How do I up the MPG's on my Willys Jeep???

Discussion in 'Flat Fender Tech' started by mikec4193, Apr 4, 2012.

  1. Apr 6, 2012
    jwjeep60

    jwjeep60 in process

    Sedalia Mo.
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    20min per gal is what you should expect at 45 mph
    my f-134 did much better than 3gal/hr as it pulled a 7' field rake.
    the v6 wheeled for several hrs, I decided I should top off the tank before the next trail and it couldn't take 5gal from the jerry can.

    3gal/hr at idle is not right
    go in there and adjust idle mix, and timing so it will idle as low rpm as possible then turn the rpm back to 500rpm
     
  2. Apr 6, 2012
    duffer

    duffer Rodent Power Sponsor

    Bozeman, MT
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    I have to argue this point. You MAY get more "thorough" combustion but there is more to that than just a long stroke. The combustion chamber shape figures into the equation also and having a large pocket (valves) well removed from the spark travel does not promote either good mixing or flame travel.

    Every "exceptionally undersquared" gas engine I have ever used has had exceptionlly poor fuel economy, whether it be the 572 cid straight 6 in the FWD or the 443 cid 4 banger in the Oliver 99 (and both of these are overhead valves). I attribute most of this to both poor induction efficiency and the very high piston acceleration. The pistons have zero velocity at both TDC and BDC so the longer the stroke, the higher the piston acceleration for any given rpm and that does take energy no matter how you look at it. It also is the reason that you have to be extremely lucky to get more than 75-80k miles out of a ring job on most of these engines. The long stroke diesels have less problem with this because most of them operate entirely below 1700-1800 rpm.
     
  3. Apr 6, 2012
    JeepPower

    JeepPower Hopeless Gearhead

    Fort Mill, SC
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    I get the best mileage out of it when I shift at 2000 RPM or less, when accelerating.

    As said-- get an overdrive!
     
  4. Apr 6, 2012
    oldtime

    oldtime oldtime

    St. Charles,...
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    Here my description of the terms "extremely efficient engine" is relative only to the fuel octane that is provided.
    That's specifically inferring use of 66 octane.

    Yes this is quite valid !

    I got 80000 mixed useage miles on my last rebuild.
    My next Hurricane will like get notably better mileage.
     
  5. Apr 6, 2012
    sherpa

    sherpa Member

    Mooresville NC
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    The best thing can do is make sir the engine is in tip top tune. From valve and Carb adjustment to timing and plugs and keep up the maintenance. I drive a 360 powered cj so I feel try fuel milage pain also
     
  6. Apr 13, 2012
    w3srl

    w3srl Curmudgeon-in-training Staff Member Sponsor

    Pittsburgh, PA
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    I forget who said it first, but it certainly applies here. "Once you stop thinking of an early Jeep as a highway vehicle and start thinking of it as a street-legal farm implement it all starts to make sense." ;)
     
  7. Apr 13, 2012
    JeffsJeep04

    JeffsJeep04 Member

    Menomonie, WI
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    Can't think of a better way to sum it up...HA!
     
  8. Apr 16, 2012
    mikec4193

    mikec4193 Jeepless for first time since 2007....

    Mechanicville ny
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    Hi Everyone

    Thank you thank you and thank you again for all the insight. I have learned a couple of things here since I posted this question.
    1)These early flatfenders are more tractor than car....(I was actually hoping to being able to drive it to work but that may not happen now and thats ok too)...
    2)These little vehicles are not really made to any have kind of MPG's...they are what they are I guess....I was told years old from a cranky old designer guy I was working with "You cant polish a turd"....I think what he was saying was you cant make this old flatfender something that it isnt...

    So if I do get it so I can drive it on the road then we will have to see...I may have to move closer to work...or get more hours at my second job to pay the gas bill...or if I dont like it..park it on the lawn next to the other Willys Jeep I own...(I have learned these old Jeeps love to sit and sorta hang out in the yard...they dont cost anything when they do just sit..kinda of a win win deal for both of us....)

    Thanks again for all the insight
    MikeC
     
  9. Apr 17, 2012
    jeep2003

    jeep2003 Active Member

    vestal ny
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    i consider the savings in insurance more than enough to pay for everything else. My 87 blazer is over 1200$ my 67 jeep is like 200$ since its a classic. Cant complain about that!
     
  10. Apr 17, 2012
    68BuickV6

    68BuickV6 Crawl-O-Matic

    Chino, CA.
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    Dang Mike! What's your secret? The longer mine sits, the less interested it is in idling well, starting, running, warming up...need I go on? :rofl:
     
  11. Apr 18, 2012
    mikec4193

    mikec4193 Jeepless for first time since 2007....

    Mechanicville ny
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    Hey 68BuickV6

    You asked about my secret to letting stuff sit and idling and starting.... kinda simple I dont ever try to start them because I know they wont want to run anyways. I run a 1999 S10 pickup as a daily driver and thats all I ever drive. I work 2 jobs so I dont have a lot spare time and when I do get time I am usually grinding rust off of one of my piles of Jeep rust....To me these Willys Jeeps are toys....they dont cost me nothing once I get them done because I never drive them. I dont give them chance to cost me anything. What do some folks call them "lawn art". If you dont ever run them they dont ever have any issues. It is easier (a lot less stress too) to me to let them sit....then it is trying to keep the old heaps running.

    Thanks for asking.

    MikeC
     
  12. Apr 25, 2012
    DoubleBit

    DoubleBit Member

    East of Auburn, CA
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    Did any of the L or F head motors use a distributor with vacuum advance? My old F head does not have vacuum advance and I have toyed around with the idea of looking for a distributor that does. IIRC vacuum advance basically kicks in during high vacuum operation and can help with economy.
     
  13. Apr 25, 2012
    oldtime

    oldtime oldtime

    St. Charles,...
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    Yes both the L+F engines were at times equipped with Autolite vacuum advance distributors.
    These were never available on CJ's.
    These are standard on Willys SW, PU, FC and many industrial applications.

    Yes the vacuum advance distributor helps with fuel economy.
    Look for Autolite IAT 4008 (early) and IAT 4401 (late).
     
  14. Apr 25, 2012
    DoubleBit

    DoubleBit Member

    East of Auburn, CA
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    Ah, now that's interesting... First what's a "FC"?
    And, do they all use the same drive gear (you know like to fit with the cam's gear)?
    Good gawd, or is it a separate shaft... ? I need to go look...
    And did they operate on manifold or ported vacuum?
    I always kinda lean toward setting up on ported, but would certainly try the proper vacuum source first.
     
  15. Apr 25, 2012
    68BuickV6

    68BuickV6 Crawl-O-Matic

    Chino, CA.
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    The FC was the JEEP Forward Control pickup.

    [​IMG]
     
    Last edited: Apr 25, 2012
  16. Apr 25, 2012
    jwjeep60

    jwjeep60 in process

    Sedalia Mo.
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    entire dizzy swaps, but not bits and pieces
    ported vac
    a member here has modified a dizzy for vac advance and found it to be more hastle than improvement
    here is a early f-head vac advance.
    [​IMG]
    [​IMG]
     
    Last edited: Apr 26, 2012
  17. Apr 26, 2012
    DoubleBit

    DoubleBit Member

    East of Auburn, CA
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    Thanks for the FC and dizzy pix folks... After asking about the FC I sorta remembered those crazy looking rigs... There are a few of 'em buzzing around in my NorCal neck of the woods. And seeing the condition of that distributor sure reminds me that finding parts is not always so easy... I will keep my eyes open in the yards for one though... I mean, what's the likelihood that the advance diaphragm is any good? That's some danged old rubber/whatever... Where would one get their hands on a replacement diaphragm?
     
  18. Apr 26, 2012
    oldtime

    oldtime oldtime

    St. Charles,...
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    The pic shows a very early Autolite IGW with vacuum advance.
    I would definately shy away from that one.

    Use only MANIFOLD VACUUM supply at the base of the Carter carburetor.
    Ported vacuum is absolutely wrong for the Hurricane.
    Besides the stock Carter YF does not even provide for ported vacuum supply.
     
  19. Jun 18, 2013
    zoorda

    zoorda New Member

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    Propane conversion might be the path to more miles per dollar. Of course you would have to drive it enough to offset the cost of the conversion.
     
    Last edited: Jun 21, 2013
  20. Jun 19, 2013
    mikec4193

    mikec4193 Jeepless for first time since 2007....

    Mechanicville ny
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    Any idea what a propane conversion should cost for one of these vehicles???...I have a 1961-62 Willys cab in my back door yard that currently is a blank slate...nothing but a cab and front sheet metal...

    Any insight would be wonderful....

    MikeC
     

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