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Oil leak 1948 fl

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  • Oil leak 1948 fl

    I am putting a 1948 FL together for a customer. It came to me in baskets. I have had the bike running on a gas bag, though not effectively. Two issues: Carburetor and Oil leaks. I have asked for help through another post with the M74 Linkert. This post addresses the oil leaks.

    I installed an aftermarket oil pump. Stock-type, not S&S or another. It is a new one. The bike also had/has an old style oil filter housing that attaches directly to the oil tank. That filter housing leaks badly and I have not been able to stop that leak. When running, the bike leaks from the front of the front rocker box and the rear of the rear rocker box, in addition to leaking at the bottom of the oil filter canister attached to the housing. Oil also collects at the bottom of the rear pushrod tube, almost like it is being pushed up from a full cam cavity, though I do not know quite how that would happen.

    The 'How to Restore Your Harley-Davidson" book says due to over-oiling problems the 1948 OHV engines went through several mods. That portion of the book talks about the check valve being an issue. I took the oil pump check valve out and the pressure relief valve out and inspected them. The pressure relief valve spring is quite stout, but I have no way of knowing if that is the issue. Thinking that the oil filter may be causing restriction, I removed the oil filter housing and ran the bike with a "return' hose into the tank. The rocker boxes and rear tube still leaked.

    I am in the process of removing the heads to check both rocker boxes to be sure there are not any drain hole issues, or anything else that is obvious and causing a restriction.

    It is properly timed, as the photos show, so that should not be an issue.

    These are about the last two issues I need to resolve before putting the fuel tanks on and making it a functional unit, God willing. Both the carb and oil leak issues have been a challenge and I could certainly use and will appreciate any help any of you can offer.

    Thank you.

    Bob
    20190821_134400.jpg20190821_135257a.jpg20190821_135500.jpg20210129_175337.jpg .


  • #2
    Rocker box covers. Are you sure they are flat where they rest on the top of the heads. Type of gasket you using on the rocker covers?

    Are you using cork seals on the pushrods? How old are springs on the pushrod tubes?. Are the pushrod tubes original or aftermarket? Maybe inspect the bottom of that tube to be sure it is not split or damaged. Replace that pushrod tube with another from your stash to see if that solves the issue.

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    • #3
      Thank you, Panz4ever.

      A little background. Chasing the leaks, I have the front head off, the rear not off yet. Horseshoe tank, stock, as far as I know. Did not drain the tank. Came back to the bike after 2 days away, there was a puddle of oil in front under the cylinder; while hard to tell with oil, I'm guessing 1/2 a quart and still slowly coming out of the feed hole. It leaked out of the oil feed hole in the front cylinder. This bike does not have an external tappet screen. Coming from the tank, the oil would have had to get past the check ball in the oil pump, just sitting. The oil line you see in the photo is temporary. I am also chasing/trying to get it to stop, the external oil filter housing, which leaks very badly out of the bottom, and I was not sure it was not somehow causing a restriction. Oil did flow back to the tank, when the bike was running.

      In your opinion and knowledge, would a check valve ball, not seated, with the head ON be able to fill up the heads with oil, just sitting, over time? Since that is the feed, and even without an external tappet screen, it seems to me that the check ball would stop the oil from gravity feeding when the engine is not running and the breather gear timing would be the control of oil going to the heads. So, what happened may be diagnostic? The oil pump is an aftermarket (V-Twin) pump.

      To answer your questions:

      I'd say the front rocker box cover is not dead flat, on a dead flat granite surface, but almost and does not rock. With the James D ring gasket on and the pan on the gasket, it appears to be flat. When I take the gasket out, and just put the pan on, it does not fit fully down, all the way around, but I can push it down, one side to the other, so the felt on the inside of the pan and the studs for the rockers are not allowing it to drop down fully Without a gasket installed. Front D ring, not flat, does rock on the dead flat granite surface; when on with the gasket, though, it seems to push the pan down evenly around the head, though, that could be an illusion, since I do not have the screws in and torqued, at this time..

      Gaskets are from a James kit.

      Cork seals.

      Old tubes and springs, no way for me to know stock or after market, that I know about. This engine has been around a lot, I'd say and was a mess when it came to me, still put together. I have ordered new pushrod tubes and also have non-cork seals that I can use in place of the cork seals. The cork seals are hard to get to go into the pushrod tubes and the lifter blocks.
      20211029_121246.jpg20211029_121252.jpg

      Thank you for your help.

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