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cummins or navstar swap?

Discussion in '1982-Present GM Diesel' started by camiswelding, Jul 4, 2004.

  1. camiswelding

    camiswelding 1/2 ton status

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    I have my 1989 mint condition v3500 with a tbi 454/th400 and am getting 10 mpg empty/6 loaded pulling 9k pounds...
    Ive been looking at a diesel swap.. (fordcummins.com)

    Has anyone here done either swap?..... seems like the navstar motor would be easier to fit... while the cummins makes more power...
    anyone know companies that make swap parts OTHER than fordcummins.com
    thanks
    cam
     
  2. mtn. burb

    mtn. burb 1/2 ton status

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    I'd like to know too. The thought of all that torque is mega appealing.
     
  3. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    I think the Ford uses a wider frame rail arrangement because of the width of the Navistar. It might not physically fit without major frame mods...

    I'd consider a 6.5TD if you're also considering the Navistar (6.9 and 7.3 TD) Power is comparable in stock form.

    The Cummin's swap has been done...might try a google search or one of the many other diesel forums.

    The GM diesel is nowhere near as anemic or 'bad' as you've heard. Tons of misinformation out there that should be taken with a grain of salt IMO.

    Rene
     
  4. Diesel Dan

    Diesel Dan 1/2 ton status

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    Ahem, <font color="red">CUMMINS </font>.

    Just a recommendation.
     
  5. camiswelding

    camiswelding 1/2 ton status

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    I had a 91 sub with the 6.2....purchased new... fuel mileage was fabulous but the engine wasnt peppy.... and heavy towing was out... gale banks (who was a friend) did his magic to it but I was always worried about the long term reliability.... the 700r4 gave up at 50k miles (warrantied) but I wasnt happy with it after that and sold it...
    I had heard that the navstar might be too wide... although its 444 ci... and my 454 fits in there easily... the navstar and the 6.2/6.5 arent even in the same league in my opinion... even the new 6.5 hummer block,,, its still an engine with cast pistons etc etc etc...
    Im still interested in more info... I understand the cummins requires a 3 inch bodylift AND firewall massaging to fit.... Im wondering if this is true?
    cam
     
  6. imiceman44

    imiceman44 1 ton status

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    [ QUOTE ]
    I had a 91 sub with the 6.2....purchased new... fuel mileage was fabulous but the engine wasnt peppy.... and heavy towing was out... gale banks (who was a friend) did his magic to it but I was always worried about the long term reliability.... the 700r4 gave up at 50k miles (warrantied) but I wasnt happy with it after that and sold it...
    I had heard that the navstar might be too wide... although its 444 ci... and my 454 fits in there easily... the navstar and the 6.2/6.5 arent even in the same league in my opinion... even the new 6.5 hummer block,,, its still an engine with cast pistons etc etc etc...
    Im still interested in more info... I understand the cummins requires a 3 inch bodylift AND firewall massaging to fit.... Im wondering if this is true?
    cam

    [/ QUOTE ]

    The cummins does need a body lift or clearance in the hood.
    As for the firewall, you can get away without touching it if you remove the mech fan and go with 2 slim electric fans.
    I have the 5.9l perkins, same size and same dimensions and that is how they fit it in my K5. I have one inch between firewall and back of engine, and 1 inch between the water pump pulley and the radiator.
    /forums/images/graemlins/dunno.gif
     
  7. Diesel Dan

    Diesel Dan 1/2 ton status

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    [ QUOTE ]
    The cummins does need a body lift or clearance in the hood.
    As for the firewall, you can get away without touching it if you remove the mech fan and go with 2 slim electric fans

    [/ QUOTE ]
    I don't know why they won't clear the hood. The only CTD swap into a late model IFS truck that needed a body lift for hood clearance was due to the fact that he ran a water/air after cooler that came out of a bus. That sits right on top of the intake manifold and is quite tall. Many people have installed them into 2wd suburbans without body lifts. Go to the TDR and look under cummins conversions.

    From what I've seen yes on the fans. I was planning on electric fans, but recall seeing a pick of a 2wd '70s crewcab with CTD and mechanical fan on ebay a while back. Should have bought that truck for $2500 or so.
     
  8. mcinfantry

    mcinfantry 1/2 ton status

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    well my 4bt oil pan is VERY close to the pumpkin, and its as tall as a 6bt. i would assume a 2wd suburban does not have a differential in the front for the oil pan to hit, nor would i expect much flex, but i could be wrong.

    ifs box is bolted to the frame so again, i would assume that there is no flex into the oil pan, but again i may be wrong as im not familiar with the swap
     
  9. K30CJ

    K30CJ 1/2 ton status

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    Mine had firewall mods, just with a 3 lb. sledge, no cutting. No body lift was needed, but mine's the older front end which doesn't slope down like yours. IMO, if you're gonna go to the trouble and cost to swap, do it right - use the Cummins. /forums/images/graemlins/waytogo.gif
     
  10. imiceman44

    imiceman44 1 ton status

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    [ QUOTE ]
    well my 4bt oil pan is VERY close to the pumpkin, and its as tall as a 6bt. i would assume a 2wd suburban does not have a differential in the front for the oil pan to hit, nor would i expect much flex, but i could be wrong.

    ifs box is bolted to the frame so again, i would assume that there is no flex into the oil pan, but again i may be wrong as im not familiar with the swap

    [/ QUOTE ]

    Yeah my pan is also modified, it actually sits next to the pumpkin now. /forums/images/graemlins/dunno.gif
    But to hold 22 QTs I guess it needs to be big.
    /forums/images/graemlins/yikes.gif
     
  11. Diesel Dan

    Diesel Dan 1/2 ton status

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    [ QUOTE ]
    But to hold 22 QTs I guess it needs to be big.


    [/ QUOTE ]
    /forums/images/graemlins/thinking.gif, my '96 only holds 12-14 with filter change.
     
  12. imiceman44

    imiceman44 1 ton status

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    [ QUOTE ]
    [ QUOTE ]
    But to hold 22 QTs I guess it needs to be big.


    [/ QUOTE ]
    /forums/images/graemlins/thinking.gif, my '96 only holds 12-14 with filter change.

    [/ QUOTE ]

    Mine holds 22Qts and that is with the dual 1qt oil filters.
    It's better for soot control so I am happy with it.
    /forums/images/graemlins/waytogo.gif
     
  13. Diesel Dan

    Diesel Dan 1/2 ton status

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    I wonder what application your oil pan is for?
    Sounds like larger medium duty or stationary power unit.
    My '96 has a rear sump that clears the D60, not by a whole lot either.

    Cam,
    Easiest swap would be a '89-93 4wd dodge/ram. Auto would give you a 727/np205, A518(OD)/np205 with RH drop. The VE pumps only need a single wire and the earlier ones are non-intercooled. For the stock power you could most likely run a I/C motor as a non-I/C and still be ok.

    If you like manual trans than do a NV4500. Have it rebuilt with GM output and you can use your NP205.
     
  14. camiswelding

    camiswelding 1/2 ton status

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    thanks dan...
    I understand you have to notch the frame on one side... go with electric fans or do alot of radiator placement mods...and in my case I was going to keep a stoutly built th400 with a gear vendor od...
    I also understand the years you suggested are the easiest to adapt to the chevy wiring..
    thanks
    cam
     
  15. imiceman44

    imiceman44 1 ton status

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    [ QUOTE ]
    I wonder what application your oil pan is for?
    Sounds like larger medium duty or stationary power unit.
    My '96 has a rear sump that clears the D60, not by a whole lot either.

    Cam,
    Easiest swap would be a '89-93 4wd dodge/ram. Auto would give you a 727/np205, A518(OD)/np205 with RH drop. The VE pumps only need a single wire and the earlier ones are non-intercooled. For the stock power you could most likely run a I/C motor as a non-I/C and still be ok.

    If you like manual trans than do a NV4500. Have it rebuilt with GM output and you can use your NP205.

    [/ QUOTE ]

    Well assuming you do remember mine is a Perkins TD, it's from a 67 farm tractor, it has an aluminum pan that was cut and a few pieces added on for clearance.
    I am working on making a one piece aluminum pan that would clear everything and not leak through the multiple joints /forums/images/graemlins/dunno.gif
     

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