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Cummins 4BT versions

Discussion in '1982-Present GM Diesel' started by Steve_87K5, Jun 18, 2004.

  1. Steve_87K5

    Steve_87K5 1/2 ton status

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    Italessi....your 4BT, does it have the counterbalance shaft? When I was looking at possible diesels for my K5, there was a good deal on a used 4BT out of a bread truck.

    (later decided on 6.2)

    I called Cummins and the rep told me that many of these bread truck 4BTs were supplied without a counterbalance shaft and have a lot of vibration. I happened to talk to a driver also, and he said the alternator bracket on his 4BT step van regularly broke off.

    What is your experience?
     
  2. mcinfantry

    mcinfantry 1/2 ton status

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    some MAY have been v-belts, ive never seen any. mine is serpentine and i see NO WAY for an alt bracket to break. i rode by the frito lay center where i bought it and he (the head area mechanic) was VERY VERY shocked to feel how little it vibrated, how much power it had and how good it fit.

    i even changed my 65amp 12si to a 108amp 21si with no bracket mods, none.

    the cummins has a GEAR driven powersteering pump! the belt only drives the alt and water pump. it runs cool enough with a stock (and small) m715 radiator that my taurus fan does not come on in 90+ heat at a standstill on the interstate

    ill answer any questions you want. i have no glow plugs, and its 2 wires to hook up. one from the alt, one to the fuel solonoid (and it can be bypassed to manual shutoff)

    its a 3.9l 4cyl diesel for those who do not know. cummins 6bt (read dodge ram) accessories fit and the performace upgrades also work

    i am turbo only, no inter or after cooler. id like one, but its not worth the conversion money right now, and i honestly have no complaints.

    my truck weighs 3780lbs on the FRONT axle, 2500lbs on the rear, for a total of 6280lbs. so i know im heavier than yall
     
  3. mcinfantry

    mcinfantry 1/2 ton status

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    im running michelin 1100x16 xl's

    id like to add i do fine on highway with 105hp at 2300rpm and 286ftlbs torque at 1600rpm. the truck is no speed demon, but gets out of its own way. i get 22mpg in the city, 24 on the highway at 70. i SHOULD get 30mpg at a constant 55mph to 60mph.

    i just got back from LBL Ky and ran all the trails in 4wd lo 2nd gear at 650rpm. rear is locked, front was an unlocked ELECTRAC.

    3 days of wheeling burned 5 gallons diesel. the gassers burned 30-40 gallons.


    it honestly drives like an auto, i cannot stall it. it will idle up a 18" STUMP. you let the clutch out and only use the brake to control speed
     
  4. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    [ QUOTE ]
    im running michelin 1100x16 xl's

    id like to add i do fine on highway with 105hp at 2300rpm and 286ftlbs torque at 1600rpm. the truck is no speed demon, but gets out of its own way. i get 22mpg in the city, 24 on the highway at 70. i SHOULD get 30mpg at a constant 55mph to 60mph.

    i just got back from LBL Ky and ran all the trails in 4wd lo 2nd gear at 650rpm. rear is locked, front was an unlocked ELECTRAC.

    3 days of wheeling burned 5 gallons diesel. the gassers burned 30-40 gallons.


    it honestly drives like an auto, i cannot stall it. it will idle up a 18" STUMP. you let the clutch out and only use the brake to control speed

    [/ QUOTE ]

    I found I had about the same experience wheeling in Moab with my 6.2. Pick your line, select gear, let out clutch and let the truck pick its way over at idle. It will not stall in low range. I used about $10 worth of diesel for 2 1/2 days of wheeling there...

    As for weight, my Jimmy is about 200 lbs lighter...but when weighed my truck was empty and had no spare tire. Mine is about 400 lbs ighter over the front wheels and a couple hundred lbs heavier over the rears.

    Rene
     
  5. mcinfantry

    mcinfantry 1/2 ton status

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    im glad to hear you are close in weight!

    i figure another 250lbs for troop seats, i dont have a spare, 275lbs for just me! and tools and i hit 7000+ real real quick.
     
  6. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    I figure if I add the cage and trail junk, but lose the hardtop, doors and tailgate I can squeak in at about 5800 in 'trail trim'.

    With all the tin on plus all gear and my skinny ass I'd be close to 6500 lbs.

    Wheeling with a diesel and a manual tranny is too friggin cool. I'm still used to struggling with a carb'd 350...and that just took the fun out of wheeling for me.

    Rene
     
  7. BlueBlazer

    BlueBlazer 1/2 ton status

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    The guys I go wheeling with dont believe me when I tell them how easy my rig is to drive on a trail. The only time I push down the clutch is to upshift, I even start it in gear if I need to. Gas engines are good for mud and mud only IMHO.
     
  8. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    Preach on brother Tyler!! /forums/images/graemlins/thumb.gif

    Rene
     
  9. Steve_87K5

    Steve_87K5 1/2 ton status

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    The 4BT I looked at was a V belt system. The rep also told me that the 4BT w/o counterbalance shaft is designed for stationary applications, where it is bolted to the floor.

    Did you consider the Herc diesel for your M715? (BTW, I had a 715 assigned to me in the Air Force in 1970, a radio truck, very harsh suspension, monster rear leaf springs, gas engine)

    There is a company in Clinton, OH, National Diesel, IIRC, specializing in 4 cylinder diesels used and rebuilt. I paid them a visit s few yrs back to look at several different 4 cyl for my K5. Deere, Herc, Cummins and Perkins.

    The 4 cyl Perkins had an accy drive shaft sticking out of the right rear side, extending forward along the block; it drove, among other things, an air compressor. It was an exposed shaft.

    Have you pulled a trailer with your 4BT? My K5 is 6250 lbs empty, and with enclosed 20ft trailer, I usually weigh about 12 to 15 000 lbs GCVW (hauling machinery).

    Can anyone explain difference between inter and after cooling?
     
  10. BlueBlazer

    BlueBlazer 1/2 ton status

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    Aftercooling covers any type of cooling the air charge after the turbo, air to air aftercoolers and jacket water aftercoolers. I believe when most people refer to intercoolers, they mean an air to air type. Where I work, we use the terms ATAAC (air to air aftercooler) and JWAC (jacket water aftercooler) to describe what type of system is used. By the way, ATAACs are better when you can get lots of airflow (like on a truck or machine) and JWACs work good if you can have a seperate cooling circuit for the aftercooler like on a large engine.
     
  11. mcinfantry

    mcinfantry 1/2 ton status

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    i have not put a hitch on yet. i plan on replacing the 16cm turbo with a 9cm one. supposedly the dodge guys sell them cheap as they are too small for bombed 6bt's
     
  12. imiceman44

    imiceman44 1 ton status

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    [ QUOTE ]
    The 4BT I looked at was a V belt system. The rep also told me that the 4BT w/o counterbalance shaft is designed for stationary applications, where it is bolted to the floor.

    Did you consider the Herc diesel for your M715? (BTW, I had a 715 assigned to me in the Air Force in 1970, a radio truck, very harsh suspension, monster rear leaf springs, gas engine)

    There is a company in Clinton, OH, National Diesel, IIRC, specializing in 4 cylinder diesels used and rebuilt. I paid them a visit s few yrs back to look at several different 4 cyl for my K5. Deere, Herc, Cummins and Perkins.

    The 4 cyl Perkins had an accy drive shaft sticking out of the right rear side, extending forward along the block; it drove, among other things, an air compressor. It was an exposed shaft.

    Have you pulled a trailer with your 4BT? My K5 is 6250 lbs empty, and with enclosed 20ft trailer, I usually weigh about 12 to 15 000 lbs GCVW (hauling machinery).

    Can anyone explain difference between inter and after cooling?

    [/ QUOTE ]

    I have the perkins 6cylinder Turbo, it has the same shaft you talk about and it drives the vacuum pump that runs my brakes.
    As for weight, I haven't weighed it yet, but I know from the book that my engine alone is 1400lbs, how heavy is the 4bt?
    My engine is great in the fact it doesn't need electricals to run it.
    Mechanical lift pump, injection pump, and the only reason I need electrical is for the starter and lights.
    /forums/images/graemlins/thumb.gif
    And I love idling anywhere I go, I also have the Manual. /forums/images/graemlins/pimp1.gif
    I think I will need to step up from 3.08 though if I want to go bigger than 35" tires, I am thinking 4.10 and 40" tires.
    That should put me in 16% underdrive meaning more crawling capability.
     
  13. Stomper

    Stomper ΜΟΛΩΝ ΛΑΒΕ GMOTM Winner

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    I believe my 4bt is around #700
     
  14. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    [ QUOTE ]
    My engine is great in the fact it doesn't need electricals to run it.
    Mechanical lift pump, injection pump, and the only reason I need electrical is for the starter and lights.


    [/ QUOTE ]

    That is exactly what I love about my 6.2. /forums/images/graemlins/waytogo.gif

    Rene
     
  15. Pookster

    Pookster 1/2 ton status

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    /forums/images/graemlins/bow.gif /forums/images/graemlins/bow.gif /forums/images/graemlins/bow.gif

    [ QUOTE ]
    [ QUOTE ]
    My engine is great in the fact it doesn't need electricals to run it.
    Mechanical lift pump, injection pump, and the only reason I need electrical is for the starter and lights.


    [/ QUOTE ]

    That is exactly what I love about my 6.2. /forums/images/graemlins/waytogo.gif

    Rene

    [/ QUOTE ]
     
  16. mcinfantry

    mcinfantry 1/2 ton status

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    [ QUOTE ]
    [ QUOTE ]
    My engine is great in the fact it doesn't need electricals to run it.
    Mechanical lift pump, injection pump, and the only reason I need electrical is for the starter and lights.


    [/ QUOTE ]

    That is exactly what I love about my 6.2. /forums/images/graemlins/waytogo.gif

    Rene

    [/ QUOTE ]

    i went cummins as i have NO glow plugs. the motor has a electric fuel solonoid, which can be bypassed and i can uses a manual on/off cable, and the injector pump is set up for it.
     
  17. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    You got me on the glow plugs and the manual shut off...but I only need the glow plugs when it's dead cold. If it's been running any length of time it'll flash up just fine without them.

    With the manual tranny I could also 'bomb start' my truck, although I haven't tried that yet /forums/images/graemlins/smile.gif

    At any rate, it's one hell of a lot simpler than any gasser I've had.

    Rene
     
  18. mcinfantry

    mcinfantry 1/2 ton status

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    i agree. the damn thing either runs, or doesnt. ill never go back to gas
     
  19. AZTimT

    AZTimT Registered Member

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    Italessi, I have a few questions... I just purchased an 84 GMC K30 with a 6.2/400/205 configuration as well as a 98 cummins 6bta/2wd nv4500 combo and I already have a divorced right hand drop np205 and want to convert this truck to a configuration not too different from yours.

    My first question is about the difficulty of mounting the np205 or more specifically making the brackets for it... by any chance do you have any brackets like that pre-fabbed?/forums/images/graemlins/shocked.gif Yours looks really nice and it sure would save my poor welder from the torture of being put to use by me on at least one part of the project!

    Second, I was wondering if that disc brake on the rear output was for regular use or emergency only and how well has it worked for you?

    I have been a huge diesel fan for years and I am finally going to have 2 of my own after I swap the 6.2 combo into my 78 blazer and successfully finish the GMC (Got My Cummins) project. I drove the 84 K30 all the way from Colorado to Arizona without any electrical/charging system due to a fusible link being burnt on the starter solenoid. That one deed alone made me realize just how valuable not needing spark plugs really is! I kinda feel bad about converting a truck that only has 38,000 original miles on it, but then again, what better vehicle for such a worthy engine as the cummins!? /forums/images/graemlins/grin.gif On that note... if anyone is gonna be looking for a 12,000 mile ZZ4 350 crate motor with holley projection and a 10 spline 465/205 combo please let me know as I will be pulling that all out of my 78 soon. Not for sale yet, just giving a heads up, cuz it is one powerful motor but not the diesel I have been dreaming of.

    Tim
     
  20. mcinfantry

    mcinfantry 1/2 ton status

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    [ QUOTE ]
    My first question is about the difficulty of mounting the np205 or more specifically making the brackets for it... by any chance do you have any brackets like that pre-fabbed? Yours looks really nice and it sure would save my poor welder from the torture of being put to use by me on at least one part of the project!


    [/ QUOTE ]

    i dont have any, but its not that hard. use some angle iron for the mounts and channel for the frame to frame mounts. i can get better pics if needed.

    [ QUOTE ]
    Second, I was wondering if that disc brake on the rear output was for regular use or emergency only and how well has it worked for you?


    [/ QUOTE ]

    its a highangle driveline e-brake. its emergency only. i liked my original brake band and drum better, but this works OK.

    you can call me anytime and its easier to talk than type

    225 445 6223
     

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