Moving gas tank rearward?

[signsup]

For various reasons, on my former depot hack now WWI ambulance project, I feel the need to move the gas tank a few inches towards the rear on the frame. More leg roomk more clearance under the steering wheel, etc. I'll need to drill another hole or three through my sub frame and through the top of the T frame, but that's all doable. Then, redo the fule line to the carb.
My question is . . . as long as I keep my height from the frame the same as original, are there any other issues that I need to be concerned about? Is adding a few inches to the lenght of the fuel line an issue? And, now that I write this, it just occured to me that the tank brackets were mounted on top of a 3/4" sub frame board and then to the T frame, so that would have actually raised the tank 3/4" than OE, which would not have helped fuel starvation issues. So I may think how to lower tthis tank to the original height as well as moving it back a few inches.

Thoughts? It is an oval tank.

[Oldav8tor]

What year is your T? If it was built around WWI I would think it originally had a round tank. My 1916-built 1917 Model year has a round tank under the driver's seat, bolted directly to the frame. That said, I would think you could move a tank back a couple of inches without issue. If you have a NH carburetor you might consider adding a Scott Conger Full Flow valve just to insure adequate fuel flow to the carb under lower fuel pressures.

[JohnM]

One thought, maybe not enough to matter, moving the tank back will essentially set it lower from the carb when going up hill.

[signsup]

Unfortunately, due to budget restraints, I am starting with a 26/27 donor depot hack that will be a T salad when complete, but all the ambulance wooden pieces are built from Ford plans for the 1917 T. So, my engine is a 26/27 along with a Holly G carb with the swivel top and choke rod and an oval tank with two straps, one a two bolt mount and one is a one bolt mount. One long hard gas line from tank glass bowl strainer to frame, then 45 degree bend along frame to carb, no shut off other than at strainer.
I may cut current har line at long straight run under seat and replace with rubber fuel line until I get everything finalized and if engine runs well, I can replace the entire line with one custome bent line.
Just gotta keep away from that exhaust pipe.

[Jerry VanOoteghem]

...the tank brackets were mounted on top of a 3/4" sub frame board and then to the T frame, so that would have actually raised the tank 3/4" than OE, which would not have helped fuel starvation issues. So I may think how to lower this tank to the original height as well as moving it back a few inches.

No. Raising the tank will HELP with fuel starvation issues.

Moving it back a few inches will have no ill effects.

One long hard gas line from tank glass bowl strainer to frame, then 45 degree bend along frame to carb, no shut off other than at strainer.

"Glass bowl strainer"? Bad idea to have a glass bowl under the car where stones can strike it & break it. "no shut off other than at strainer" is also bad practice. There should always be a shut-off at the carb, unless you plan to crawl under the car to shut off the gas after each use.

[signsup]

Appreciate the comments. While trying to get as much clearance under the steering wheel as possible, the thought of keeping the tank on the frame rail instead of the sub frame board seemed like a good idea. It could not negatively affect guel starvation any worse than OE, as that is what I would be putting it back as. But, the 3/4" height difference will not affect me as much asmoving the tank back 3 or 4". so I will probably leave it on the sub frame. And, unfortunaely, this is one of those cases where there is never enought time to do it right, but always enough time to do it over. I may just rubber fuel line until I get through the Memorial Day parades and then replace the fuel strainer, hard line and install a carb shut off and do it right. The parts are all there now, so I'm not wasting any funds, just some time down the road.

[Craig Leach]

Hi Robert,
One of the great things about a build over a restoration is the ability to take artistic liberties ( within reason ) when it comes to comfort &
drivability. Anyone without a tape measure in hand will not notice a couple of inches back and down with the seat but you most definitely
will when it comes to comfort & ease of entry. When I built my fire truck instead of shortening the drive shaft for a Muncie I lengthened
the frame 13 1/4 " then used the extra length to make the seating & hose bed more comfortable. You can easily enter from the left side with
the hand brake pulled back. As far as gas flow, if you are using a oval tank you can raise it up some to give a better gravity feed & clearance
with out raising the seat or even lower the seat for more room. It sounds like the ambulance will be rather heavy so you may want to consider
a 10 tooth pinion it really helped on the fire truck.
Craig.

[signsup]

Thank you for the encouragement. I am 5ft 16in tall and 220lbs, so every inch I can get, I'll take. But my wife is a foot shorter and the steering wheel was hitting her legs and the wheel was in her gut, so she is the one that was looking for some relief and I'll do what I can to make that happen. I do not drive anyways, so it is her comfort that is my primary concern. And, she probably resembles the average height of a WWI ambulance driver than I do, so it will be proportioned.
I'm not planning on carrying wounded, so I will wait and see what the power is like after completion. The bed is much longer than a T and there are two fold down jump seats for 4 wounded soldiers to sit on with no stretchers and they are mounted as far forward as they can be in the rear bed to keep as much weight as far forward as possible.
I have it on jackstands right now and climbing in the rear is a creaky, hope the whole thing does tip backward kind of adventure. But, so far, so good.

[Humblej]

Perhaps your problem is not the gas tank but the steering column.

[signsup]

Here is what all the fuss is about. I'd like to move the tank all the way back to the division panel without touching. Maybe 2 inches, but we'll see what the net affect is on the bench seat.
Also pic of those bench seats showing how far forward they want the weight in the rear. Two stretchers on floor would bump the handles up against the division panel with hole cut in the tail gate for the rear handles to stick out.

[Allan]

Raising the fuel tank and moving it forward both help with fuel supply. Think of the improved 1926-7 cars with the fuel tank in the cowl. The lower you go and the further back you go, the worse it gets. My Duncan and Fraser roadster has the tank in the turtlledeck behind the seat back. This backward step is compensated for by mounting the tank approx. 5" higher than standard.

Allan from down under.

[Oldav8tor]

Later cars were a bit of a tighter fit. Since this is supposed to be a WWI ambulance, you might want to go with an earlier style steering wheel. They were smaller in diameter, 15 (14.59) inches compared to 17 inches in a 1926. It would also be wood painted black (or maybe OD), not Fordite. I believe the spider is a little flatter in the 26 which would put the wheel back even farther.

[Norman Kling]

Any other gas filter other than the original type sediment bulb with screen is too much for the gas to get to the carburetor. The fuel shutoff should also be at the tank. The sediment bulb has the shutoff valve. You can get good reproductions of the sediment bulb from the suppliers. You can also mount a shut off at the carburetor to shut when parked just in case of carburetor leaks and to be easier than to crawl under the car. Also the lowest point in the line should be between the carburetor and the bulb. It should go up at each end so that any air bubbles will rise to either end and not be trapped between causing "vapor lock". Some people have installed an electric fuel pump in the line to keep the flow to the carburetor, but this can cause too much to get into the float. Best to just leave it as Henry made it and keep the tank over half full if you expect to climb any hills.
Norm

[signsup]

Here is what it looks like after the approx. 3" relocation. I've left it on the sub frame, so it is still 3/4" higher than Henry had it. Took off my glass bowl fuel strainer and noticed that bubba had welded on a larger threaded nipple to the tank so that the standard potato will not fit unless I screw on a bunch of adapters and that lowers the fuel line connection. So, I'll leave it as it has a screen filament in it as well as a shut off and fo from there.
I've got several steering wheels in stock, so I will look at a smaller wheel or a more depressed spider to get the wheel out of her gut.. And, I checked to make sure my steering column mounting flange was on the hood side of the firewall.
Talk about tight, we made the rear box to Ford specification and it is 48" wide and 48" tall. It is like a dog house in there.

[kmatt2]

My 1916 wood body open express pick up has a stock round gas tank moved back a little less than one inch and all is ok. The car has a stock 1916 wood fire wall mounted in the stock location. Behind the stock fire wall is a 3/4 inch wood fire wall cut out for the steering gear and coil box mounting to stock fire wall. The round gas tank is mounted to the frame with stock gas tank brackets to keep the top of the gas tank below the seat bottom and the express body has a 3/4 inch wood box platform for the seat. The carburetor is a L2 Kingston on a stock T intake. From your pictures I see that you are using an oval gas tank. In 1921 Ford lowered the touring front seat, but the roadster seat didn’t change. Ford used the oval gas tank to clear the lower touring seat, for your 1917 type body you could rase the oval gas tank up some for better gas flow to carburetor. As with any pre 1926 T it is best to keep the gas tank filled if driving up very steep hills.

[signsup]

While piddling with the revised seat frame today, I noticed that the tank straps are actually drilled through a 2x6 board laid flat as part of the sub frame for the former depot hack. Then through the original holes on the frame. I can pick up this board as it overhangs the inside top of the frame and move the straps in a little and mount to the board and not have to drill new holes in a stock T frame. I have just enough wiggle room to allow the tank lid to unscrew without interference from a strap.
After moving everything back 3" I now have a 3" gap in the floorboards to where the depot hack had a cross member rabbited for the large flat floorboard with the starter switch hole and hand brake notch. So I need to fill that gap with lumber and all should be good when painted OD green or stained dark walnut as I plan to do on the floorboards to hide wear and tear.
Cut the new seat bottom boards, I am making two seperate seats so that only one section needs to come out for filling the tank, which it seems I will need to keep topped off.
The reversing up a hill to avoid fuel starvation is one of the more grin inducing car show story.

TO THE WORKSHOP!

[signsup]

So the point of the last post was that my tank is sitting 1 3/4" on top of the stock rail, so fuel starvation should not be an issue as much as a stock pre 26 T. Probably part of the reason why we had a steering wheel clearance issue. My new seats will clear the tank by about 1/2" and the forward seat riser is literally touching the tank straps. It is held in place with four screws into screw blocks.

[Mark Nunn]

I am being selfish here, Robert, when I say that I would really like to see more photos of the progress on the ambulance. It sounds like a fun project and I would like to peek over your shoulder and see what you're doing.

[Jerry VanOoteghem]

You seem concerned a lot with fuel starvation. With a proper* fuel system, most of the time, depending on where you drive, it's not an issue. It is however a topic that a lot of people like to discuss. In your case, the limiting factor in steep hill climbing may likely be the weight of the ambulance.

*Meaning "stock Ford"

[signsup]

My driving with this project will be limited to parade routes and parking lots and high school activity fields, so I'm not overly concerned about fuel starvation, but the topic is often discussed and I was just checking to be sure that my tank movement did not incur other issues that I was not familiar with such as vapor lock, fuel starvation, lowering the fuel input rate by increasing the run, changing the center of gravity, etc.
Appears that I will not. And, yes, I have not run this ambulance yet on the road, so the weight will probably put it in the TT range of performance. But, for my purpose, that is OK.
According to my research, the Ford 1917 ambulance did not have any modification to the running gear, so it was a stock chassis with the ambulance body attached.

[Norman Kling]

I think some sedans actually had the tank under the back seat, so if the fuel level is kept up in the tank probably no problem. There is at least one thing I have experienced on one of my cars. I would always have fuel starvation on hills even with a full tank. I had bought a rebuilt carburetor, a Holly NH. The fuel input valve into the carburetor was a Gros Jet. That jet looks like a ball bearing which is operated by the float. I replaced with a needle and seat and no more problems.
Norm