millage per gal

tenbroeck

I have a 41 8 cyl with 47k on it I had it rebuilt when it had 45k. comp is 100psi. I have overdrive and on the hiway I only get 12mpg. Tires are at 23 psi. I use 30w oil (NAPA). Vac is at 19 psi off manifold. any suggestions what I can do to get it higher? I hear people are getting 15-18 mpg.
     

Glowplug

Let the have you broken  in the engine?  New engine builds are notorious for rotten mileage

tenbroeck

what is the best way to brake it in? 

Glowplug

Breaking in an engine buy driving it... 

tenbroeck

well I have done that I have put 2k on it 

onerare39

23 psi tire pressure seems really low.  That may have some role in your MPG.

tenbroeck

I was incorrect on the tire pressure the are 32 psi. Carb was rebuilt by a person in Calf he does them all cannot remember his name right now. Front end was reworked by a person here that has been in business many years and does old cars. just frontend work. Brakes were adj this year. everything in dist is free but not sure how to tell if it is worn. Points and cond are new and set with feeler gauge not dwell not sure what dwell should be. Timing is set to spect not sure how much to advance it.  Wheel bearings  not tight I will check the grease. I do not have a vac advance on my dist. there was never one. car has been in the family since the 40's.  thanks for all the info I will double check what I can.    

squirrel

How fast do you drive on the highway?

On the ignition timing...you can advance it a bit if it does not ping, try from 4 to 10 degrees.

terraplane8

You may need an analyser to see what your mixture is, especially if you are some way above sea level or your mixture will be too rich. Maybe your timing is too retarded - using the vacuum gauge you can adjust that to get the max reading at idle then back it off a little then road test it for pinging. My '33 Terraplane 8 got 18.9mpg on the open road with mixed hills and flats, averaging 51.6mph calculated by time/distance with no overdrive.

tenbroeck

on state hwy I do 55. 

tenbroeck

what type of spark plug do you use? right now I have champion J8c

Kdancy

also, what type of gas are you using? go to non-ethanol if not using it already. 
as noted above, increase timing and back off if pinging is heard. 

tenbroeck

can not get non ethanol 

cheyenne7271

I guess I should be thankful I can get non-ethanol fuel here in west Texas. More freedoms taken away I guess, but we won’t go there.....

joe53HH

pure-gas.org shows the locations for non-ethanol in the US and Canada.