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My oil pressure drops over 4500 rpm...any ideas?

Discussion in 'The Hokey Ass Message Board' started by Baumi, Oct 12, 2012.

  1. Shaggy
    Joined: Mar 6, 2003
    Posts: 5,208

    from Sultan, WA

    That's just what i was going to add to the suggestions, not nessicerly falling off, but mabey too high
  2. outlaw256
    Joined: Jun 26, 2008
    Posts: 2,023


    im no pro but ive probably built 30-40 sbc. ive built some high dollar racing engines and some bad street engines.and ive used melling 55hv for everyone.ive used them with 7qt pans and even stock pans and ive never had any problem with them. ive never lost any bearings a crank or anything else due to thier use and every engine ive built has seen 7500 or more rpm.and a few for extended times.back in 77 or 78 racing head service out of memphis, where i lived close to is the one who told me to use them.i quess if they told me ,they should know atleast more than i one of my engines that ive kept up with that i built back in 83 is still going strong with only rings and bearings replaced at 57,000 more miles and that thing is beat on hard.the last 2 racing engines i built are still going strong. i think i built those at work back in 03. and again only have been freshened up.sorry guys but i cantb see one being sucked dry because of a hv long as the oil has a unrestricted return and the right amount of oil used that should do it.
  3. Kustom292
    Joined: Dec 21, 2008
    Posts: 217

    from Winnipeg

    A former boss had a similar problem with his bbc 69 impala covetable drag car. He found that the pickup tube was slightly bent up and at high rpm it would drop pressure as it was sucking up air with the oil. He unfortunately found this after the engine became a boat anchor. Too bad as it was a true 69 396 block.
  4. Country Gent
    Joined: Feb 22, 2010
    Posts: 562

    Country Gent

    I always thought good about Frams till I experience a welcomed situation. OT 98 Dodge Durango, 318 V8. Was using Fram till I came across the same comments on the Dodge Forum. I had what I considered decent oil pressure at highway speed till I switched to a Mopar filter and gained about 7lbs more pressure. Not for sure, but I believe Wix does the Mopar filters. My 2 cents:D
  5. Country Gent
    Joined: Feb 22, 2010
    Posts: 562

    Country Gent

    Man did you luck out. If that pickup would have come loose at the pump, you would have had TOAST for a engine.:eek:
  6. afaulk
    Joined: Jul 20, 2011
    Posts: 1,191


    What impressed me was the fact that you still had 40+ psi, after the pressure dropped. That is definitely what saved the day. My initial thought was that maybe clearances were growing when hot. Untold thousands of these engines have lost their pickup tubes and become boat anchors. I have rarely seen any problems with oil pan evacuation and that was with extended periods of operation above 7,000 rpm. With my blown alky car I run 11 quarts of Kendall Nitro 70 and a quart of Lucas. Now there's some oil pressure, 150+ cold, 75 hot, at idle. I'm glad you found the problem before it killed your engine.
  7. Baumi
    Joined: Jan 28, 2003
    Posts: 2,623


    Yes, I'm glad too! And I'm sure that keeping my oil level at maximum helped a lot to save the bearings!
  8. Was watching a small block Chevy loose oil pressure on a pull, so the engine builder put a lexan (1/4") valley cover on the engine to see what was happening. I literally watched the push rods disappear under oil, the oil was not getting back to the pan fast enough. Ended up putting some external drain lines back to the pan which corrected the problem.
  9. tricky steve
    Joined: Aug 4, 2008
    Posts: 380

    tricky steve
    from fenton,mo.

    one of two reasons.
    pick up tube fell off. or
    oil pump driveshaft too short.
    that's it.
  10. ironpile
    Joined: Jul 3, 2005
    Posts: 915


    Your oil pump pickup may be too close to the bottom of the pan.May be other problem as well.:confused:
  11. You guys really should read past the first two or three posts before commenting. ;):)
  12. Country Gent
    Joined: Feb 22, 2010
    Posts: 562

    Country Gent

    That's for sure!!!
  13. Diavolo
    Joined: Apr 1, 2009
    Posts: 813


    Thanks for getting back to us and letting us know what happened.

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