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77 Cj5 Inline 6

Discussion in 'Intermediate CJ-5/6/7/8' started by Danefraz, Dec 1, 2021.

  1. Dec 1, 2021
    Danefraz

    Danefraz Well-Known Member 2021 Sponsor 2020 Sponsor

    Chico CA
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    FIL has a 77 with the inline 6. 43k original miles on the ticker, my wife and her sisters probably accounted for a lot of those back in the 80’s and 90’s.

    Rumor has it our smog rules will change to 1980 so this can have the smog junk deleted, again.

    looking at may be adding fuel injection and putting the headers back on.

    seems the old headers, intake and carb that really made it run good were probably traded years ago, so considering FI…

    anyone gone this route yet? Parts list, gotchas, thoughts and musings?

    thanks.
     
  2. Dec 1, 2021
    hudsonhawk

    hudsonhawk Well-Known Member 2020 Sponsor

    North Texas...
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    I did a GM TBI on an '83 258 using stock intake and exhaust. My intake already had a plug I used for the AIT sensor.
    You will need:
    • Rochester carb to GM TBI adapter plate and GM air filter housing.
    • O2 sensor in the exhaust.
    • Air Intake Temperature sensor
    • electric fuel pump (I had good luck with a Ford frame rail mounted one.) as well as return line from the TBI to the fuel tank.
    • mechanical fuel pump block off plate
    • lots of patience with the wiring. I custom built mine and did not use a kit
     
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  3. Dec 1, 2021
    hudsonhawk

    hudsonhawk Well-Known Member 2020 Sponsor

    North Texas...
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    On the TBI, you will have the Idle Air control valve, Throttle position sensor and wiring for the injectors.
     
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  4. Dec 1, 2021
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor 2021 Sponsor 2020 Sponsor

    Medford Mass USA
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    No personal experience. Why not swap in a 4.0L HO? Factory Bosch MPI with knock sensor and spark control, way more power, superior fuel economy to any modified 232 or 258, EFI or not. The 4.0L HO makes close to the same top-end power as a 360. This is a T-150 Jeep? Needs a CPS which can either be relocated to the front of the engine, or you can cut a hole in the factory bell housing for the 4.0L flywheel. Novak used to offer to modify your bell housing for a CPS.

    https://www.quadratec.com/products/17009_1000.htm

    JMO - if I wanted TBI, unless I wanted the adventure, I'd likely do this - https://www.holley.com/brands/holle...ection/sniper_efi/sniper_efi_bbd_for_jeep_cj/

    Junk the iron manifolds and fit a header (if wanted) and the superior '81-up 258 aluminum intake. I'm running manifolds from an '85 CJ on my J10, and they almost bolt up. I needed to notch the PS bracket slightly. You may not need to notch with headers - it's the exhaust manifold that slightly interferes. The later exhaust manifold is superior too - much smoother than the original log type, almost streamlined. You lose the carburetor heater that uses exhaust gas, but there is an electric heater in the aluminum manifold. Several ways to enable that; maybe not needed in a temperate climate.
     
    Last edited: Dec 1, 2021
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  5. Dec 1, 2021
    neohic

    neohic Gentleman Jeepist

    Woodland Park, CO
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    Have a talk with Kevin up at Performance Fuel Injection up in Michigan. He makes a good bolt on kit that uses GM Howell injection, an aftermarket HEI distributor, all the sensors, and a computer that makes it talk together nicely. I’ve put a few of his kits on vehicles and there usually isn’t much fuss. When I did my 258 a few years ago I had it torn down and then back to running within 9 hours.

    https://pfisys.com/
     
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  6. Dec 1, 2021
    bigjohn

    bigjohn Member

    Kelso Wa
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    I really need to reread that thread. I think I’m finally tired of that 1bbl In off camber situations on my 258 and that price isn’t bad. I read your conversion a few years ago I think.
     
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  7. Dec 2, 2021
    Chilly

    Chilly Active Member

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    Before spending on TBI maybe try a good carb? A MC2100 might surprise you, and unless this is a daily driver would the EFI really be worth the trouble? It's a 77 with 43k miles. Will he even put 1000 mi/year on it? Pretty high $/mi to upgrade something he apparently doesnt care to drive much.

    Engine is low miles so I cant see swapping it. Putting on a well-tuned MC2100 and a good ignition system would be my choice. And the manifold Tim recommended if you want to go a step further.
     
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  8. Dec 2, 2021
    Danefraz

    Danefraz Well-Known Member 2021 Sponsor 2020 Sponsor

    Chico CA
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    Engine swap not going to happen.

    he has had it since new.

    TBI is a good upgrade that when coupled with a few other similar upgrades lets it run better and is less than some folks spend on black wheels. :poke:

    miles per year isn't really an issue any more except when talking to the insurance guy.

    It has been thru the Rubicon jamboree something like 5 or 10 years in a row, back in the day, but is mostly a Sunday ice cream getter these days.

    it has taught my niece and nephew to drive a stick, and my daughter is next - she might even get to drive it to school now and again (especially if my ‘69 Heep project stays stalled out much longer).

    Much appreciate the different kits and suggestions.
     
  9. Dec 2, 2021
    '74Renegade

    '74Renegade Active Member

    Fair Oaks, CA
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    I think the Howell kit is 50 state smog legal if that makes a difference. I wouldn't hold my breath for the 1980 and prior smog exempt rule unless you have an inside scoop.
     
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  10. Feb 8, 2022
    Danefraz

    Danefraz Well-Known Member 2021 Sponsor 2020 Sponsor

    Chico CA
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    Reviving the dead thread.

    headers fir the 258 look like as varied as knuckle pudding recipes, some with spaghetti looking piping.

    FIL brought it up today that the old headers were split, and he had dual exhaust with glass packs that kept your feet warm.

    anyone have a favorite header config for the I6? Singles or duals, no matter. with probably going magna flow vs the old cherry bombs…

    Pulling off the smog and going to let it breathe.
     
  11. Feb 9, 2022
    Madmike8

    Madmike8 New Member

    Tennessee
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    I did a Megasquirt install about 15 years ago on a 2.3L Ford. Things have gotten a lot better now in terms of software and hardware. Now I have a '75 DJ5 with a 232 that I planned to use a Speeduino ECU on. When I was still planning to use the 232, I was planning to use an early 4.0L EFI intake that can be modified to work on the 232/258. Then I found the 232 was a bit too messed up, so I'm probably just going to use a 4.0l engine. I'm just planning a simple batch fire/ wasted spark setup. Both the Megasquirt and Speeduino can use the Flywheel based CPS, but I will probably move to a 36-1 wheel mounted on front. Use Tunerstudio autotune with a 14point7 Spartan2 wideband O2 setup to help get me close on the tune.

    Things that I haven't tried, but am now considering is either a EFI intake fuel pump conversion kit or a engine bay mounted Surge tank with a built in EFI fuel pump. DJ5 gas tanks aren't normal CJ5 tanks and are hard to find, so I'm considering the surge tank a bit more closely.
     
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  12. Feb 9, 2022
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor 2021 Sponsor 2020 Sponsor

    Medford Mass USA
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    Which intake manifold do you have?

    The '81-up manifolds are much improved over the earlier "siamesed" iron manifolds. The intake is an aluminum 2V meant for the Carter BBD, but it's easily adaptable to the Rochester 4.3L/305/350 TBI throttle bodies (Megasquirt?), or a Holley pattern 2V. Holley makes a Sniper TBI that's meant to replace the BBD, which would be a particularly easy project with this manifold.

    The '81-up exhaust manifold is iron, but it's redesigned to be much smoother, lighter and flow better. It's still a single outlet manifold, so you won't get the 3-3 extraction you should have with tubing headers. But it's cheap, and a lot better than stock. You'll also save money at the exhaust shop, with a free-flowing single exhaust. And you'll have more freedom of routing, to keep the floor cooler. IME the exhaust system of a Jeep takes a lot of abuse, and simpler is better.

    There's also the possibility of the 4.0L HO head, which uses a tubing header from the factory. It's not split - going into a single exhaust - but it's supposed to be good.

    '78 Duraspark distributor, TFI cap and wires, and a MSD module.
     
    Last edited: Feb 9, 2022
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  13. Feb 10, 2022
    Danefraz

    Danefraz Well-Known Member 2021 Sponsor 2020 Sponsor

    Chico CA
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    Stock intake, 1977, stock carb. Haven't had a chance to looksee at it.
     
  14. Feb 10, 2022
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor 2021 Sponsor 2020 Sponsor

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    '77 CJ has a 1V Carter YF and a 1V iron intake. If you have the stock exhaust manifold, the manifolds bolt together with an exhaust gas carb preheater flap built in. The wagons and J10 got a 2V BBD in '77 on an iron intake manifold, but the CJ lagged until 1979 when the 232 and YF were eliminated. All had the bolted-together iron manifolds until 1981.
     
    Last edited: Feb 10, 2022
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