Mechanical vs hydraulic valvetrain

Slant 6 Engines

  1. 66Dirtydart

    66Dirtydart Well-Known Member

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    I recently bought a 66 Dart with a 225 in it. The PO said the top end had been swapped to the newer hydraulic style lifters.

    Well, the lifters and pushrods were swapped however it's got a solid lifter cam in it. The top end is a total mess due to lack of lubrication I'm assuming.

    I'm trying to figure out what rockers and remaining valve train components I have. Can anyone show me the difference between a hydraulic and solid rocker arm? How would I tell which set I have? Mine have a hex adjuster above the pushrod which leads me to believe they're for a solid lifter, but I want to make sure it isn't put together incorrectly this time.

    Thank you!
     
    Last edited: Aug 28, 2019
  2. Plymouth 65

    Plymouth 65 Floorable Deplorable

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    The hex nut on the rocker means you have adjustable. 65'
     
  3. RustyRatRod

    RustyRatRod I was born on a Monday. Not last Monday. FABO Gold Member

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    If you have the adjustable rockers, then they have not been swapped for the hydraulic assembly. Hydraulic slant rockers are non adjustable and do not have the hex nuts. They also take ball and ball pushrods, rather than ball and cup like you must have. ARE YOU SURE it is a solid camshaft and has not been changed to a hydraulic? You cannot "just throw" a hydraulic camshaft in a slant without all the other needed parts, because they do not oil from the lifters. They oil from the head, into the rocker shaft through the rocker arms and finally into the lifters, I believe. I don't think any slant six was ever drilled for an oil through lifter galley that I know of. They oil from "the other side". So, that means if someone just threw a hydraulic camshaft in it, it has likely burned up some "stuff".
     
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    • Killer6

      Killer6 Well-Known Member

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      1) Define "The top end is a total mess",..???
      2) As stated, the oil starts at the top, nothing You do after that is going to make the "top" end a total mess.
      3) If somebody tried to toss the hydraulic lifters & cam in there w/o the hydro top end & rockers/pushrods,..the lifters will stay collapsed and would quiet-up if You ran the adjustments down I s'pose,...but it wouldn't run too well.
      4) You can't throw hydro pushrods on a set of mech./adj. rockers because they are ball&ball ended, not cup&ball as mechanicals are.
      5) howsabout some pics....????
       
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      • 66Dirtydart

        66Dirtydart Well-Known Member

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        Thanks for the replies, guys. I'll take some photos when I get home, but looking at photos of cams I don't believe my cam is hydraulic. I suppose I don't understand the oil system.
        I have hydraulic lifters as well as socketed pushrods. My rocker arms have the adjuster on them.
        I do have a photo of the rockers I believe, I'll upload it now from my phone. I'm at work, I can take a photo of the cam when I get home.

        When I said it's a mess, I meant I have mismatched parts and the valve train is covered in sludge and coked oil.

        20190825_142942.jpg

        20190825_142947.jpg
         
      • 66Dirtydart

        66Dirtydart Well-Known Member

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        I disassembled the short block last night but didn't get any of the lifters out of the block, I think they're mushroomed. I assumed they were hydraulic because of the previous owners claim and can't see them well from the top.
        I think they're solid, it makes sense because every other component in the valve train appears to be.

        Thank you for your responses, sorry for the ignorance. This is my first slant, I'm learning. It's crudded up from lack of maintenance.
         
      • RustyRatRod

        RustyRatRod I was born on a Monday. Not last Monday. FABO Gold Member

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        It's a learning process. No need to act like any stupid questions have been asked. They have not. It's all good. That's not very much sludge at all. I've seen them so bad that you cannot even SEE the rocker arms. You can clean that up by dumpin a can of SeaFoam in the crankcase and running it for an entire oil change. That will likely get it clean. SeaFoam is some good stuff.
         
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        • fishmens67

          fishmens67 Well-Known Member

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          I think the previous owner thought he was spicing the deal up. lol I don't think the top end has ever been apart.
          The slant looks like every old engine I've taken apart, Sludge and charcoal.
           
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          • Killer6

            Killer6 Well-Known Member

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            Many many times, (almost always), it's difficult to impossible to just pull the lifters out of an old engine because of varnish/cooked oil on the lifter body below the bore, spray some penetrant and work them. They make tools to grip and pull or use a small slide-hammer for this reason/purpose. Welcome to the forum, and as RRR said, no question is stupid for a relative newbie. Ask away! :thumbsup:
             
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