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Thread: 1973 Shovelhead Oil Pump Isuues Help ???

  1. #11
    Join Date
    Apr 2010
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    1,115

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    It still could be new stuff loose in old lifter blocks or adjusted wrong..i'm done

  2. #12
    Join Date
    Jun 2019
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    Pennsylvania
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    Thanks Duffy, really appreciate the info. After seeing what work this clown did on my bike, I'm sure there's plenty that's wrong ! I think I found a new TRUE Harley mechanic, gonna have him take a look. Tim

  3. #13
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    Aug 2004
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    Beautiful Northern New Mexico
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    Tim, 6 page PDF in your email.
    Robbie
    Robbie Knight Amca #2736

  4. #14
    Join Date
    Jun 2001
    Location
    Central Illinois, USA
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    4,308

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    I didn't know hydraulics need pressure.

    ....Cotten
    Last edited by T. Cotten; 06-28-2019 at 07:23 PM.
    AMCA #776
    Dumpster Diver's Motto: Seek,... and Ye Shall Find!

  5. #15
    Join Date
    Nov 2018
    Location
    Reno NV
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    200

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    Quote Originally Posted by Twister the fitter View Post
    More puzzling pump finds ! Removed both CHECK VALVE PLUG and RELIEF VALVE PLUG and SPRINGS only to find CHECK BALLS in BOTH ports (???). I realize a Check Ball should be in the port closest to the engine, but my service manual shows a #26400-54 Oil Pump Valve in the taller port, NOT a Check Ball, is this correct ??? Confused !!! Another reason I'm looking for that #647 Service Bulletin. Could this be why I not getting enough oil press. to operate the hydraulic lifters, or is this the "so called" mid 1973 design change ? I was able to identify my pump from Rubone's pic as being the Early 1973 version, if this helps ? Thanks so much fella's, she's still sittin idle . . . . ha ha
    The Check ball closest to the engine is a non return valve to stop the oil tank draining into the bottom end when the motor is not running. It has a low pressure spring sitting on top of it.
    The other valve is a pressure relief valve. It should have a short "Piston" with a heavier spring on top of it. (Length varies by model) Pt no 26400-54. The piston moves up under pressure, (varies according to the spring rate) and opens up a port into the cam chest that relieves oil from the pump. This piston must slide freely. Even though the engine only sees a low oil pressure, the chamber between the pump gears and the relief valve carries a higher pressure than the engine.
    If you have a ball in here, you will probably never get any oil to your tappets. All your oil is probably bypassing the ball and relieving into the cam chest.

  6. #16
    Join Date
    Jun 2019
    Location
    Pennsylvania
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    Hey Cotten, according to the clown (mechanic) that just did all that work on it, tearing out, replacing, and putting all back in, claims that's what's causing my troubles ??? Poor oil pressure he says, or clogged passages to the tappets. I don't know how he figures it's low oil pressure, when I questioned him about testing pump with a gauge, he said no, I didn't put one on to check it, seems to me he's just guessing ??? That's when he said to ride it until winter when he can tear into it further. Duffy makes a good point, when he says to check for worn or loose tappet blocks, tappets, etc. You'd think this guy would've checked all that first, before putting in those new parts and all the work involved, right ? Tim

  7. #17
    Join Date
    Jun 2019
    Location
    Pennsylvania
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    Thanks for the info Aumick10, I'm on a "mission" now !!!

  8. #18
    Join Date
    Nov 2018
    Location
    Reno NV
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    There is also a screen before the tappets, just by the rear right barrel stud. Should look the same as the two plugs on the oil pump. Fix the relief valve, clean the screen then you should be able to put in hydraulic tappets.
    Make sure you have the correct spring in the relief valve part.
    Good luck.

  9. #19
    Join Date
    Jun 2019
    Location
    Pennsylvania
    Posts
    25

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    Aumick10, Have all new OEM parts ordered. I did check the screen, it was ok, but I'm not sure what springs were used, that's why I ordered OEM. Thanks for this info, it sure helps those of us in need, when nobody else seems to have any ideas or answers ! We need to get all of you AMCA guys together, say in the middle of the country, build a huge shop completely outfitted, so that those of us can come and get everything fixed that's needed ! Thanks Again, Tim in PA

  10. #20
    Join Date
    Nov 2018
    Location
    Reno NV
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    200

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    I hope you don't mean work for free, unless there is free beer involved.

    I am surprised you were able to get the plunger as a OEM.
    There are different springs available to change the oil pressure, but I am not sure they change anything. Stick with OEM when available, no point in reinventing the wheel.
    I just put fuel in my 29 JD to start it after maybe 50 years. rebuilt carby pissed fuel out everywhere, so i am dealing with that now.
    Cheers

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