How Much Gas Should a 1927 Model T Use?

[BLB27]

I drove my 1927 coupe 12 miles and checked the gas using Lang's dip stick. It used 1 3/4 gallons or 7 mpg. This was on a paved road and no significant hills. This seems like a lot of gas. Should I be concerned?

I have about 40 miles on the engine.

[TXGOAT2]

Yes. That's far too much fuel. Under good conditions a Model T coupe in good running order ought to get 17 to near 20 MPG at about 30 MPH with few stops and starts.

Your engine will get better MPG once it has run for a few hundred miles.
Be sure you are using the spark and carb adjustments properly, and be sure that your brakes and transmission bands are not dragging.
A T coupe would need about 28 to 30 PSI in the tires.

Higher speeds and headwinds will reduce MPG, as will stop/start driving.

PS: A short drive and gauging with a stick may not give accurate results. Longer drives will give more reliable data.
On a fresh build, I'd want to double-check all adjustments. Keep an eye on the water and oil too. Don't overfill the crankcase, but be sure it at or above the lower cock. Use a light bodied oil, like 10W30.

[TWrenn]

Well, once again my post got bounced by the previous poster. Can't believe how often this happens! Ditto to what Pat said, but I'll chime in what I tried to say to begin with...rebuilt engine will be a bit tight causing more fuel use for a while, incorrect carb setting will definitely cause it. Lean it back just til it starts to slow engine RPM's down, then richen it just a smidge to smooth it out and try that for a while. Improved cars are also heavier than the earlier ones. My '26 Fordor guzzles at 18 mpg, where the '13 touring is a consistent 24 mpg. with top down, about 20-22 with top up depending on the wind.

[TXGOAT2]

I get "bumped" from time to time. NBD.

[Norman Kling]

I agree with the above. You might want to put lenses in your headlights! They will catch some air without them which would give you wind resistance. As the engine wears in, it will get better mileage.
Norm

[Distagon2]

"Be sure you are using the spark and carb adjustments properly, and be sure that your brakes and transmission bands are not dragging."

If you are somewhat new to Model T's, I would very much check to make sure something isn't too tight, as said above. Are your bands cinched too tight and maybe dragging, or emergency brake lining a little tight? 7 MPG is extremely low even for a newly rebuilt engine. Once the engine starts, where do you advance the spark lever?

[Oldav8tor]

I have a 1917 with a Z high compression head and regularly get 20 mpg. Ditto to what the others said.

[Craig Leach]

Hi Bruce,
I would not check fuel milage in that short of a distance, or worry much about it. pull the plugs & look at them if black & sutty mixture is to
rich. By the # of post you have made I suspect you are not too new at this. I run 32-34 psi in my 21" tires. With the brake lever strait up you
can push the car the bands are brobably not to tight. The only time I'm cocerned about wind resistance on my model T is when it's on the trailer
@ 70 mph. Nice looking car! At a gas station in San Jose a motorist asked what kind of milage model T's got ( gas was close to $7 a Gal. at the
time ) Before I had a chance to answer the guy filling his T at the other pump said "Doesn't matter when you are having this much fun" .
Craig.

[Jerry VanOoteghem]

Is your rear end still running hot? Tightness there will rob gas mileage.

Also, not so obvious, can be extreme front end toe-in adjustment. Years ago, a guy in local chapter misinterpreted the toe-in specs and had way too much. The car seemed to have no power. I noticed his front tires were wearing really fast and asked about toe-in. Long story short, he adjusted it properly and said that the car flies along like it has an extra cylinder. He never mentioned gas mileage, buy I bet it was terrible, So, what's your toe-in set to?

[CudaMan]

I get 15+ mpg out of my 1924 with a Kingston L4 carburetor, not known to be the most efficient carb for a T. One advantage of the Kingston is that it's pretty much "set and forget" on the mixture, no fiddling required.

[TWrenn]

I get 15+ mpg out of my 1924 with a Kingston L4 carburetor, not known to be the most efficient carb for a T. One advantage of the Kingston is that it's pretty much "set and forget" on the mixture, no fiddling required.

Mark you should be able to get better than 15, even 15+ MPG, depending on what the "+" means. I assume tho you have the top up? Without a roll-up rear window panel, it's like dragging a parachute for sure. Being a cut-off it should be a bit lighter than a regular touring I would think. Like I said, Clara, my '13 with the NH consistently gets between 22-24 with the top down, one or two people, "typical" level driving. Add a few steep hills and a strong head wind and of course it drops to around 21. But still gets decent mileage even at that. I typically run her between 28-30 MPH.

[John Codman]

How did you check the fuel mileage? I don't see any evidence of a speedometer cable on the OP T. I have never attempted to check my 27's gas mileage, but it is sure better then that. A lot better. As has been said here, a new, tight engine will use a bit more fuel then a well broken-in engine, but only a bit. If it is really using that much fuel, you should see black smoke coming out of the exhaust. To use that much fuel, the engine would have to be waayy rich.

[TWrenn]

John when I go on tour I fill my tank to 9 gal.
My '13 has a very accurate speedometer plus I've also "backed it up" with my phone speedometer. After I'm back I stuck the tank and then do the math.

[Susanne]

I used to get a consistant 20+ out of Angel ('15 touring) but there was a caevat - it ran a Winfield V. In fact, about half of our family cars (including mine, the 15 and 19 roadsters0, had Ed Winfield's miracle machines of one sort or the other bolted to the intake... I certainly fell in love with them (once I learned how to dial them in), not as simple as an NH but that progressive jet tube actually worked.

The ONLY downside was the barrel throttle, because once the pivot point on the body started to wear, and because of the age of the carbs that wear was difficult to stop, it would leak vacuum... I figured out how to rebush it, which helped a LOT. You have to be careful, as a lot of them (especially the later ones) were pot metal, not aluminum... but it can be done.

Would I run another? You can bet your Bippy (OK, Banana company) stock on it - I'm currently between T's, but I just bought a 4V for a future car as yet to be determined....

[WatchDog]

Lenses in the headlights to improve mpg?? Now I’ve heard it all.

[jab35]

WatchDog:
No, the lenses will definitely improve gas milage, but they have to be those old purple colored glass to do any good! Possibly another factor in perceived poor gas milage is the hydraulic disc braking system, a little extra drag on all 4 wheels, and YMMV. jb

[Susanne]

... the lenses have to be those old purple colored glass to do any good...

True!! It has to do with refraction VS the speed of light, also the purple in the lenses are resonant to any nearby black holes, so there's a gravitational derivative involved... You have to be careful, however, as TOO MUCH purple can shift you in time, so you end up driving a car that was made in the last century...

You have to be even more careful with an earlier car, as if the sidelamps are also purple, you will start attracting strange beings in unusual clothing demanding information from you... or relating how their grandfather had one just like it...

- - - - - -

Back to seriousness...

There actually (and honestly) are a lot of factors that affect gas mileage, from how new the engine is (they take a lot of power just to run when new) to having the timing set right to good VS weak or mis-set coils to compression issues or vacuum leaks to even, yes, carburetion... but I would expect, all things being equal, to get thereabouts 20 to the gallon. If your motor is spanking-new, it's going to be tight, things are still wearing in and bedding in, so yeah, your mileage will certainly suffer for the first few hundred miles... once things get bedded and loosenes and sealed, your mileage (and performance) will improve.

[John Codman]

John when I go on tour I fill my tank to 9 gal.
My '13 has a very accurate speedometer plus I've also "backed it up" with my phone speedometer. After I'm back I stuck the tank and then do the math.

...and that is the way to do it. My point was that I don't see any evidence of a speedometer cable in the original post. I simply have a problem believing that a stock Model T can use that much gasoline without some obvious sign of trouble. It has to be leaking or it is running extremely rich.
I also don't believe that installing the headlights will have a significant affect on gas mileage. If the car was cruising at 60 MPH yes, but at Model T speeds, the wind resistance would be slight. All other factors remaining constant, drag increases at half the velocity squared.

[jab35]

Susanne: Thanks for chiming in, and for giving serious commentary.

[WatchDog]

WatchDog:
No, the lenses will definitely improve gas milage, but they have to be those old purple colored glass to do any good! Possibly another factor in perceived poor gas milage is the hydraulic disc braking system, a little extra drag on all 4 wheels, and YMMV. jb

Love it.

[Oldav8tor]

I have hydraulic rear disc brakes - still get 20 mpg.

[TWrenn]

John when I go on tour I fill my tank to 9 gal.
My '13 has a very accurate speedometer plus I've also "backed it up" with my phone speedometer. After I'm back I stuck the tank and then do the math.

...and that is the way to do it. My point was that I don't see any evidence of a speedometer cable in the original post. I simply have a problem believing that a stock Model T can use that much gasoline without some obvious sign of trouble. It has to be leaking or it is running extremely rich.
I also don't believe that installing the headlights will have a significant affect on gas mileage. If the car was cruising at 60 MPH yes, but at Model T speeds, the wind resistance would be slight. All other factors remaining constant, drag increases at half the velocity squared.

Yeh after I re-read your post John I realized what you were getting at. Sometimes my brain just ain't in gear! Ha ha.

[Susanne]

Susanne: Thanks for chiming in, and for giving serious commentary.

Hopefully you are still reading, would you mind sending me a private e-mail jab35(at)cornell(dot)edu
I read in an old post that you were considering making Hyatt style spiral roller bearings. Did that project get any traction? And if you don't mind sharing the successes and sorrows that might have taken place. Thanks so much. And to the rest of forum, I'll remove this once I hear from Susanne, or some days after I don't hear from her. Thanks, jb

Sorry to report I haven't had any luck with the project here... I originally was going to look into setting up the machinery to do it myself, but ran into issues with both space and regulatory issues here in Italy producing these as a one off (or several-off) which would make producing them either cost prohibitive or impossible...

[jab35]

Sorry for more OT.

Susanne, does the machinery to form the rollers still exist or does that need to be re-invented? Thanks, jb

[Art M]

The machinery to wind the Hyatt type bearings would not have to be reinvented, just either find the old winder or make a new one. No one seems to know what happened to the Hyatt machine when we stopped making wound roller bearings as well as many other type bearings in 1989. The bigger problem im would be the heat treating.

I am wondering why there is a concern about the need to make these bearings.

Art Mirtes

[TRDxB2]

I drove my 1927 coupe 12 miles and checked the gas using Lang's dip stick. It used 1 3/4 gallons or 7 mpg. This was on a paved road and no significant hills. This seems like a lot of gas. Should I be concerned?

I have about 40 miles on the engine.

I was looking at your "My 1927 Model T Coupe Restoration" viewtopic.php?f=2&t=20699
and didn't see a speedometer/odometer just a hole cut in the dash. All the things you did look on the up-n-up, so I was wondering how you calculated the distance traveled & how you measured the fuel in the tank (before and after the trip). The stick on the hump indent at the bottom of the tank could cause an error in reading. Wouldn't take much with just 40 miles of driving

27 tank.jpg (28.14 KiB) Viewed 3268 times

[TXGOAT2]

The car must be standing on level ground for accurate measurements.
The farther the car is driven between measurements, the more accurate the measurements can be expected to be. It's normal for MPG to vary due to about 1,000 variables that affect it.

[Norman Kling]

I haven't seen anything about the ignition system. If you are using the original magneto and timer with coils, and everything is in tune it will get the best mileage. Likewise the float level and adjustments of the carburetor should be correct and all the passages in the carburetor clean.
I will tell you of a personal experience I had. My magneto went out right after I installed the rebuilt engine. I switched to battery and ran it on 6 volt battery with the coils and timer for about 10 years. It was one of the slowest cars on the tours and used a lot of gas. Then When I rewound a few magneto coils I decided to work on the magneto and fixed the magneto. That was the only thing I did and from then on I used magneto. Everything else was the same. I now had one of the faster cars and got much better mileage. With timing set properly, it will run best on magneto.
The best way to check mileage is to take a route where you know the distance accurately. There should be a gas station at each end of the route. Fill up all the way when you start. Drive the full distance 50 miles or more. Fill up again. Then take the fuel measurement from the gas pump and divide by the number of miles. Anything else is guesswork. It also makes a difference if you are going uphill or downhill or relatively level ground.
Norm

[TXGOAT2]

Ford recommended running on magneto for best performance. My experience is consistent with that. My car runs much better on magneto.
But with a "new" car, I'd want to check everything, especially things like band and brake adjustment, and make certain that carburetor and ignition settings are within bounds. Also, watch oil and water levels carefully.