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New Oil pump. reccomendations?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Ddragggon, Dec 21, 2001.

  1. Ddragggon

    Ddragggon 1/2 ton status

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    my 73 K20 needs a new timing chain, and the craptacular oil pump puts all of 8 PSI of pressure out at idle. I figgure while I have the pan, and engine face off to do the chain, I may as well get the pump replaced. couple of questons tho:

    -what flow rate does a stock pump flow at? (GPM)
    -what flow rate should I look for?
    -would I be allright if I just put a 454 oil pump in, and called it good? (its a 350, ) or would I have too much pressure?

    I plan to pull the main bearing caps and check for any signs of bluing, but I probably won't replace them, unless its serious like a heart attack. other then having an apparently bad timing chain, and no oil pressure at idle, the engine runs great.

    on a side note, if I did need to replace the main bearings, would I have to tear the whole engine down? if so, I think I'll just swap in the spare 454, and be good to go... only reason I'm holding off on that is I'd have to upgrade the entire driveline of the thing, and I might be trading this thing for a 65 suburban.

    -Rich

    My truck isn't ugly, you have a skewed sense of beauty

    <font color=blue>2007 Ford XLS++ intrepid Ram Superduty 7000 R-type's suck</font color=blue>
     
  2. michaelm

    michaelm 1/2 ton status

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    low pressure is a sign of wear, bearing clearance somewhere has loosen up
    run a stock pump or risk sucking the sump dry
    american engines have an oil reservoir that is ridiculously small.
    my wifes Geo metro takes about 4l(over an american gallon) of oil for 1l of engine displacement
    a 14l(855ci) truck diesel takes 9 or 10 american gallons(38l) of oil
     
  3. Ddragggon

    Ddragggon 1/2 ton status

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    I'm thinking about putting a larger pan under the engine too... I already run a 2 quart oil filter, and figgure if I can get a 6-8 quart pan under it, it'll help out more too. its bad enough that the 5.7 (350 ) only runs 5 quarts of oil, but its something worse that the 7.4 L ( 454) also only runs 5 quarts. the other thing I suspect is that someone rebuilt this engine as a high HP racing engine... its got a really high HP cam in it that hates idling below 800, and runs best advanced by 16 degrees, and when they built the engine, they could have used looser bearings to allow it to spin up faster or something.

    at worst, all this engine needs to do is last long enough for me to get money together to throw a beefy tranny behind my 454.

    -Rich

    My truck isn't ugly, you have a skewed sense of beauty

    <font color=blue>2007 Ford XLS++ intrepid Ram Superduty 7000 R-type's suck</font color=blue>
     
  4. slider

    slider 1/2 ton status

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    That is low oil pressure, usually a sign of very worn bearings, esp cam bearings. My 350 had about that oil pressure when I tore it down and the thing was toast, The cam bearings were almost gone, I think it would be rebuild time for that motor, has the pressure just dropped like in the past few weeks or what? If it has just had a sudden drop it could be a pressure relief spring that has gotten stuck open not allowing pressure to build, I would just pull the pan off and give the bottom end a good look over before I bought parts, It might be a waste of time to try to save a dieing bottom end without changing the cam bearings. Check the numbers on the pump and try to run them somehow to see if your pump is high volume or not. Good luck dude, hopefully it is a easy fix.
     

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