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Piston Ring instal. Question

Discussion in 'The Hokey Ass Message Board' started by 30 Buford, Apr 4, 2009.

  1. 30 Buford
    Joined: Nov 4, 2007
    Posts: 390

    30 Buford
    ALLIANCE MEMBER

    Question ;I got a new set of Perfect Circle Rings for my 401 Buick and they are in three seperate sections of the box .The top rings are right side up with the punch mark facing up . The second set are in the box with the punch mark facing down. The question is ,witch way do the second set go on the piston ? With the dot up or down like they were placed in the box ? There are no instructions included. Thanks in advance ,BC
     
    Last edited: Apr 4, 2009
  2. i would think with the dots up , that's the way it is on a SBC. maybe someone else here knows for sure
     
  3. R Pope
    Joined: Jan 23, 2006
    Posts: 3,309

    R Pope
    Member

    Dots up, always.
     
  4. GOSFAST
    Joined: Jul 4, 2006
    Posts: 254

    GOSFAST
    Member

    Hi BC, the "dots" always go "up" on the pistons.

    1-The "top" ring will have it's "dot" up and either no chamfer/bevel on the inside OR it will have a chamfer/bevel on the inside and on the same side as the "dot"!

    2-The "second" ring will have the "dot" up and it will have the chamfer on the opposite side of the "dot".

    Easier said, the "dot" and chamfer both up, this is the top ring. The "dot" and chamfer opposite, this is the second ring!

    Thanks, Gary in N.Y.

    P.S. The idea behind the chamfers up and down is, on the top ring, chamfer up, the gas/pressure gets behind the ring and helps to "force" it against the wall, on the second ring, chamfer down, the pressure in the crankcase (below the piston) gets behind that ring and "scrapes" the oil off the walls! The second ring is NOT a true compression ring, it is more of an "oil-control" deal than compression related!
     

  5. 30 Buford
    Joined: Nov 4, 2007
    Posts: 390

    30 Buford
    ALLIANCE MEMBER

    Thanks Guys , It looks like the top and second sets are the same, the dot and chamfer are on the same side . They both have the same color mark on them. I wonder if that is why the second set was upside down with the chamfer and dot facing down as that would be correct for the chamfer to face. Maybe they substited a set of top rings for the second groove.?
    What do you think ?Thanks, BC
     
  6. MBog
    Joined: May 2, 2006
    Posts: 552

    MBog
    Member

    I ran into the exact same thing with a set of rings for a flathead. I think the rings were boxed wrong. GosFast is right, follow what he said. I just put the second ring with dot down and bevel down.
     
  7. 30 Buford
    Joined: Nov 4, 2007
    Posts: 390

    30 Buford
    ALLIANCE MEMBER

    Thanks MBog, that makes sense to me .
    And Thanks Go Fast for the explaination of the bevels.
    BC
     
  8. GOSFAST
    Joined: Jul 4, 2006
    Posts: 254

    GOSFAST
    Member

    Hi BC, your welcome on the info, but I would contact Mahle, they own the "Perfect Circle" division, and question them personally.

    Rings are not something you want to fool around with or experiment with, there will be much grief if it fails to work??

    The materials used in the second ring are often "different" than the top compression rings, along with the radial tension as well?

    Thanks, Gary in N.Y.

    P.S. It only takes a simple e-mail or phone conversation to sort it out! Just my opinion here!
     
  9. 30 Buford
    Joined: Nov 4, 2007
    Posts: 390

    30 Buford
    ALLIANCE MEMBER

    Thanks Gary ,I was hoping on assembling my bottom end today , but I'll wait till tommmorow and make some phone calls to be safe. I don't want to have to take it apart again for sure. I did some searching on thier site before posting ,I go back and find a phone #.
    Thanks again ,BC
     
  10. MBog
    Joined: May 2, 2006
    Posts: 552

    MBog
    Member

    I just phoned the Federal Mogul tech line 1-800-325-8886. They said the top and second ring are installed dot up & bevel up on my flathead. I asked what the reasoning was behind that and he said I would have to talk to the engineers on that one. When in doubt ask questions
     
  11. JohnEvans
    Joined: Apr 13, 2008
    Posts: 4,883

    JohnEvans
    Member
    from Phoenix AZ

    In some apps. 1st and 2nd compression rings are the same when plain iron type rings are used.
     

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