MTFCA Forum

I recently rebuilt my 1918 motor. I replaced the cast iron pistons with aluminum, high compression head, up graded to hotter cam, large intake valves, and have a distributor. I also changed the gearing.

Before the up grade I was able to achieve 21-22 miles per gallon. Now the mileage dropped to 20-18 miles to a gallon. I can't find any fuel leaks. Any suggestions.

Gnitseretni eb dluohs siht.
4/20/21

Lead foot. now that you can, you do.

More HP more fuel.

Is this April 1?

Larger valves allow more gas into combustion chamber. And you misspelled s_ _t

Your rebuilt engine is probably tight, and the rings may not be fully seated. A hotter cam generally is not conducive to better fuel economy. Raising compression usually is. You may need to change your driving style to get the best economy from your new, altered engine. Spark advance settings and carburetor settings may need to be adjusted differently than before. Your engine as altered will probably perform better at somewhat higher RPM/road speed than it did previously. I'd run it for 20-30 hours at various speeds and loads before I started worrying about fuel economy. Once it's run-in, it may give better mileage running at a slightly higher speed than its previous "sweet spot".

?thgir ,niahc ruoy gnillup si eh taht ezilaer uoY

.ton sseug I

.htn1 eht ton ht02, eht s'tI

What am I doing wrong? I've seen others on the forum claim 20-25 MPG. I have had 7 T's from 1912, 1915, 1916, 1920, (2) 1924, and 1925. I have never gotten better than 15 MPG. My T's have all been standard, the one 1912 has a dual intake/exhaust manifold, and I don't "hot rod". When touring, we sometimes run in the mountains of North Carolina but most of the time we are on fairly level ground. I don't have an odometer but most of our tours have very accurate mileage steps for the tour day.

1917 Touring - alum pistons, Z-Head, 10 tooth pinion, 15 mpg.

I don't know how many mpg my T's do, because none have speedometers. However, I can usually run all day on one tank of gas, which would be about 90 to 100 miles. I only need to fill up more often if I am climbing a lot of hills because of gravity flow.
Norm

You do not need a speedometer. Fill it with gas. Drive it 150 miles. Fill it with gas. Then do the math.

TOO DAMN FUNNY, LMAO!

All those so-called upgrades increase the ratio of positrons to neutrons as the fuel sloshes around in the tank. The resulting static electricity increases evaporation of fuel through the vent hole. That's where your gas is going. You need to hang a chain from the rear axle to drag on the ground and drain away the excess charge.

.ereh gniyd m'I

You didn't fill-up with gas from Walmart or did you?

Wal Mart gas is made from marmots!

I use a old Garmin GPS for a speedometer / odometer and actually keep a log of "Arthur's Travels." As an old pilot like Bob Coiro, I log my trips, the people who ride with me and maintenance done. Knowing the mileage helps me keep on top of maintenance better.

I log my trips...

On July 28, 1974, in Yautepec, Morelos, I filled my 1968 beetle that had 65876 miles on it. I paid 51 pesos for 35.7 liters of regular Pemex (1.43 pesos per liter). I keep a log book too.

David H.
How do you know exactly 150 miles without an odometer? And what are the odds of finding two gas stations exactly 150 miles apart? I suppose you could have someone follow you with a modern car, and then figure the mileage. But if the car runs a long distance on one tank and there are no leaks, why worry. My modern car tells me the mileage as I am driving and the average mileage. It keeps changing depending on how fast I go , whether going uphill or downhill or when I start out from a stop and when I am slowing down. It is never constant. So why worry about a slight increase or decrease in T mileage? To get a consistant comparison, you would need to go exactly the same speed, on the same route, in the same weather and driving conditions etc.
Norm

Congradulations.

Just out of curiosity what gear did you go to?

Don't ignore the affect of ambient conditions (weather, urban/highway driving) on gas mileage. Not sure when you took your readings but assuming it was these past months in Central Pennsylvania. Considering how weather conditions-atmospheric pressure, temperature and humidity-are factors that have an effect on air density which in turn could account for your mileage results . Cold air is more dense and requires a more fuel to maintain a proper air fuel ratio, a cause to drop fuel economy. Strange as it sounds, the more dense the air is the more drag on the vehicle; another loss in fuel mileage. The Model T isn't the most streamlined design.

I would expect that as the weather warms up you will see an improvement in you gas mileage. So keep your log and see how the weather may be affecting your mileage.

Pretty simple. You ‘hopped up your engine’.
Something usually changes when you do that. I wouldn’t worry about a fuel loss of that little.
Drive it and break it in and check again a few months later. If it’s running good with the expected improvement in get up and go drive it and have fun.

I've got my T almost off of the Gasolene, running on 85% water now, FIVE miles to the Gallon, but hey, water is cheap..
My Oddometer will not count the even miles so I could be off by a smidgen

Re;
I would expect that as the weather warms up you will see an improvement in you gas mileage. So keep your log and see how the weather may be affecting your mileage.
If he keeps driving, by time the weather warms up, the engine will be broke in and the MPG might be better anyway.

Cracked water is a very good fuel, if you can hold on to it .... but beware of that cheap-O heavy water. It will cut your fuel mileage while making your cylinders egg shaped and it will cause sand blisters on your tires. Many report that their hens no longer lay after they use heavy water and that donkeys lose their bray. It really should be banned, but Big Oil won't hear of it!

Whether you can hold on to cracked water depends on whether you keep it in a cracked pot.

.pu em gnikcrac si sihT

The best cracked pots are those made in Crakow back before the war...

TXGOAT2 wrote: ↑

Wed Apr 21, 2021 2:19 pm

The best cracked pots are those made in Crakow back before the war...

This thread is getting a getting potty

Dick, you will get better MPG if you simply switch to Imperial Gallons. You blokes are all being cheated!

Allan from down under.

Norm. Norm. Norm. No need to be that exact. It is only a model T. Take a ride of a certain distance and remember what road you used. When you get home plot it on google maps. Now you know your mileage. The rest is easy. Hey, if you want you could use regular one day and premium the next. Then let us know the difference. You live in the hills of CA, and that is included in your math. I live in the flats of WI, but I can hit some good hills if I want. We have hills made by glaciers and hills the glaciers never touched. Come on out and I will even let you drive a car. I know you have driven more T miles than I gave. Just no racing.

I use an app called “speedometer simple by Tevfik Yucek”. GOS speed, average speed, miles per trip, nice big analog gauge and a digital gauge. Also a compass.
And I generally get 20mpg or better with a 3:1 Ruckstel, Stromberg OF, HC head, aluminum pistons and oversized valves....on regular BP gasoline.
My Stewart speedo is in Russian Versts, so I marked it according to the GPS...55 Versts is 40mph.

You got to put clothes pins on your gas line and a magnet on your gas cap!

If you drive in reverse, does your fuel level increase? It only stands to reason that it should.

The best mpg is in my runningboard can. I cant count the miles I get from that one gallon of gas.