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Engine swap question

Discussion in 'Early CJ5 and CJ6 Tech' started by p38L5, Mar 22, 2012.

  1. Mar 22, 2012
    p38L5

    p38L5 Member

    Napa CA
    Joined:
    Feb 5, 2012
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    94
    Which V6 is the easiest swap for the F134 in an M38A1? I am taking my 1953 M38A1 down to frame and adding the following: 2.5" lift BDS springs, 33" wheels/tires, saginaw manual steering, dana 27 front end with powr-lok - warn hubs - disc brakes - 5.38 gears, dana 44 rear end with powr-lok - disc brakes - 5.38 gears. I have a brand new T90 with a dana 18 and a warn overdrive.

    The F-head in my jeep was overhauled a few years ago and runs great; I just figure eventually I'll want to swap it out - why not do it now? If I was to swap engines, I would like to do it with the least amount of modification to the engine compartment. My questions are: Would I use the T90? Would I use the stock radiator?

    The other possibility would be to do all the mods with the exception of the engine swap, build the engine over the summer and swap it out next winter; and if I did that, would I need to redo the saginaw steering?

    I am open to all ideas, suggestions, critiques, etc.

    Many thanks,

    g
     
  2. Mar 22, 2012
    duffer

    duffer Rodent Power

    Bozeman, MT
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    Ahhh, standing on the top of that very long, very steep, very slippery slope.R)

    And as always, the answer will have a lot to do with what use you plan for it. If I were doing it, it would be a 4.3 and a SM465 just because I am a Chevy fan and those are both easy to come by and work really well (actually, if I was really doing it, there would be another 383 sbc in there). New radiator-yes. D18 and OD-keep. Saginaw should be ok but may influence your exhaust options.

    Oh, the crampons and ice axe will not help. You are about to go for a ride.
     
  3. Mar 22, 2012
    Warloch

    Warloch Did you say Flattie??? Staff Member

    Falcon, CO
    Joined:
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    5,466
    While I agree that the 4.3 and 465 would be my first look, I also have several 225s and a 231 sitting in the shop that I would throw in with the 465 as that is what is available here - 4.3s are a bit tough to find.

    Easy is relative - and so is cheap(er). See what you have available in that class and look real hard into a swinging pedal setup and the complexity of what your asking. The pedals make alot of other things easier to fit. It will cost some money to go to a 4 speed, but it will cost to adapt the T90 as well. Limiting the number of adaptors is a good cost and complexity limiter as well to look into.

    BTW - I'm with Duffer "slip, slide and away" pops into my head :)
     
  4. Mar 22, 2012
    duffer

    duffer Rodent Power

    Bozeman, MT
    Joined:
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    My feelings on swaps like this gets back to what oldtime likes to harp upon: a synchronous system where everything works together rather than a cascade of weak links. If you embark on this adventure, you will eventually be either replacing (with flanged version) or modifing (full float conversion) the rear axle and most likely the D27 will get replaced with a D30 at some point.

    And being you are at bare frame and doing a saginaw, I would plan on adding a power version along with the motor swap-no better time to set it up and you will really like it off road.

    As mentioned above in Chuck's post, trying to do this without hanging pedals is a pain in the butt and really limits your part options. With disc's, I am going to guess power brakes will be going on anyway shortly after you get it on the road so may as well bite the bullet and do it up-front while everything is easy to get at.
     
  5. Mar 22, 2012
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Medford Mass USA
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    Maybe the other guys will disagree with me here, but I don't think staging this (ie do all you can and leave the F134 in place) will help you much. You could maybe do the hanging pedals now, and a Saginaw steering conversion.

    Supposedly the Buick V6s (225 and 231) fit the engine compartment best, because of the front-mounted distributor. The other popular replacement, the 4.3L Chevy, puts the distributor at the back of the manifold, and makes firewall interference more of a consideration. But I believe both will fit without engine bay modification.

    You could also consider a modern 4-cylinder. The 153 cid Chevy inline 4 and its industrial/marine counterpart the 3.0L/181 cid four are said to be really easy to fit in the Jeep engine compartment. And they have the Chevy small block bell pattern, so they are easy to adapt to the T-90. If you look, you can probably find a used GM-to-T90 adapter on eBay, in the for-sale ads in the Jeep forums, and other likely places (R&P?). Other peppy 4-cylinders, like the AMC 150, the Pontiac 151, and the Pinto 2.0L/2.3L would be tidy swaps too.
     
  6. Mar 22, 2012
    duffer

    duffer Rodent Power

    Bozeman, MT
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    Absolutely agree with Tim. All that staging will really buy you is tearing it down twice. However, this may be a case where you should just put the 134 back in a run it until it dies-while stockpiling the pieces for the conversion and doing it one to several years down the road. You have to have a lot of time and $ available to do a swap quickly, at least if you are going to do it right. Having the engine and trans set up and sitting on the garage floor before you start would be a very big plus.
     
  7. Mar 22, 2012
    pgte3

    pgte3 Member

    Guilderland, NY
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    Sep 29, 2011
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    96
  8. Mar 22, 2012
    jpflat2a

    jpflat2a what's that noise?

    Hermosa, SD
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    Jul 30, 2003
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    Okay, I'll go against the flow...
    To use the T90, disassembly and installation of the correct length input shaft is needed.
    You'll need an adapter and associated components. The T90 is okay behind the V6.
    You could keep the stock radiator, only relocating the lower hose outlet to the opposite side.
    You could do the Saginaw conversion now, and if you plan on headers with the V6, and careful design, no changes would be needed with the V6.
    The drivers frame motor mount may need to be notched for shaft clearance.
    The floor pedals can be retained.
    Your axle choices and ratios will work.
    Of course, all of these choices are for you to make.
     
  9. Mar 22, 2012
    Warloch

    Warloch Did you say Flattie??? Staff Member

    Falcon, CO
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    The only thing Jim left out (as I have done that as well) is you normally have to bend the brake pedal to get it to clear the BH (at least I always seemed to). You can run it for years that way and revisit the rest when you know what you want.

    BTW - that is with the 225/231 V6s.
     
  10. Mar 22, 2012
    shmober

    shmober Member

    eureka ca.
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    May 10, 2011
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    I have the Chevy 153. It's better than the L head I had in my flatty, but it still lacks power. Easy swap. I'll be selling it soon. Intake and exhaust are hard to come by if you start with the marine motor. Not much if any aftermarket support.
     
  11. Mar 22, 2012
    oldtime

    oldtime oldtime

    St. Charles,...
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    Thanks Duffer, that's my "QUE".

    Yes a COMPLETE SYNCHRONOUS SYSTEM is the goal.
    Basically I suggest you take your good sweet time at this.
    The more you KNOW, the fewer your mistakes will be.

    Here is a very incomplete article with a few concepts that may or may not be of help to you:
    http://z4.invisionfree.com/CJ3B_Bulletin_Board/index.php?showtopic=2591

    The optimum engine to install is the greatest single decision you will have to make.
    Because the mechanical force that it harnesses from the fuel yeilds the greatest impact upon the complete system a a whole.
    This is basically why the referenced article is incomplete todate.
    IMHO "engine analysis" alone potentially becomes an extremely exhaustive topic.
     
  12. Mar 22, 2012
    Jw60

    Jw60 Sitting up n buckled down. 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Sedalia MO.
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    1. search through previous builds.
    2. research your options.
    3. decide what works best for you.
    4. review previous builds that are similar and the problems they experienced
    5. do everything at once. (no sense redoing something to make the next item work)

    biggest factor is fuel injection, 4.3 would have a clear advantage
    just for reference my swap took 6 weeks from engine out to putting down the road with 6hrs total on a rented engine hoist
    and most of that was waiting for replacement t-90 bearings, I tell myself that is PDQ for 1 man in a driveway.
     
    Last edited by a moderator: Mar 22, 2012
  13. Mar 22, 2012
    Warloch

    Warloch Did you say Flattie??? Staff Member

    Falcon, CO
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    I don't know on the FI any more. There are several real good self learning FI systems that just pop on the 4bbl with minimal wire and sensor issues. Something real nice like that for folks that don't want to fight the whole new types of setups (depends all on what you like).
     
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