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just bought an 83 diesel

Discussion in 'The Garage' started by general blaze, Sep 4, 2005.

  1. general blaze

    general blaze 1/2 ton status

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    well. i am not to impressed with the power. what can be done to give these things some more off the line get up and go????
     
  2. diesel4me

    diesel4me 1 ton status Premium Member

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    its not meant to be fast..

    If its a 6.2,drive it for awhile,before you decide to do anything--when I first got my 82 K20 with a 6.2,I thought it had a 2.5 in it-- :eek1: --its NOT a drag racer by any means!...but if I floor it with the brakes applied,it WILL eventally spin and smoke the tires!--after awhile,I got used to it--the diesel has a much different power band than a 350 gas motor..you'll notice it SOUNDS like its dogging off the line--but watch the speedometer,and you'll see its going 35-40 in no time..mine goes about the same as my 2wd C10 with a 305 in it..not fast,but kids on bikes dont pass me either! :rolleyes:

    Many diesels have high gears in the axles,like 3.08's..good for fuel mileage,poor for power,and acceleration--4.10's and 4.56's are good choices for big tires..you dont want the motor screaming TOO fast on the interstate either though..have to select an "all around" gear, according to tire sizes..

    I'd give your truck a new air filter(very important to be clean on a diesel--they suck in 10 times the air a gas motor does,even at idle!--any restriction kills power)--and a new fuel filter,(read procedures BEFORE changing,to avoid "Airlocking" the fuel line!!)--and add some fuel conditioner--then see if its got any more grapes...you might be pleasantly suprised! :laugh:

    If your still unsatisfied--the gears can be swapped,or a turbo added..but both are costly,labor intensive mods to do..I'm happy to leave mine stock,and live with its limitations--it plows great,gets much better fuel milage than the 400 SB I had in a similar truck--and its able to run on vegatable oil if diesel is too costly..plus I dont have to wait in long lines at the gas pump--because I dont NEED gas!... :laugh: :crazy: Welcome to the wonderful weird world of diesels..!!
     
  3. general blaze

    general blaze 1/2 ton status

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    hey thanks for the info. ya i tried to get the rears spinning the other day and it just wouldnt do it. not even on dirt. i cant even do a donut. it does climb up hills just fine.

    it is a 83 k5 with a 6.2 diesel.i will post some pics later if i can.

    i heard these things have no problem pulling whatever you want. but it seemed like my truck had a hard time pulling its own fat ass over a hill on the freeway. i was wide open throttle and i think i was just over 45 mph. just wondering if there was anything i can do to get this to go a little faster. i guess i could look for some different gears at a local scrap yard. thanks angain for all the info. feel free to let me know anything else that you can think of... like i said this is my first diesel. i used to have a gmc jimmy 1973 with a small block 350. almost the same truck but drives totally different.
     
  4. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    Sounds like you got some really tall gears under that truck. I have no problem spinning my 39.5's on dirt, gravel, wet pavement etc. Haven't really tried on dry pavement though. As for full throttle, I haven't used that for a coons age...in fact I still have a throttle stop installed. I installed the throttle stop to help it pass emissions and haven't felt any need to remove it yet. It stops the throttle at about 60% of WOT.


    Assuming you have a 700R-4 you can easily run 4.11-4.56's with most tire sizes quite easily...and still get good fuel mileage.

    Rene
     
  5. diesel4me

    diesel4me 1 ton status Premium Member

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    gears...tune up!

    I'd "tune it up" with new air and fuel filters,and add some injector cleaner,then try it out again..it might be you have the 3.08 or higher ratio rear ends that kill all the power.(common in the 80's trucks)...you should at least be able to spin the tires in dirt! :eek1: ..if it has big tires,put stock 235/15's on it,it will make a huge difference...big tires and high ratio gears dont go well together..a diesel loves to run at low RPM,but overgearing it will reduce power significantly..My K20 has 245/75/16's,(at least 31" tall)-and I THINK it has 4.10's(might be 3.42's,never had the cover off to check the ratio yet)..mines pretty doggy on the street too,but no worse than my 305 in my 2wd C10 .. :crazy:
     
  6. Pookster

    Pookster 1/2 ton status

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    Do what everone else says- change all the filters (including fuel filter). A good oil change helps too. Be sure to give your truck regular oil changes! Very important on the 6.2's.

    Also, if you have time, check your pump timing- it could be off slightly and screwing things up.

    how many miles does this engine have? It could also be the injectors are not spraying too well. Try a double dose of diesel kleen.
     
  7. general blaze

    general blaze 1/2 ton status

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    i just had the belts, fuel filter and oil changed. not too much differnce but i got the rears spinning in the dirt today. so i am happy with that. ya i think my gears a long as hell. i drove home to Orange County the other day and at 80 mph it barely seemed like it was running.. I need a gear swap. I am running a 35 in tire. what are the recomended gears to put in this bad boy and where do i get them. Also it has a stock intake setup on there. Can i just replace that with a tall boy air filter? i dont need all that stock stuff do i?
     
  8. diesel4me

    diesel4me 1 ton status Premium Member

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    smaller tires cheaper than gear swap...

    I'd put some smaller tires on it--like 31's or even stock 235/15's..it will make a world of difference!..and its cheaper than swapping axles out or regearing them..35's are pushing it for a 10 bolt half ton axle anyway,especially if you take it wheeling off road..your tranny will thank you too,especially if its a 700R4!.. :crazy:

    A bigger element air cleaner wont hurt--since diesels take in a huge amount of air,its important to keep a clean air filter in it..but never run without one,and make sure any other air cleaner seals properly to the intake.so dust wont get sucked in the motor..the stock filter is good enough,I'd not spend any money there..as suggested earlier,cleaning the injectors by running some cleaner in the fuel,and the injector pump timing is important to get decent power out of a 6.2..make sure the exhaust pipes are not kinked too--if it cant breathe,power will drop dramatically.. :crazy:
     
  9. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    I'd swap to 4.56's. Give you plenty of grunt off the line, and still allow for a really civilized cruise rpm on the freeway. It'd be turning at 1950 rpm at 65 with 4.56's and the 35's (assuming you have the 700R-4).

    Rene
     
  10. general blaze

    general blaze 1/2 ton status

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    smaller tires are not an option. if anything they will only get bigger.
     

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