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Please inform me if I am an idiot (hijacked to fuel pump tech)

Discussion in '1982-Present GM Diesel' started by 75-K5, Mar 5, 2007.

  1. 75-K5

    75-K5 3/4 ton status

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    I would like to describe and outline my current project below and gather opinions because I have been known to take bad advice, ass-u-me things, and just go off half-cocked in general. So please, take a moment to read through this post and let me know what I might be doing wrong.

    Current status is as follows:

    Bought a 6.2 out of a '91 Burb with 90-100k miles on it. Got the motor for $200 since it had blown a head gasket.

    Let engine sit for one year in backyard while busy doing other things.

    Source free 6.5 turbo setup, 90% complete.

    Finally, 2 weeks ago have the chance to start working on this engine. Here is what I have done:

    1. Took engine down to block and rotating assembly.

    2. Cleaned out rust on top of pistons (b/c of coolant sitting in cylinders for a while) using very lightly abrasive buffing tip on air grinder (NOT a die grinder, honing tool, or anything else that might take any considerable amount of material off). Did this with cylinder bank facing downward and rag with carb cleaner stuffed in the cylinder so as to not get any crud past or on the rings.

    3. Cleaned a ton, I mean a TON of sludge out of the engine. No grit or chunks, just extremely thick gunk, thicker than what I thought even a diesel should have.

    4. Get injectors tested, find out they are bad (probably from sitting). Once funds build up, going to buy 6.5L style replacements.

    5. Get heads checked, machine shop dude says they are not warped but one has hairline crack near a valve. They do pass pressure test so I say fuggit because I can't afford new heads right now.

    6. Reassemble engine with all new gaskets using Fel-Pro complete gasket set. (head gaskets, rear main seal, front crank seal, oil pan, valve cover, coolant, intake, exhaust, etc. etc. etc.). Shine up and spiffy clean all gasket surfaces before installing.

    7. New set of AC Delco 60Gs, installed with Anti-Seize.

    8. All bolts installed with automotive-grade (blue) Loc-Tite and torqued to specs listed in military service manual.

    9. New Melling oil pump and pickup screen.

    Does this sound like I have done everything reasonably right? What are opinions on this being able to handle a GM-3 turbo? I'm going to run it regardless, but just want opinions on whether it is going to grenade in 500 miles or not. I'm generally light-footed and easy on parts so that shouldn't be a huge issue.



    Bonus question: Can I run the gasser electronic in-tank TBI fuel pump in line with the stock lift pump? Will this help/hinder fuel pressure and flow?

    Thanks guys!
     
  2. savagek5diesel

    savagek5diesel 1/2 ton status

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    you're going to need to pull the heads back off if you didn't replace the head bolts with new ones. Those are torq to spec bolts from what i understand, and can only be torqued once.

    Your intank fuel pump question...... i think thats a no-go also. But i could be wrong. it's been gone over in the diesel forum a few times, you should be able to search it easily. Most guys install an electric pump inline on the frame near the tank to help prime the lines or for emergency use.

    I would be cautious about your coolant/oil temps if you didn't get a radiator from your donor motors truck. Although, a few guys have just blocked off their oil cooler lines at the block and havn't reported any problems yet. But that 6.5 will need alot bigger radiator than a 350ci.

    Other than that, you seem to have most of it in order. i'm sure the real guru's will chime in at any time. cool deal man. good luck.
     
  3. 75-K5

    75-K5 3/4 ton status

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    Oh yeah I forgot to mention I did get new Fel-Pro head bolts that came preloaded with blue grade Loc-Tite and what appears to be red RTV by the heads. :thumb:

    I do not yet have a radiator, but will probably try to source one from a 6.5 or BBC.

    Thanks for the reply!:D
     
  4. BKinzey

    BKinzey 1/2 ton status

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    fuel pick-up is different for a diesel and I don't think a gasser will work.
     
  5. imiceman44

    imiceman44 1 ton status

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    Gasser will work, ask Rene aka TrustyK5
    and the electric fuel pump will help the priming.
     
  6. 75-K5

    75-K5 3/4 ton status

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    Cool, I was hoping it would work because I will have the added filtration of the in-tank sock as well as the pumping assistance on steep inclines. :thumb:
     
  7. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    Well, about a year before I swapped the diesel in i swapped in a new fuel tank. That tank was from a diesel K5...so I have a correct diesel tank in my truck that had gas in it for a little while. The cleaning it out and flushing was easy enough, but I can't verify that a TBI tank is just fine because I didn't do that. I don't see a problem with it though...it's not like you're pumping bunker fuel through the pump.

    Rene
     
  8. imiceman44

    imiceman44 1 ton status

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    Oh well I thought you had a gas tank.
    But my 76 K5 still had the stock gas tank and they trasnplanted the perkins in there, and didn't modify anything.
    Still runs fine after 9 years.
    The TBI tank is better because it has baffles to keep the fuel pump from starving all the time.
     
  9. 75-K5

    75-K5 3/4 ton status

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    So I should be safe just keeping the in-tank pump wired to the ignition? I know there's the risk of getting in a wreck and catching on fire and the pump still pumping, etc. but that aside would this be acceptable? Much less wiring hassle if so.
     
  10. imiceman44

    imiceman44 1 ton status

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    That danger is the same wether it's a gas truck or diesel.
    Normally if the lines didn't break, the pump will shut off when pressurized.
    I don't know what kind of fail safe GM did for accidents but if something happens, have your family sue GM :D
     
  11. MaxPF

    MaxPF 1/2 ton status

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    The in-tank pump on TBI trucks is connected to a control relay which is in turn connected to a pressure switch in th eoil pressure sender. If the oil pressure drops below 5psi the relay cuts out and the pump stops. It would be wise to put the same sender on the diesel and wire it in the same. As a side benefit if you lose oil pressure for some reason it will save the engine from serious damage :wink1:
     
  12. imiceman44

    imiceman44 1 ton status

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    Thanks for the info.
    That means if the engine dies because of a ruptured line, or rolls over (no oil pressure), the fuel pump will shut off. :bow:
     
  13. MaxPF

    MaxPF 1/2 ton status

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    I hope the TBI pump works, since that is what I plan on using instead of the mechanical lift pump :laugh:
     
  14. 75-K5

    75-K5 3/4 ton status

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    Would there be any benefit in using both? TBI pressurizes line and mech. lift pump pulls from the available pressure? If not, then would you just block off the ports on the lift pump and bypass it altogether?
     
  15. MaxPF

    MaxPF 1/2 ton status

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    I am going to remove the lift pump and put a block off plate over the opening in the block. The plate will have a -12 AN fitting for turbo oil return to the pan :D
     
  16. 75-K5

    75-K5 3/4 ton status

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    Can you elaborate on that Max? I have a return line plumbed into the pan but not sure where the area where the lift pump is would come into the equation?
     
  17. MaxPF

    MaxPF 1/2 ton status

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    Well, since you already have a return it doesn't matter for your setup. I will be starting with a bone-stock 6.2, so I have to install an oil return somewhere. I can either put the return in the pan or in the block-off plate on the fuel pump boss. Actually, now that I think about it I will probably put it in the pan since it will be lower, and if I ever decided to go back to a mech. lift pump there wouldn't be a problem. So, forget I even mentioned it :ignore: I will probably just put a plain block off plate on the FP boss and call it good :thinking:
     
  18. k204dr

    k204dr 1/2 ton status

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    not sure how much pressure the tbi puts out, but you don't want more than 15lbs of pressure going to the injection pump.
     
  19. smalltruckbigcid

    smalltruckbigcid 1/2 ton status

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    And the reason for that pressure is because at any higher pressures the fuel will foam in the injection pump causing air lock problems. I think if the return on a 6.2 flowed a larger volume then a higher pressure at the injection pump wouldn't be a problem.
    George
     
  20. kennyw

    kennyw N9PHW Premium Member

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    The TBI pump is a higher pressure pump than the lift pump right? You may need to install a pressure regulator between the intank pump and the lift pump... or better yet, just remove the lift pump now and replace it with a block off plate and pressure regulator.
     

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