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Swapping Engine Questions

Discussion in 'Early CJ5 and CJ6 Tech' started by benebob, Oct 22, 2023.

  1. benebob

    benebob Member

    While my compression returned to solid numbers (actually shocking numbers for an engine that was seized and unseized with a bfh and wood blocks by the po) the oil consumption (around a quart of 15w40 in 100-150 miles) hasn't gotten better. Oddly it doesn't smoke insanely bad. Just a cloud after sitting at a light or deacceleration after some higher speed runs. Anyways I bought a spare engine when I bought the cj because it was close, well priced and will give me time to take my time rebuilding the original. Looks like I have a window to get 'em swapped before the weather turns nasty. The spare f134 was used in a cj2 or cj3 and is what looks like a much early spec then the f in my 65. Has a different carb set up and routing of the throttle, no pvc system just a pipe coming out by the fuel pump and a breather cap on the valve cover as well as a few other differences.

    This engine was rebuilt by the po who then decided to go with a modern v6 (exhaust valves and pistons done as well as a nos head). My questions are pretty basic so far as I want to order most of the bits I should need but as far as the crank ventilation would you put on a pvc valve or run it as it sits? Also this has a 8.5" clutch on it and the 65 has a 9.25" set up. Figured I should replace the clutch while I'm doing the swap but have only found OMIX or the like replacements for the 9.25 and they aren't exactly cheap where the 8.5" I can get some solid aftermarket makers for about 1/2 the cost. I do plan on plowing my driveway so would you simply go with a 8.5? Lastly the spare engine has a canister oil filter not the spin on. Is it worth swapping these or just run with the canister?
     
    Glenn likes this.
  2. Oldpappy

    Oldpappy A.C. Fults - Curmudgeon at large 2022 Sponsor

    A pipe coming out by the fuel pump?? I assume you mean it has a pipe coming out of the tappet cover as there is no place for a pipe to attach by the fuel pump.

    Early L134 (flat head) engines of WW2 Jeeps had what was called a "draft tube" for crankcase ventilation, as did a lot of vehicles of the era. The PCV system was developed for the Jeep because water could enter the engine through the draft tube when fording a deep enough stream.

    All F-134 engines had PCV systems, so it sounds like someone installed the old draft tube ventilation instead of doing it right.

    Since you are replacing the F-134 engine in your Jeep with this one, I recommend using the PCV system, carburetor, and throttle linkage from that one.
     
    53A1 and Glenn like this.
  3. PeteL

    PeteL If it wasn't for physics, and law enforcement... 2024 Sponsor 2023 Sponsor 2022 Sponsor

    I may be wrong but I think some early F-head pickups (1950-up) and wagon had the draft tube, prior to the release of the CJ5.

    The PCV concept was developed for military use, and also tapped the captured crankcase pressure as a way of waterproofing other systems in the vehicle.
     
    Daryl, Glenn, 47v6 and 2 others like this.
  4. benebob

    benebob Member

    Thanks guys that was kind of my thought (well aside from the carb possibly as it is an amazon special now, the spare came with 2 or 3 carbs but the po of it said he couldn't get it to not run rich which is why he put a v6 in it but I tend to think he wanted more power so that was his excuse). The draft tube looks like it belongs on the engine. Thoughts on the clutch? Is it worth going with a 9.25 for double the money and meh quality over a 8.5 luk or the like?
     
    Glenn likes this.
  5. Oldpappy

    Oldpappy A.C. Fults - Curmudgeon at large 2022 Sponsor

    Pete may be right about trucks and wagons retaining the draft tube, I do not know much about either, but it does surprise me.

    I should have said all F-134 engines used in Jeeps (CJ3B CJ5 M38A1) had the PCV system.
     
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  6. Jw60

    Jw60 That guy 2024 Sponsor 2023 Sponsor 2022 Sponsor

    I can vouch that the early F-head trucks and wagons had a draft tube, just a few years with the valve cover oil fill and basswords front plate.

    You basically have to tear both motors apart and use most of your original motor to make it work together. I never really slipped the clutch when plowing with the 134, and your not plowing wal-mart.

    When I went to my 4.3 my 134 was in need of a rebuild and it made sense to drop in the chevy from a cost perspective. You can get a running truck and adapter for the cost of the 4cyl parts.
    Then if you want to go crazy you can do the basic cam, compression, carb/ignition weights or TBI tune, and headers. The 4.3 uses the big sbc clutch and a flywheel equal to a 454. They have a lot of gusto to get a load moving.
     
    Glenn and vtxtasy like this.
  7. Dwins1

    Dwins1 Member

    My A1 does. It was built September of 52. So there were only a few hundred built before mine
     
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  8. Oldpappy

    Oldpappy A.C. Fults - Curmudgeon at large 2022 Sponsor

    Interesting. My 51 M38 had a closed system, so I figured that carried over into later Jeeps.
     
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  9. jeepstar

    jeepstar Well-Known Member 2024 Sponsor 2023 Sponsor 2022 Sponsor

    My 70 has a draft tube as well.
     
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  10. Oldpappy

    Oldpappy A.C. Fults - Curmudgeon at large 2022 Sponsor

    It didn't come that way.
     
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  11. benebob

    benebob Member

    Thoughts on going with a smaller clutch over the "heavy duty" and canister filter over the spin on? Just gotta run out some more gas before getting it ready to start stripping bits down.
     
    Glenn and Dwins1 like this.
  12. Oldpappy

    Oldpappy A.C. Fults - Curmudgeon at large 2022 Sponsor

    The 8.5" clutch will work fine.

    It is a matter of preference as far as the oil filter goes. Your year CJ5 would have originally had the spin on filter, but the canister filter was used on earlier CJs and all of the military Jeeps, they work fine, but are more of a mess to deal with.
     
    Glenn and benebob like this.
  13. Dwins1

    Dwins1 Member

    My A1 has the canister type. The way the oil goes through the filter it really is not doing much due to the outlet on the engine and small pipe that feeds it. I had a 53 M38a1 that someone took the canister type off and installed a Napa screw on setup.
     
    Glenn and benebob like this.
  14. Glenn

    Glenn Kinda grumpy old man Staff Member

    As I understand it the filtration is a bypass system by design so not all oil flow is filtered. Personally I think it does better than one might think it does.
     
  15. Dwins1

    Dwins1 Member

    this is how they are on the M38A1

    IMG_0478.jpeg
     
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  16. Oldpappy

    Oldpappy A.C. Fults - Curmudgeon at large 2022 Sponsor

    Dwins1,

    Very clean looking engine, but not sure what you are showing us. Oil filter is on the other side.
     
    Glenn likes this.
  17. PeteL

    PeteL If it wasn't for physics, and law enforcement... 2024 Sponsor 2023 Sponsor 2022 Sponsor

    But be aware the filters were different sizes and are not interchangeable.
     
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  18. oldtime

    oldtime oldtime

    I definitely would want the 9-1/4” clutch if I was planning to plow snow.
    That became the standard clutch size in November of 62.
     
  19. Jw60

    Jw60 That guy 2024 Sponsor 2023 Sponsor 2022 Sponsor

    I think my old 134 had the standard clutch. It did the job fine made a nice fuse if anything. I would take a luk clutch if available in either size.



    :whistle:
     
    benebob and Glenn like this.
  20. Oldpappy

    Oldpappy A.C. Fults - Curmudgeon at large 2022 Sponsor

    Snow plows, and enough snow to need one, are seldom seen in this part of the country, but there have been some fields plowed with the old Jeeps having the smaller clutch.

    If the flywheel is drilled for the larger clutch that might be a better choice, but the 8 1/2" clutch will get the job done.