Briggs 12.5 hp ring end gap

Discussion in 'Mechanic and Repair' started by tomjan357, May 24, 2004.

  1. tomjan357

    tomjan357 LawnSite Member
    Posts: 2

    I am rebuilding a Briggs 12.5 hp vertical shaft engine. I am having a hard time establishig what the end gap on the rings should be. I am using .010 over rings and trimming them to the correct gap. They overlap about .004 to .005 before trimming.
    The rings I bought didn't have any papers in the box to identify the rings. I memory serves the top ring has the inside champher the second ring has a step on the bottom. Any help will be appreciated. Thanks, Tom
  2. martinw

    martinw LawnSite Member
    Posts: 23

    I'd have to look at a manual (at my shop location) on what ring goes where, but what concerns me is it sounds like you are using 10 over rings on a standard bore. You will probably run into problems with the oil control ring cutting it down and it "sealing" like it should. Also (I am probably opening a can of worms here but...) hou can you shave (lets say) .08 off of a ring that is designed to be a perfect circle a(t the size it was made at) and expect it to rebend and form a perfect circle again (at a smaller size)?????.

    My sugestions would be to either get the block bored to the ring size, buy the correct sized rings, or (if you are worried because your block is a little out of round) buy (std size) chrome rings (they are designed to "cut" and reform to a block that is up to .005 out of round.

    Why "rig up and make due" on a machine that you are makking money with, spend a little do it right and make alot.

    Just my $.o2 worth
  3. tomjan357

    tomjan357 LawnSite Member
    Posts: 2

    Thanks for the reply. I have honed the cylinder to almost .010 over. I could hone it the rest of the way out instead of trimming the rings. I still don't know the correct end gap so I don't know when to quit honing the bore. You raised a good point about the rings maintaining a perfect circle in the proper bore size, I had overlooked that fact, Thanks. As for the .005 over chrome rings, I was told not to use them in a cast iron bore. Thanks for the reply. Tom

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