gas mileage

4tford

4tford

Well-known member
Looks like I get about 13 mpg Canadian or 10mpg USG. All in town miles. Sure does not seem like much.
 
is tail pipe black and sooty? if so carb is running rich, plugs should be a tan color, if black and sooty once again running to rich, is choke all the way off? check choke with cleaner off to make sure, is the air cleaner clean? is timing slow? set it at 3 to 6 degrees btdc, are tires the right size? not to small? what is your rear end ratio? I should have ask what year at the beginning of my post, you should be getting 13 to 15 mpg
 
Good points to check. I have built a lot of flatheads but this is the first in a car since I was a kid. Big learning curve. lol
 
I think 10 mpg just driving around town is pretty normal. That could probably be as high as 15 mpg on the highway. You could check some of the things WestCoast said just to be sure. I improved my gas mileage noticeable by just reducing the size of my carburetor jets one size. Gotta be careful though. Too lean makes it run hotter which can be worse than poor gas mileage.
 
It seems to me that the gas mileage on the old engine is way too low. My 53 with the stock 239 gave about 22 mpg (canadian) on the highway and 17(city).
I hope I did the conversion correctly. I used this car for daily transportation to school in the early 1960's and was very concerned about costs.It was a great car and I paid only 60.00 for it in 1963. It was solid black, Customline and a messed up roof paint job. I sanded the roof and brushed on a white paint job and it looked fabulous. Was nice and cool too!

A friend gave me fender skirs that clipped on. Very cool!
 
Hmm, I'd say 10 miles per gallon is low. I just took my '36 on a 200-mile trip a few weeks ago and averaged 15 miles per gallon. Of course this journey was mostly on secondary roads cruising at a brisk 55 or 60 miles an hour passing through small towns here and there, stopping at the occasional red light. However, I wind it up pretty high (the V8 loves to sing!) plus it was leaking a little fuel out the carb lid. With the new Holley pressure regulator I just installed I reckon the economy will go up a little bit more. My engine is 251 cubic inches and I have a 3.78 rear end. Check your carb jets and make sure you're not leaking any fuel, which is more than just wasteful -- it's a fire hazard.
 
As has been stated there are so many factors influencing economy but a well tuned pre war Ford with 3.78 diff and 221 motor should give 20 miles per imperial (Canadian) gallon at 50/55 mph.The heavier post war sedans with the 239 motor about 3 mpg less.My experiences only. Geoff
 
Gas mileage depends on allot of things, including the driver. However, the early ignition systems did not have a very good advance curve in cruise for mileage, compared to the Load a matic when working properly. Engines converted to the GM distributor can take advantage of the lean burn during cruise. While the stock ignition doesn't.
 
Might also suggest you check tire pressure. I run 32+ cold.
My 39 Standard coupe has a 4.11:1 axle (was originally a V8 60),
it still maintains better than 17 mpg, at 55 mph or less, as the engine
begins to sing above that.
 
My '36 roadster will get 21-22 on the highway. It is about 265 CI being a .060 over Mercury block. The mileage comes from a 3.25 rear with OD trans as well as a Chevy distributor.

A good advance curve and tall gearing really makes a differance! It also makes the car a joy to cruise in at 65 mph.

John
 
40grit said:
My '36 roadster will get 21-22 on the highway. It is about 265 CI being a .060 over Mercury block. The mileage comes from a 3.25 rear with OD trans as well as a Chevy distributor.

A good advance curve and tall gearing really makes a differance! It also makes the car a joy to cruise in at 65 mph.

John
Click to expand...

Petty sure that's drinking more gas than a stock and in good order late Merc.
Too much gear can use as much gas as too little gear. Your 3.25 becomes a 2.27! Personally I think this is too much gear. Ideal I believe is cruising at the torque peak of the engine mpg wise. Be interested in what rpm your pulling at 65?
Martin.
 
You must log in or register to reply here.
Back
Top