Q Tip with most of the cotton pulled off. I also painted the little piece of cardboard that was inside the gauge white, as it was pretty yellowed from age and also stained with red liquid. I used red gauge fluid from classic and exotic. Some people on the barn said to put the red liquid up to the lowest level on the gauge. I used a syringe to put the liquid in after I installed the gauge. This allowed me to remove some liquid after I overfilled it by accident - hard to put the liquid in under the dash and see the level at the same time. I ended up with the level at about the 1/4 mark. I figured this was good as I have read that the liquid does evaporate over time. I cleaned up the end of copper tube good and soaked it in CLR overnight. I them attached the copper tube to the gauge using Teflon tape on the threads. So far I have driven the car three times. The first two were on rough roads, as the instructions I had said to aid that gas sloshing in the tank created bubbles and formed the pressure in the tube. The level did go up while I was doing this - up to between the 3/8 and 1/2 mark. I was expecting that the gauge level would always stay at the same level even when the car was not driven, as it is hydrostatic. However, the level went to zero as the car sat for a week. However, when I drove it, it went back up. I don't know if this is normal or if I have a slight pressure leak. I expect I have a leak. I tried retightening the fitting of the copper tube. After that I filled the tank, and the level did go up to about 3/4. I have driven the car once after that and let it sit for about a week and a half. It is currently reading at about 1/4, so retightening the fitting on top helped the gauge not go to zero. So I am still in the experimentation phase. At a minimum, I have some indication of fuel in the tank. Whether I can get it to read at F when full and E when empty is still to be determined. Maybe I need to add more fluid in the gauge - I'm going to try driving for a few tank fulls and see what happens. It never did go to F when the tank was full - only 3/4. The color of the red liquid with a clean tube and a white cardboard background is very distinct - looks good.
 
Jim
Thank you for your honest explanation of your progress. I have all the parts, except for one item on back order, but am still on the fence vs going electric. Mine is a rod, (already did the Dearborn thing a couple of years ago), so, I have that much room. But I am a traditionalist and would like to keep this, about 70% original 32, original.

Any vapor lock problems?
 
I don't have any vapor lock issues. I assume you have an original gas tank with the fuel pickup unit in it and the little copper tube that runs to the gauge. You need this to be functional to make to hydrostatic gauge work. I am using an electric fuel pump rather than the original mechanical one but gas tank, fuel pickup and copper tube are all still functional.
 
The old chemical they used for the red dye is unobtanium now but the stuff that is available now days works fine. It slowly turns back clear as the dye fades but it will last better if it stays out of the sunlight as much as possible.
 
JimG I have experienced the same problem. I consulted a gauge manufacturing person and told me to solder the connection where the the air tube meet the nut at the sending unit. I thought about it for awhile and being the the rumble seat and everything was put together at an area tough to get at with an iron. I decided to try epoxy and apply some around the tube on top of the nut. Seems to help solve the problem so far. I know removing the nut at a future time may be of a concern, I can always cut and put a new flaring and nut. The same goes for under the dash.
 
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As well as the sloshing in the tank you can remove the flex line at the fuel pump and blow back to the tank ,this creates bubbles at the tank pick up and gets the gauge working ,and if like sniff on it a bit and it will keep you happy all day ,LOL T ed
 
Alright. I can blow, taste and sniff. How about the return line? If I drill an extra hole into the tank pickup fixture for the return, I am thinking I will have to add a diverter to avoid dumping fuel onto one ot the two "trays" present in the original pickup. Otherwise, it might screw up the gage, right? This is getting complicated.

Has anyone tried this return line to keep the fuel cool and avoid vapor lock?
 
Vapor lock is an excessive heat build up in the fuel delivery line adjacent to hot spots on the engine and overheated carburetor bowl that can cause boiling of the fuel (vaporization). The line from the firewall to the tank should not be affected unless an exhaust system leak would be blowing hot gas on the line somewhere down under the car.

I don't understand what you mean by a return line. There is no need for anything other than the existing air line, the fuel supply line, and the vent tube that are all a part of the sender unit. This explanation at the Ford Garage site is a good one about how it all works. http://www.fordgarage.com/pages/32fuelgauge.htm

A return might be causing a pressure problem at the carburetor and should not be necessary.
 
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the only time you need a check valve and a by-pass is with a rotatory fuel pump like a carter pump ( i have a pdf i could look for on installment). A push pull type electric pump does not require a bypass, a pump such as an airtec. Its passive.

Pump related anyway. Gauge wise... I'll keep watching and reading as you share.
 
I know that some of the modern carbureted cars use a pump with a return for this purpose but it was not a real big issue with the old flatheads and there are other ways to deal with problem areas by insulating the hot spots with heat shields or insulator carb spacers. I remember folks would put clothes pins on a fuel line to act as an insulator and it actually worked to solve problems for the most part. Looked funky though. Some folks misdiagnosed other heat related problems as vapor lock only to find that they had a bad condenser. A lot of stuff was also made for emission controls starting in the late 60s & early 70s to control vapors from escaping into the atmosphere. We still have those systems on the modern cars.

A person can do what they want to no problem but I tend to be more minimal in that respect and try not to fix a problem that doesn't exist yet. I've never had a vapor lock problem with the stock 1951 Mercury cars. I never had a problem with my later 50s, 60s, & 70s cars either. There were some cars that I noticed had problems due to their design back in the carburetor era. The modern fuel injected cars should never have problems since the fuel lines are always under positive pressure and the lines are generally shielded when necessary.
 
I know, we had flatheads that took us all over the country and never a blip. I remember as a kid, when funds were low, I even ran diesel fuel in the 50 Merc and she ran, (poorly, but got us there). But the new fuels are more volatile at lower temps. And that means when you are at a stop sign or in traffic, the fuel heats up and vaporizes. That is why I am installing a return line, to keep the fuel as cool as possible. Also, insulating the carbs and keeping the fuel lines away from hot spots.
I hate being towed!
 
And I agree with rotowrench as I have a very stock 1950 Mercury Sport Sedan and over 30 years ago when I first purchased this car I was warned that the fuel pumps were poor and vapor locking was common. This was total BS and yes my car was constantly doing this with the necessity of carrying water in the trunk to limp a few more miles but one day it totally died a block from home and plop plop plop as our feet pounded the pavement pushing the Merc home and I changed the fuel pump with a new pump. Guess what?? The vapor lock was gone!! Bad pumps? 30 years ago I put a spare pump in my trunk and all these years of it rattling around still in it's new carton I have never needed it!!! The two spare items in my trunk? A fuel pump that I never ever needed and a new 6 volt headlight;) I will be changing the pump in the future with a dual diaphragm pump for the wipers but due to wives tales years ago I was told they were hard on the pushrod and camshaft and all these years I have had 3 NOS ones on my shelf so this will change. Most likely they are not hard on the cam and rod but if anything they are a balanced load instead. This was probably an excuse not to purchase because they were more expensive:rolleyes: I ended up with all of these pumps from an old local garage that went out of business and I used to purchase dead stock water pumps, fuel pumps etc. at the auctions. Some i don't know what they are for of course.
 
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