Oil pressure: At a loss

Discussion in 'Small Block Tech' started by Sierraecho5, Sep 8, 2017.

  1. Sierraecho5

    Sierraecho5 Member

    Yes. They're there. I seem to be losing pressure more towards the bottom end.
     
  2. CJay

    CJay Supercar owner Staff Member

    Im confused, this is a fresh rebuild from a machine shop?
     
  3. Sierraecho5

    Sierraecho5 Member

    I'm really wanting to pull the crank and rods I'm going to under size the crank and use oversized bearings. I'm thinking that when the crank was polished it lost a little in the diameter. With it being 50 yrs old I imagine there was a little wear down that went unchecked. So I will mic everything myself. But I already found the wrong front cam bearing in the top end who knows what i'll find wrong in the bottom end.
     
  4. Sierraecho5

    Sierraecho5 Member

    Yes. I assembled the heads, valves, lifters, and rods. .I also just redid the top end cam bearings again when I realized there was no oil pressure, hoping not to have a bottom end oil issue.
     
  5. Jim Blackwood

    Jim Blackwood Well-Known Member

    You said you had the end clearance on the oil pump at stock specs.
    That may not be good enough. In most cases the end plate is not perfectly perpendicular to the gears, meaning that if it is at stock spec at the closest point it can have a larger gap on the other side. A fairly serious problem. I set the end clearance so the gears just barely drag (and of course carefully and LIGHTLY deburr the gear edges), that way I get the minimum possible working clearance. The gears will wear-in to the cover and the housing will expand as it heats up, giving even more end clearance. I've been getting very good results with this method.

    Jim
     
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  6. Sierraecho5

    Sierraecho5 Member

    Thanks Jim. I'm fairly sure it isn't the oil pump or timing cover. I have 2 covers. I have the OEM cover and the TA high pressure oil pump cover. I've tried different combinations of both covers and oil pump housings. I've done as much as I can think of to not pull this engine... But that is something to think about for minimizing gear end clearance. I'll consider that when I'm removing the old gasket material
     
  7. UNDERDOG350

    UNDERDOG350 350 Buick purestock racer

    Does your block have the oil feed holes going up toward the heads and rocker stands?
     
  8. Mark Demko

    Mark Demko Well-Known Member

    Ahaa!!
     
  9. Jim Blackwood

    Jim Blackwood Well-Known Member

    If you have it on the engine stand it's pretty easy to pressure test your oiling system with compressed air. That will tell you where the oil is coming out for sure.

    Sometimes blocks do have flaws. I had a 300 block with a hole in the suction galley.

    Jim
     
  10. Mark Demko

    Mark Demko Well-Known Member

    OOOOPS, That could be your issue, worn original cam bearings will hemmorage oil at the cam journals and most importantly starve the main and rod bearings
     
  11. Sierraecho5

    Sierraecho5 Member

    I got it figured out. The block was cracked at the lifter gallery on the passenger side. It was under the mains so hard to spot. I got a new engine in the car. (Well the original engine with upgrades) Jolene runs like a Champ...=D
     
  12. hwprouty

    hwprouty Platinum Level Contributor

    Nice! Glad things worked out.
     

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