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what kind of oil pump on 70k miles sbc

Discussion in 'The Hokey Ass Message Board' started by kscarguy, Jan 14, 2013.

  1. kscarguy
    Joined: Aug 22, 2007
    Posts: 1,579

    kscarguy
    Member

    I have the pan off my SBC (I dropped the chain bolt down the distributor hole with intake off). Since the pan is off, I wondered if I should change out the oil pump.

    The motor runs fine but when warm the pressure drops to 20 psi. It is a stock 350 crate motor with about 70k mile on it.

    High pressure, high volume, new stock or leave it alone and just put it back together?
     
  2. flthead
    Joined: Jan 13, 2013
    Posts: 43

    flthead
    BANNED
    from Midwest

    The pump is fine. Bearing clearance dictates oil pressure.
     
  3. Hotrodbuilderny
    Joined: Mar 20, 2009
    Posts: 1,646

    Hotrodbuilderny
    Member

    You could pull a rod and main cap and look at the bearings, if it were me I would put a new pump in, why not? You are there, get a melling Hi volume Hi pressure pump if you are going to do any beating on it, and have piece of mind.
     
  4. Dooley
    Joined: May 29, 2002
    Posts: 2,693

    Dooley
    Member
    from Buffalo NY

    i am putting a new pump in myself...melling 55A which is standard volume hgher pressure...
     

  5. R Pope
    Joined: Jan 23, 2006
    Posts: 3,309

    R Pope
    Member

    A high volume pump will make more pressure at lower RPM. A high pressure pump won't be any different than a stocker if the engine isn't holding the pressure anyway.
     
  6. BOBCRMAN
    Joined: Nov 10, 2005
    Posts: 846

    BOBCRMAN
    Member
    from Holly

    Best pump made for modern performance SBC's.

    The 55hv. is a waste of money, a band-aid and can cause drive gear and timing problems.
     
  7. Hotrodbuilderny
    Joined: Mar 20, 2009
    Posts: 1,646

    Hotrodbuilderny
    Member

    So you are saying Melling went to all that trouble to make a band aid pump?I have run them on performance motors for almost 40 years and have never had a timing or drive gear problem.They are only a band aid if you have a problem and ignore it.
     
  8. txturbo
    Joined: Oct 23, 2009
    Posts: 1,771

    txturbo
    Member

    I would just clean the pickup and leave the pump alone. You put a new HP pump in and might do more harm than good.
     
  9. rockfish
    Joined: Apr 11, 2001
    Posts: 445

    rockfish
    Member


    Gotta read better man. No one mentioned a gear drive except you. The previous post talks about the DRIVE GEAR. As in the one that drives the oil pump. Smart ass posts are only funny if they're relevant.
     
  10. Okay, I'll go hop in my dis-Lexus now. :rolleyes:
     
  11. rockfish
    Joined: Apr 11, 2001
    Posts: 445

    rockfish
    Member

    Just having some fun with ya Wadda :D
     
  12. Nope, nope, nope! You're right, I screwed up and read it wrong. I'm not above (or below) anybody. I don't mind owning up!

    All's good man! [​IMG]
     
  13. CutawayAl
    Joined: Aug 3, 2009
    Posts: 2,144

    CutawayAl
    Member
    from MI

    If a particular engine doesn't NEED a higher volume pimp, there are no befits to using one and several reasons not to. It takes work to pimp oil, even if the oil is just bypassing. A high volume pump does increase drive gear wear and so does higher oil pressure. Whether the increased gear wear is obvious again depends on the engine and on oil pressure.
     
  14. :eek: :eek: :eek: :D
     
  15. Leave it alone. Only 70k. 20lbs at idle? No problems. Put it back together.
     
  16. Jay Tyrrell
    Joined: Dec 9, 2007
    Posts: 1,631

    Jay Tyrrell
    Member

    That is what I am thinking here too.
    Jay
     
  17. Deuces
    Joined: Nov 3, 2009
    Posts: 19,601

    Deuces
    Member
    from Michigan

    Low performance big block pump will bolt on also... 60psi at startup.... 45-50 psi when warmed up...;)
    I also like the extra capacity oil filter for pickups on a car motor..
    Like the old AC PF-35's....
     
  18. kscarguy
    Joined: Aug 22, 2007
    Posts: 1,579

    kscarguy
    Member

    Anyone know if Melling ever got their quality issues (from around 2007), corrected? I read a lot of post that showed cracked pumps and broken bolts. From what I read, they had changed the casting and used cast bolts and both weakened the pumps.
     
  19. FANTASY FACTORY
    Joined: Mar 6, 2008
    Posts: 256

    FANTASY FACTORY
    Member

    Heres another .02 from the doing it for 40yrs + crowd, By virtue of its use, an oil pump will not wear out, unless youre running around with little to no oil.
    Tight engine = hi pressure needed
    loose engine = hi volume
    other wise a stock pump is all you need,
    I ran a destroked mopar 340 thru the traps at 9700 with a stock pump and a 10 qt pan for 5 years, changed bearings once, only because i didnt pay for them,
    then did the same thing with a 311 chevy. clean the strainer, and put a washer under the pressure relief, 20 psi at idle hot? sweet!!!
     
  20. Hotrodbuilderny
    Joined: Mar 20, 2009
    Posts: 1,646

    Hotrodbuilderny
    Member

    If you read my first reply I said if you are going to do any serious beating on it.As I have stated I have run them and never had a problem, I also have run stock pumps from Chevrolet and not had a problem,but it sure isn't going to hurt anything except a few horsepower to run one.
     
  21. kscarguy
    Joined: Aug 22, 2007
    Posts: 1,579

    kscarguy
    Member

    I talked to a technical rep at Melling..here is what I found out:

    They redesigned the SBC pump in 2004. They blamed the issues of "breaking of the casting" on people hammering in the pickup tube while the pumps were bolted to the engine...causing fracturing of the lightweight casting. They also blamed solid motor mounts for the issues.

    The stock M-55 pump is still the redesigned "lighter"casting.
    The High Pressure M-55A is the heavier "original" casting and comes with an extra spring to lower the pressure.
    All the Select 10550-10555 performance pumps are the heavier castings

    All said...after reading all the blogs and seeing pictures of broken pumps, I am leary of using any of their stuff. I think I will leave my oil pump alone....of course, it is a Melling 55 made before all the changes.
     

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