153 Chevy lump installed.

Discussion in 'Flat Fender Tech' started by Truckedup, Nov 26, 2012.

  1. Dec 4, 2012
    oldtime

    oldtime oldtime

    St. Charles,...
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    Very interesting.
    So what exactly is the distance from the center of crankshaft to the center of the water pump ?

    F-134 = 11"
    D225 = 6-1/2"
    I-4 / 153 = ?"
     
  2. Dec 4, 2012
    duffer

    duffer Rodent Power Sponsor

    Bozeman, MT
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    I would have guessed it is the same as both Chevy small and big blocks: 7.04" No reason a mechanical fan will not work. A custom shroud may be necessary. I still believe if you really want to move air, a mechanical fan remains the best option.
     
  3. Dec 4, 2012
    Mr. Gangrene Jeans

    Mr. Gangrene Jeans I See Voices&Hear Visions

    Kansas City
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    My stock DJ-5A with a 153cid L4 has the same issue. Center of the fan is just slightly above the bottom 1/3rd of the radiator. Shroud would have to be custom, way custom.
    PO had a cobbled up electric fan in front of the radiator. Took it off, don't like seeing them thru the grille. Currently using a plastic mechanical fan from a Chevette. Probably have to rig an electric when I start driving it.
     
  4. Dec 4, 2012
    Truckedup

    Truckedup New Member

    Western NY state
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    It's a touch more than a SBC at about 7.25 inches.The water pump center is about 5.5 inches above the stock lower radiator mounts welded to the tubular cross member. The steering bell crank is right there also. That means any mechanical cooling fan only gets 5 inches of draw below the fan center.And with a lower radiator tank, the core may only see 3 inches of fan.The 153 is also tilted up more in front than the stock flattie engine.
    I don't think a mechanical fan will be effective at low speeds......so I figured an electric fan before the swap was started.
     
  5. Dec 4, 2012
    Truckedup

    Truckedup New Member

    Western NY state
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    This is what the lump looks right right now. Fits very nicely and looks kinda stock.

    [​IMG]

    The stock gas pedal is still in place with a linkage similar to GM 60's stuff running over head to the sideways Mopar slant 6 Holley.

    [​IMG]
     
  6. Dec 5, 2012
    gunner

    gunner Member

    Washington state...
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    The carb looks good on there- did it take much to adapt it in?

    Also, the slant six is 225CID, bigger than the 153 chevy, did you re-jet it?
     
  7. Dec 6, 2012
    Truckedup

    Truckedup New Member

    Western NY state
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    The carb fit as is...I know it a good one and have no others and also want to get it running .The 153 uses 2-15/16 mounting pattern which is the same as Mopar and the larger GM 6's.I did drill and tap new holes in the intake so the carb can be used without a bell crank linkage like the original Rochester. A 225 Slant 6 and the the 153 4 cylinder have the same displacement per cylinder.From past experience with modified inline 6 engines,the jetting should be ok. The Holley will likely tolerate being mounted sideways..but if not I'll either replace it or turn it bowl forward and fabricate a bell crank.
    I looked at a lot of radiators..I don't want to alter the nice stock radiator.2005 ish Scion radiator is the perfect size and the aftermarket aluminum 2 row versions have enough cooling capacity. It looks easy to mount also. They don't have a built in filler and cap,but I have cap set up that mounts on the top hose . 108 bucks to my door in a few days
     
  8. Dec 12, 2012
    Truckedup

    Truckedup New Member

    Western NY state
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    Took a ride today to with the new engine.Zips right along,at least compared to the 134 flattie. Carburation is a bit lean with no manifold heat and 30 degree outside temps.The radiator is from a 2004 ish Scion. It's a two row and the core is about the same size as the stock Willys radiator..And weighs a lot less.For now I cut down an old nylon fan fan. Doesn't heat up at idle..but I bet it will in summer....
    And something interesting.,,The Jeep now has a steering wobble at around 35-40 MPH. Never had one before the swap no matter what the speed or road surface.Sticking my head out the side the front wheels flopping from side to side. I wonder if having less weight on the front end has something to do with it.OH well.something to work on...

    [​IMG]
     
  9. Dec 12, 2012
    oldtime

    oldtime oldtime

    St. Charles,...
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    The displacement per cylinder is irrelevant.
    The bottom line is that slant 225 requires greater CFM than the I-153.
    That means the primary venturi size is normally larger on the slant 225 carburetor.
    If large primary venturi used on a smaller displacement engine that will cause the engine to run lean.
    That's because the air flow is increased disproportionately to the calibrated fuel metering restrictions.
    Lean fuel burning eventually manifests as burned valves.

    This is an interesting thread.
    I'm seriously intersted in the potential fuel efficiency numbers at around 60 mph.
     
    Last edited: Dec 12, 2012
  10. Dec 12, 2012
    Truckedup

    Truckedup New Member

    Western NY state
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    Not exactly based on experience with inline 6 engines.For instance,three Harley Davidson side draft carburetors that feed two 40 inch cylinders work quite well with out drastic rejetting on 230-300 cube inline 6 engines with 40-50 inch cylinders.And it proven in drag racing that a 300 cubic inch 6 requires more throttle bore area than the same size V-8.
    With the stock jetting in this slant 6 carb ,the plugs are bone white in the 153.A touch lean like I said.But it runs well,you can floor the accelerator at 20 mph in high gear and it moves right out.No sign of over carburation. The stock 153 intake has the carb mounting studs three inches on center.This is the largest throttle body light duty single barrels found on 230-300 inch 6's. USA OHV inline 6's were low speed engines with limited breathing so no real need for bigger high speed carbs like a V8
    Fuel usage at 60 mph will be not so good with stock 5.38 gears.:)
     
  11. Dec 12, 2012
    04sd2

    04sd2 Member

    Lehigh Valley, PA
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    Nice build.
     
  12. Dec 13, 2012
    oldtime

    oldtime oldtime

    St. Charles,...
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    I'm not familiar with the specifics of the carburetor that your using but fully disagree with misconceptions about carburetion.

    CARBURETOR SWAPPING BASICS

    1) Mainly the fuel CFM requirement is determined by total displacement, not by individual cylinder discplacement.
    Greater displacement requires increased CFM via larger primary venturi.
    Ideally you want a carburetor that was engineered for a specific displacement.
    When swapping carburetors from one engine to another the standard practice is to remain within 5% of the target engine displacement.
    Ideally a carburetor is designed for all of the engines unique characteristics. So...

    2) Secondly the CFM requirement is determined by optimum crankshaft velocity.
    Lower crankshaft velocity = lower CFM requirements via smaller primary venturi.
    Higher crankshaft velocity = higher CFM requirements via larger primari venturi.
    Due to design not all engines operate most efficiently at the same crankshaft velocity.

    3) In part an engines CFM requirement is determined by volumetric efficiency.
    The volumetric efficiency is nothing more than an engines overall design efficiency relative to its displacement.
    The design efficiency entails both the inward and the outward flow.

    Example: The standard I-4 153 reaches maximum efficient crankshaft velocity at a typical 2400 RPM.
    US built I-6 engines range anywhere from 1250 RPM to 2800 RPM.
    Typically most I-6 engines reach maximum efficient crankshaft velocity at around 1800 RPM.
    The standard 225 Dodge I-6 reaches maximum efficient crankshaft velocity at a whopping 2800 RPM.
    The 225 Dodge I-6 has both increased displacement and velocity over that of the GM I-153.
    This specifically implies that the 225 Dodge I-6 requires much greater CFM than the GM I-153.
    Therefore the 225 Dodge I-6 carburetor's fuel / air mix is much different than required for the GM I-153.
     
    Last edited: Dec 13, 2012
  13. Dec 13, 2012
    Truckedup

    Truckedup New Member

    Western NY state
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    I don't know who wrote the article above but perhaps he needs to stop by my house and drive this 153 engine with the 225 Mopar carburetor and then think about what's written................Then think about replacement carbs like Q Jets that are listed for use on GM engines from 300 to 400 plus cubic inches . And it's all the same carb. Same for generic Holley 600 cfm 4 barrels,out of the box they provide the proper fuel metering for many different engines.
     
  14. Dec 13, 2012
    oldtime

    oldtime oldtime

    St. Charles,...
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    No need to be personal.
    Seems that we fully disagree on carburetor design and function.
    My understanding is simply that one size does not fit all.
     
  15. Dec 14, 2012
    Truckedup

    Truckedup New Member

    Western NY state
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    It's not a personal attack but a true statement.I didn't mean to sound like a jerk.But I have done a lot of hot rodding , swapping carbs,and have practical experience that's contrary to the statement you posted.
    But I have a bigger problem than carburetors.The Jeep now has the dreaded 40 mph front end shimmy.It had no shimmy at any speed on any road before the swap. The suspension was not touched during the swap that took about two months.The front end was done last summer,new kingpin bearings with proper preload,no worn parts anywhere. The only change was about 100 pounds less weight on the front end.
     
  16. Dec 14, 2012
    oldtime

    oldtime oldtime

    St. Charles,...
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    No hard feelings on my end.
    Sometimes the written word does not stimulate the envisioned thought correctly.
     
  17. Jan 12, 2013
    Truckedup

    Truckedup New Member

    Western NY state
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    The weather is ok the last few days so I've been driving on the road some.The Chevy 153 is smoother on the road than the Willys engine even though it's sitting on the Willys motor mounts.I can run along at 55 MPH (3500 rpm) with no sounds or feeling of distress from the engine. Not that I use it on hiways but it's nice to be able to run 55 for a short time if necessary.Obviously the acceleration is better also.
     
  18. Jan 13, 2013
    gunner

    gunner Member

    Washington state...
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    I'll be looking at a round fender with a 153 Chevy in it tomorrow. Your thread has me making the effort to drive a couple hours to check it out. It's a minor project at the right asking price. Be interesting to see if there are any other upgrades besides the 153 and 11" brakes. Owner says it runs great.
     
  19. Jan 13, 2013
    Truckedup

    Truckedup New Member

    Western NY state
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    The best part about the swap is my 2A still has all the Jeep character, 4 cylinder engine,easy steering and marginal brakes :D Well,it stops if you press real hard...Better brakes are not a bad idea if the Jeep has an overdrive or different gearing and higher cruising speed.
     
  20. Jan 15, 2013
    Bob-The-CJ

    Bob-The-CJ Member

    Waxahachie, Texas
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    A first glance it does look weak, but when you really look it is actually quite beefy and I agree that should be fine.

    I guess it is sort of an optical illusion anyway, I think it is the contrast in colors
     
    Last edited: Jan 15, 2013

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