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Mystery grub screws?

  • WhiteTrash
    WhiteTrash
    7 months
    Inside this Shovelhead House of Horsepower case are 4 grub screws that, for all I can tell, seem to do all of nothing but come loose and dance around the engine case.
    Given that the OEM style bearing race grub screws are used I doubt they are for that.
    To be honest, I have not seen this before, anyone know the purpose of these grub screw?
    Grun screws..jpg
  • Hilly
    Hilly
    7 months
    I'm no shovel guru by any means but as far as I know there should only be 2 grub screws to hold the case bushing in coming in on an angle, perhaps, and I could be wrong, the bushing came loose in the past and someone has drilled and tapped some extra holes to try and prevent it from happening again, you got a parts book or workshop manual for that model to see if it sheds any light?
  • 408
    408
    7 months
    Would go along with that. FC might chime in when he gets home from the pub.
  • Far Canal
    Far Canal
    7 months
    What case are we looking at here?
    Shovels were built for many years.
    Burp
  • WhiteTrash
    WhiteTrash
    7 months
    Quoting Far Canal on 25 Apr 2024 09:36 AMedited: 25 Apr 2024 09:37 AM

    What case are we looking at here?

    Shovels were built for many years.
    Burp

    Its a House of Horsepower nose cone shovel case.
    Year is unknown... in fact finding any info on these after market cases has been hard.
  • B0nes
    B0nes
    7 months
    Was checking out a shovelhead years ago with HH cases, not sure if true but was told that you could tell the year by the serial number. Last two digits of the serial number was the year made. Maybe hard to find much on these cases as I think the guy that produced them has long shuffled of to greener pastures.
  • WhiteTrash
    WhiteTrash
    7 months
    Quoting B0nes on 25 Apr 2024 10:23 PM

    Was checking out a shovelhead years ago with HH cases, not sure if true but was told that you could tell the year by the serial number. Last two digits of the serial number was the year made. Maybe hard to find much on these cases as I think the guy that produced them has long shuffled of to greener pastures.

    I have heard that too .... but I doubt my case was made in 1933.

  • Hilly
    Hilly
    7 months
    Old but not that old lol, I'm wondering if the bush is walking under pressure a little and that's making the grub screws come loose, any sign of fretting around the bush/case interface?
  • Hilly
    Hilly
    7 months
    It's probably tight right now while it's cold but when it's hot you have two different materials with different expansion stats so the tolerance has to be right from the get go and if it has come loose in its long past history the bore might be a tad larger than it should be, all conjecture here but that's my fitter and turners take on just a pic.
  • WhiteTrash
    WhiteTrash
    7 months
    I just found a right hand case for sale on ebay, with a nice picture of the inside.
    Interestingly it only has the 4 grub screw, no OEM style grub screws.
    grubs screws.png
  • Hilly
    Hilly
    7 months
    I guess that's how they did theirs, when you cast your own you can do what you want, made a bit of a mess, did it lock up?
  • Hoodeng
    Hoodeng
    6 months
    House of Horsepower used the 4 screws for some insurance holding the cast in insert in place, the left case was the same. They very rarely came loose, no more than stock cases.

    The early OEM cases that had two angled  #10 screws were not to locate the insert but to locate the race in the insert.These also ever had to work, if these screws were holding the race in place the cases were already in trouble. Harley deleted these race locator screws in around 78 with no problems.
    They also deleted the cast in insert without any issues in the ninety's, and ran the Timken and pinion races directly into the cases.

    Years ago when the idea of removing, welding up and machining a new Timken or case race insert that had come loose we used to drill and tap near through the cases 1/4" unc intersecting the case and the insert and inject solvent till it came out clean, then use the grub screws to inject 680 loctite till that oozed out of the clearances, lock it up and give it time to set, this was a successful repair a number of times.
    More often than not a un-cinched left insert would let engine oil migrate into the primary first before actually making a noise, this was evident to owners that had replaced sprocket shaft seals and found that did not correct an over fill primary issue.
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