Fuel delivery problem on depot hack

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Model T Ford Forum: Forum 2012: Fuel delivery problem on depot hack
Top of pagePrevious messageNext messageBottom of page Link to this message  By HARRY A DAW on Monday, July 23, 2012 - 11:12 pm:

Need ideas, suggestions. I have a 1923 with a hand built depot hack body and the gas tank is just in front of the rear axle under the bed. Carb is a nh that was on another T and really ran good on that T. Engine has B crank, dual exhaust, high volume intake manifold, and stripe cam (sorry to the purists, Dad built it for car tours. The passenger seat is even on a wench that could lower my mother down to the same highth as her wheel chair). I currently have a tractor type sediment glass bulb out of the tank running into a 5lb fuel pump with a regulator attached. Problem: I cannot get and keep the mixture right on the carb. After I get it running decent it will either start bucking or flood out. I need someone riding with me to constantly adjust the carb. Going up hill or down hill will also mess with the settings. Does the fuel pump need to be at the tank or could I put it close to the carb? Will it suck the gas from the tank or must it "push" it? Some of you have had similar problems with the tank below the carb. What did you do to solve the problem? Currently I think I have the regulator set on 3 lbs but have tried various settings.


Top of pagePrevious messageNext messageBottom of page Link to this message  By mike_black on Tuesday, July 24, 2012 - 12:24 am:

Both of my speedsters have tanks on top of the frame behind the seats and downdraft carbs. One has the fuel pump on the firewall and the other has it mounted where the generator used to be. I've never had that problem. I turn on my fuel pump and I can hear it pump until it builds up pressure then the clicking stops. That's when I start it.


Top of pagePrevious messageNext messageBottom of page Link to this message  By mike_black on Tuesday, July 24, 2012 - 12:30 am:

Harry, I re-read your post and you said the carb worked good on another car, it reminded me of something. I bought an elec fuel pump last year to pump some bad gas out of a boat. I can hold my thumb over the outlet hose of that pump and it never stops clicking--it just keeps building up pressure until it squirts out somewhere!


Top of pagePrevious messageNext messageBottom of page Link to this message  By Steve Jelf, Parkerfield KS on Tuesday, July 24, 2012 - 12:53 am:

A lot of vehicles have the fuel pump in front near the carb. That shouldn't be a problem. I think the problem would be if the pump overpowers the float valve. Are you sure the regulator is working?


Top of pagePrevious messageNext messageBottom of page Link to this message  By HARRY A DAW on Tuesday, July 24, 2012 - 08:22 am:

Mike, it never goes into the clicking. It continues to pump. I thought it might have a bypass allowing it to pump continuously. Maybe that is the problem. Thanks for your input. Yes I have tried the regulator from 1/2lb to wide open. It either starves the engine or floods it.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bill in Adelaida Calif on Tuesday, July 24, 2012 - 10:12 am:

The root problem may be twofold. 1. there are a lot of low quality fuel pumps out there. 2. most cheap pressure regulators control the pressure of a moving liquid or gas but allow the pressure to climb a bit if static.
The best (and period correct) way to solve the issue might be a vacuum tank mounted on the firewall.
Just my 2 pennies

Bill


Top of pagePrevious messageNext messageBottom of page Link to this message  By HARRY A DAW on Tuesday, July 24, 2012 - 12:37 pm:

Bill your thoughts about a vacuum tank mounted on the firewall have been my thoughts also. I have only seen pictures and read about them. If anyone knows of a source, please pass it on.


Top of pagePrevious messageNext messageBottom of page Link to this message  By mahlon hawker on Tuesday, July 24, 2012 - 04:34 pm:

I have several hit and miss stationary engines that have plunger fuel pumps drawing the fuel from the gas tank in the engine base and pumping it direct to the carb. The carb has a fuel bowl but no float. There is a standpipe in the bowl that returns excess fuel back to the tank, therefore the fuel level remains constant.

Using this principle and since you already have an under-frame tank and electric pump, why don't you try this...

Add a metal 1 qt. tank on your firewall. Run a 1/4" fuel line from the pump to the top of the tank. At about the 3/4 full point add a standpipe running out the bottom to a 3/8" return line back to the fuel tank. Plumb the normal fuel line from the tank bottom down to the carb. This way you have a constant head of fuel at a constant pressure for the float. Set your regulator pressure so just enough fuel goes to the header tank without overwhelming the return line at idle.

Tony


Top of pagePrevious messageNext messageBottom of page Link to this message  By HARRY A DAW on Tuesday, July 24, 2012 - 05:29 pm:

Found a drawing of a Stewart-Wagner fire wall mounted vacuum operated tank. The drawing is extremely small but I can see that it is a rather complex set up with a float and flapper valves. Probably not possible to find a real one in decent shape so probably a new fuel pump maybe mounted near the carb will be in order unless some other ideas come along. Tony I will give your idea some thought as well.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Royce in Dallas TX on Tuesday, July 24, 2012 - 06:07 pm:

It might be cheaper and easier to just mount a Model T gas tank under the front seat and do away with the fuel pump. I don't have any fuel pumps on any of my Model T's. Never had a fuel pump failure yet.


Top of pagePrevious messageNext messageBottom of page Link to this message  By HARRY A DAW on Tuesday, July 24, 2012 - 09:52 pm:

Would if I could Royce. Under the drivers seat is a wench which is connected to the passenger seat. There is a false door on the passenger side which opens and a track can be lowered. The wench will then lower the seat down that track and back up for a handicapped person. Might consider mounting a speedster type tank behind those seats though. I spent 4 1/2 months in the hospital and nursing home rehab center last year fighting a MRSA staff infection from a knee repair surgery. If the infection does not come back I get the knee replaced December 4th. I hope I will not need that handicap accessory but kind of glad it is there in case this surgery goes bad like the first one.


Top of pagePrevious messageNext messageBottom of page Link to this message  By HARRY A DAW on Tuesday, July 24, 2012 - 09:55 pm:

Picture of vehicle.Depot Hack


Top of pagePrevious messageNext messageBottom of page Link to this message  By Allan Richard Bennett on Wednesday, July 25, 2012 - 06:36 am:

Harry, my 1924 Tourer has a colonial body built in Adelaide. To lower the body lines, the standard fuel tank was shifted from under the front seat to hang under the spare wheel carrier at the rear. To get fuel to the standard NH carburetor a Stewart Warner Vacuum tank is bolted to the firewall. The only problem I have ever had was when I forgot to turn off the tap on the bottom and a slow leak drained the little tank. It just needed re-priming through the little plug in the top.

These are period fittings on a lot of old cars. Mine is the same as that fitted to Dodge cars of the 20s so you should be able to source one relatively easily.

Hope this helps.

Allan from down under.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Royce in Dallas TX on Wednesday, July 25, 2012 - 06:47 am:

There is someone who rebuilds those firewall mounted vacuum tanks, I've seen them at a swap meet somewhere. They basically use vacuum to run the pump that pulls fuel in the tank, which gravity feeds the carburetor.

Might find one here:

http://www.hemmings.com


Top of pagePrevious messageNext messageBottom of page Link to this message  By mike_black on Wednesday, July 25, 2012 - 11:24 am:

Harry,
Seems easier to put the tank in the floor and build a back seat around it!


Top of pagePrevious messageNext messageBottom of page Link to this message  By mike conrad on Wednesday, July 25, 2012 - 02:12 pm:

Harry, Nice car. I like the idea of a vacuum tank. I have one on my 1920 dodge brothers touring. They won't over pressurize your carb. and are ideal for cars that uses gravity flow carbs like ford's NH I have found them to be plentiful and reliable. 90% of all problems people seem to have with these tanks involes vacuum leaks between the two easily remade main gaskets. If you do go down this road try to find one that is at least rebuildable. Look carefully at the potmetal top as they can crack from over tighting the fittings or screws. Also remember stewert warner tanks were used on many different cars in the 20's so they are not too rare.


Top of pagePrevious messageNext messageBottom of page Link to this message  By HARRY A DAW on Wednesday, July 25, 2012 - 05:46 pm:

The back seat is a thought. I never haul anything in it. I too like the idea of a vacuum tank but have no idea where to begin looking for one. I have Googled them and found that at least most were made by Stewart-Wagner but that is as far as I have gotten so far. This may have to go on the back burner till after I can recover after knee surgery in December but I really appreciate all the input and ideas. I was just sure that someone was running a fuel pump and regulator and tell me where I am going wrong. My cousin said one pound pressure will raise water 17". I know it might idle with one pound on the regulator but it starts bucking bad and hardly runs above idle. He thinks there may be crud in the tank. If I catch a day when the knee will stand it I will take the line off the carb and put a 5 gallon container under it and watch the flow.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Brian Sullivan, Powell WY on Thursday, July 26, 2012 - 10:22 am:

Pulled one off the shelf so you can see what the gadget looks like.

PM me if you want to see more photos of the internals, or if you want a pdf of the installation manual. Note the size relative to the transmission cover.




Top of pagePrevious messageNext messageBottom of page Link to this message  By HARRY A DAW on Thursday, July 26, 2012 - 01:51 pm:

Thanks for the pictures Brian. Now I know what one looks like and what to look for.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Gary H. White - Sheridan, MI on Thursday, July 26, 2012 - 05:43 pm:

New kits available for vacuum pumps.
http://www.classicpreservation.com/vactankkits.html


Top of pagePrevious messageNext messageBottom of page Link to this message  By Gary H. White - Sheridan, MI on Thursday, July 26, 2012 - 05:54 pm:

There is another method of pressurizing your fuel tank by tapping the exhaust pipe and running a tube to your fuel cap. Very safe I understand. To be sure a fuel filter can be added to work as a flame suppressor. Pg 77, Tinkering Tips Vol I. About 1 lb pressure in tank is created.


Top of pagePrevious messageNext messageBottom of page Link to this message  By HARRY A DAW on Friday, July 27, 2012 - 01:07 pm:

Thank you Gary for the webb site. I have it saved. Now I need to find a tank.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Gary H. White - Sheridan, MI on Friday, July 27, 2012 - 03:15 pm:

A couple on ebay right now. Make sure to ask if insides are OK, not rusted or missing.
Gary


Top of pagePrevious messageNext messageBottom of page Link to this message  By Gary H. White - Sheridan, MI on Friday, July 27, 2012 - 03:16 pm:

A couple on ebay right now. Make sure to ask if insides are OK, not rusted or missing.
Garyhttp://www.ebay.com/itm/VINTAGE-1920S-VACUUM-FUEL-PUMP-/180938759950?hash=item2a 20ca5f0e&item=180938759950&pt=Vintage_Car_Truck_Parts_Accessories&vxp=mtr


Top of pagePrevious messageNext messageBottom of page Link to this message  By HARRY A DAW on Friday, July 27, 2012 - 08:06 pm:

Thanks for the information Gary. I am also playing with dimensions of an under seat gas tank that I could put behind the passenger seat.
This upcoming knee surgery may keep me from doing anything in the very near future.


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