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Projects Trying to squeeze a little more gas mileage from a 235

Discussion in 'The Hokey Ass Message Board' started by junkyardjeff, Sep 20, 2018.

  1. junkyardjeff
    Joined: Jul 23, 2005
    Posts: 6,988

    junkyardjeff
    Member

    If I can find a 8 inch pig with 3.70 to 4.11 gears reasonable I will buy it.
     
  2. Put a business name on the doors and write the truck and the fuel off your income tax.
     
  3. junkyardjeff
    Joined: Jul 23, 2005
    Posts: 6,988

    junkyardjeff
    Member

    Due to some freezing rain that is forecasted the liquid salt has been put on the roads so I will worry about it in the spring,I hope it rains by tuesday since I am heading to Daytona Beach in the Sunliner.
     
  4. junkyardjeff
    Joined: Jul 23, 2005
    Posts: 6,988

    junkyardjeff
    Member

    I was able to fill it up today and on that trip last fall it got 14.6 miles to the gallon,I was hoping it would do better but with the scored bearings and crank that might be the best it will ever get and should wait until I get the better 235 in and see what it gets. I did advance the timing some so I will check it again after I run this tank out.
     
  5. 57JoeFoMoPar
    Joined: Sep 14, 2004
    Posts: 4,142

    57JoeFoMoPar
    Member

    You'll get better milage with a small block.
     
  6. junkyardjeff
    Joined: Jul 23, 2005
    Posts: 6,988

    junkyardjeff
    Member

    That is probably true,thought of putting a V8 in it but I like the sixes and be different.
     
  7. firstinsteele
    Joined: Jun 13, 2013
    Posts: 877

    firstinsteele
    Member

    Jeff, I can tell you some things that MIGHT help. Some OT. Some not. My 1950 Buick regularly gets 20 on the hwy, running 60-65. Last around town, short hwy tank was 16.

    Ben
     
  8. junkyardjeff
    Joined: Jul 23, 2005
    Posts: 6,988

    junkyardjeff
    Member

    When it was screaming at 50 it got better gas mileage and now that it can cruise 80 without coming apart it gets worse so I know the engine is not at its sweet spot,I do not have the money to get some steeper gears to work better with the o/d so I will just have to deal with it. I had been timing it to the factory specs but decided to time it with a vacumn gauge and seems to run better so I will see how it does.
     
  9. KenC
    Joined: Sep 14, 2006
    Posts: 225

    KenC
    Member

    I have a theory about the problem with adding OD to older cars. I think the resulting low cruise vacuum causes the carb to get into the power enrichment area. various method where used, vacuum sensing pistons with metering rods, power valves etc. I wish there were different calibrated springs for those to try. I suspect that if one could match the cruise vacuum to an enrichment circuit cutoff it would really help. Too bad we can't fit the various Holley power valves to older carbs.

    If we dip into a modern bag of tricks and install a air/fuel ratio meter we could verify or refute that guess.

    I'll be dealing with this in a few months as the old flat dodge comes together.
     
  10. junkyardjeff
    Joined: Jul 23, 2005
    Posts: 6,988

    junkyardjeff
    Member

    I have changed the jet and put in a weaker power valve spring and it helped.
     
  11. junkyardjeff
    Joined: Jul 23, 2005
    Posts: 6,988

    junkyardjeff
    Member

    I think my mileage test was flawed since I lost around 1/4 of a tank in one of my daily drivers that sat over the winter so I presume I lost some in the 37 too,this crappy new gas evaporates about as much as water so I will test it again with the fresh tank now that its starting to get nice enough to start driving it again.
     
  12. You have the answer to your steeper gear canundrum at your gearshift...what happens if you let it rev higher in 4th gear?
     
  13. junkyardjeff
    Joined: Jul 23, 2005
    Posts: 6,988

    junkyardjeff
    Member

    The short glass packs get too noisy so I never really went too far above 50 in 4th.
     
  14. Yes, but does your gas mileage improve by getting it into the rev range it likes?
     
  15. junkyardjeff
    Joined: Jul 23, 2005
    Posts: 6,988

    junkyardjeff
    Member

    I have not let it run in 4th on longer trips above 50 so I do not know but will try it but maybe after I change the mufflers,the ones I have are getting too obnoxoius or old age setting in and I cant stand it any more.
     
  16. junkyardjeff
    Joined: Jul 23, 2005
    Posts: 6,988

    junkyardjeff
    Member

    Filled it up again and its getting 15.7 around town,has not been put in 5th even at speeds above 50 so I think its happy spining a little. Going to take a little trip on two lane roads at speeds around 60 and not in 5th to see how it does,it probably needs at least 3.73 gears but I have the speedo accurate so it just will not go into 5th below 65.
     
  17. junkyardjeff
    Joined: Jul 23, 2005
    Posts: 6,988

    junkyardjeff
    Member

    Took it on the longest highway trip since I got it on the road and it definately needs 3.73 or 4 .11 gears with the o/d,with the vacumn gauge on and it was very hard to keep the vacumn above 10 even at 70 and 75. At 65 in 4th the gauge was reading about 15 so I know those engines were designed to spin much more them modern engines,big swapmeet coming up next weekend so I will see what I can find.
     

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