Register now to get rid of these ads!

HORRIBLE milage from my six.

Discussion in 'The Hokey Ass Message Board' started by Muffler Bearing, Jan 16, 2007.

  1. Muffler Bearing
    Joined: Aug 22, 2006
    Posts: 79

    Muffler Bearing
    Member

    im driving a stock '54 chevy 210. ive replaced all of the usual ignition components but it was still dog ass slow and got horrible milage. i bought a rebuilt carb from holley and now its not quite as dog ass slow, but my milage tops out at about 14mpg.

    im just racking my brain trying to figure out what the problem is with it. i tried leaning it out with the automatic choke, it seems to run better but then it wont start when cold.

    maybe i need new jets? i dont know much about carbs or how to read the plugs to figure out the mixture. the carb is a rochester with an automatic choke.

    thanks for any suggestions.

    -j
     
  2. HEATHEN
    Joined: Nov 22, 2005
    Posts: 7,591

    HEATHEN
    Member
    from SIDNEY, NY

    Is it a stick or a Powerglide? The 'glide cars really weren't known to be mileage champs.
     
  3. If your plugs are wet or sooty then you've got carb probs. Plugs should be dry.
     
  4. DrJ
    Joined: Mar 3, 2001
    Posts: 9,418

    DrJ
    Member

    Check the mechanical advance advances the full 13º it's supposed to and the vacuum advance advances the full 10º it's supposed to.
    If they don't, mileage will suffer big time.
    Check initial/idle timing with a strobe light on the flywheel ball mark.

    14-22 mpg is typical/common on those engines though, so don't expect miracles.
     

  5. rodknocker
    Joined: Jan 31, 2006
    Posts: 2,267

    rodknocker

    hows your exhaust flow
     
  6. retro54
    Joined: Apr 1, 2004
    Posts: 736

    retro54
    Member
    from PA

    last time I checked I got 20-21 with mine, when driving it daily
     
  7. GMC BUBBA
    Joined: Jun 15, 2006
    Posts: 3,385

    GMC BUBBA
    Member

    A tune up on these engines always included a valve adjustment and checking the contact point gap and mech advance plus vac advance.
     
  8. Bugman
    Joined: Nov 17, 2001
    Posts: 3,483

    Bugman
    Member

    Hows your front end allignment? Tires properly inflated? Brake drums rotate freely?
     
  9. Muffler Bearing
    Joined: Aug 22, 2006
    Posts: 79

    Muffler Bearing
    Member

    tires are inflated properly and front end is aligned.

    my exhaust is fine as far as i know, nothing is kinked. i put in a new muffler a year ago or so and new manifold gaskets about a month ago.

    ive replaced the points, condenser, cap, rotor, and plugs. i have no tyet tried adjusting the valves because i thought the '54 powerglide motors had hydraulic lifters. correct me if im wrong. point gap was set to the 'new' specs then after a week i re-set the gap to the 'used' specs even though it was pretty damn close.

    how do i check to make sure the advance is working properly?

    im getting between 9 and 14mpg... 14 is when i drive like an old woman... and this is my daily. i drive about 25-30 miles a day.

    -j
     
  10. Hardware
    Joined: Dec 18, 2005
    Posts: 91

    Hardware
    Member
    from West Coast

    Do a compression test on each of your cylinders. I did one on my 225 slant 6 Mopar a while back when I did a tune up. All my cylinders were a little low, but one in particular was about half of the pressure of the others. My engine was a total dog, burning lots of gas and running really rough even after a tune up. I got another head from the junk yard and rebuilt it with all new parts and hardened exhaust seats and now my car runs like a top. Burns way less gas, idles super smooth and has good power. When I pulled the old head off there was so much carbon build up in the head around the valves I could hardly believe it ran at all before.
     
  11. Shifty Shifterton
    Joined: Oct 1, 2006
    Posts: 4,964

    Shifty Shifterton
    Member

    Advance units can be tested as follows

    Mechanical advance- remove the cap. Grab the rotor and twist both directions. Does it feel spring loaded in one direction, and snap back to it's rest postion? If so, your mech advance is probably working. If the rotor is locked solid, remove it and free up the springs and weights underneath it.

    Vacuum advance. Apply vacuum with a vacuum pump, see if the vacuum canister moves the rod coming out it's back. If you have no vacuum pump, try moving the rod by hand, then cover the vacuum port, and when you release the rod, it should pull a vacuum on the port opening and stay in place until you take your finger off the port.

    Good Luck!
     
  12. pitman
    Joined: May 14, 2006
    Posts: 5,108

    pitman

    Check each of the brake drums after slowing to a stop using the engine's compression. See if any of them are on the warm side...
     
  13. HEATHEN
    Joined: Nov 22, 2005
    Posts: 7,591

    HEATHEN
    Member
    from SIDNEY, NY

    Checking the vacuum advance on a 235 is easy, since it turns the whole distributor when it advances. Open the hood, stand on the passenger side, and reach over the valve cover and rev it up while you stare at the distributor--it should twist in a counterclockwise direction. As I said in my first post on this thread, Powerglide cars didn't pull the mileage that the three speed cars did; that old slushbox sucks up a good percentage of what horsepower it's got. Chevies of that vintage are notorious for burnt valves. Maybe you've got one or two that aren't bad enough to cause a noticeable skip yet, but are still robbing power. As a couple of the other guys said, do a compression test.
     
  14. Skimmer
    Joined: Jul 31, 2005
    Posts: 1,105

    Skimmer
    Member

    My 6 in my 51 Chevy pickup aint good either 10-12 to the gallon got a holley 2 barrell nTH350 autobox..........i think its the way the 6's are...Juicy
     
  15. Muffler Bearing
    Joined: Aug 22, 2006
    Posts: 79

    Muffler Bearing
    Member

    thanks for all of the info.

    i am planning on rebuilding a head for this motor as soon as time and funds permit. i will be doing a compression check soon as well.

    i have revved the motor a little this morning and watched the distributor twist a little, i also moved it by hand when the motor was off and it springs right back to its normal position. this leads me to believe that the adavnce is working correctly, however, i still want to take the distributor apart because its prpbably pretty dirty in there.

    is it just the powerglide that is a power/milage hog or is it pretty true with all automatic transmissions? i would love to swap a manual but at 6'5" its already hard enough as it is to get my legs around the steering wheel and to the pedals, throw a clutch into the mix and it might take all of the fun out of driving this car. i plan on keeping it automatic. any suggestions for transmissions/gearing that would improve milage?

    i do not think that the brakes are dragging, but i dont remember checking it last time i had the car in the air. i will be working on the brakes pretty soon and will make sure i check that.

    -j
     
  16. Cyric30
    Joined: Jun 21, 2006
    Posts: 108

    Cyric30
    Member
    from AR

    hum
    coil hooked up correct IE not wired backwards, guy told me about it a bit back vehicle ran but lost power and gas miles stunk (i honestly dont know if he was joshing me or not But hay maybe it helps)...but that was with a MSD coil & ignition box with Electro Distrib...dont know if this would aply or not
     
  17. HEATHEN
    Joined: Nov 22, 2005
    Posts: 7,591

    HEATHEN
    Member
    from SIDNEY, NY

    Yes, most of the early automatics really did suck up fuel mileage potential. Look in the letter sections of early '50s Hot Rod or Motor Trend magazines, and you'll see a few "why does my Powerglide/Fordomatic get such dismal mileage" questions. I once had a '51 Buick Dynaflow car that got a whopping 5mpg--guess what got a for sale sign put in the window? As far as gearing goes, you've already got a 3.55:1 rear, which is the best you'll do without swapping in an open drive rear, at which point you'd have to lose the Powerglide anyway. By comparison, my first '53 had a '58 235 in it with dual carbs, dual exhaust, and a Mallory dual point with a three speed and 3.70:1 rear, and it got an honest 20mpg at 70mph on the highway. Around town, it always managed 15-16 mpg.
     
  18. LUX BLUE
    Joined: May 23, 2005
    Posts: 4,407

    LUX BLUE
    Alliance Vendor
    from AUSTIN,TX

    waitaminnit...14 m.p.g. is bad?

    I would be excited to make it out of the single didgits...
     
  19. cruisinkruty
    Joined: Jan 22, 2006
    Posts: 314

    cruisinkruty
    Member

    The best thing ya can do for a 235 is throw the stock distributer away and upgrade to an H.E.I. then increase your plug gaps to .045. If the carb is right,you will notice a smoother idle,better acceleration and improved gas mileage. A bigger match to light the fire always helps.....
     
  20. Muffler Bearing
    Joined: Aug 22, 2006
    Posts: 79

    Muffler Bearing
    Member

    electronic spark would be nice, just read about that on the stovebolt site. ...something to add to the mile long list of things to do with this car after i convert it to a 12v system.

    -j
     
  21. Muffler Bearing
    Joined: Aug 22, 2006
    Posts: 79

    Muffler Bearing
    Member

    can i get some more info on hardened exhaust valve seats?

    ill be asking the machinist about it next time i see him, different types or anything i need to know about them going into my six?

    -j
     

Share This Page

Register now to get rid of these ads!

Archive

Copyright © 1995-2021 The Jalopy Journal: Steal our stuff, we'll kick your teeth in. Terms of Service. Privacy Policy.

Atomic Industry
Forum software by XenForo™ ©2010-2014 XenForo Ltd.