Engine Piston Bore Casting Broke Off. Will My 5.0 V8 Be Ok?

Discussion in 'Fox 5.0 Mustang Tech' started by waid302, Sep 12, 2013.


  1. waid302

    waid302 Member

    Joined:
    Sep 26, 2012
    Messages:
    51
    Likes Received:
    0
    Trophy Points:
    7
    I may have created a burr or a ridge during dis-assembly on bottom of #4 piston bore. I noticed my rotating assembly was tight in one area. I did honed the block with a ball hone. Since the engine was assembled, I tried to use a brass punch and tapped it lightly and it broke clean off! I guess the piston will get more oil lube now. The broken area is toward the cam shaft and not the trust side.

    I think it should be fine since the rings are way above and only around 1/2" of bottom of piston will see it.

    Should I be concerned ?

    Thanks

    Waid

    Attached Files:

    #1
  2. mikestang63

    mikestang63 Mustang Master

    Joined:
    Aug 28, 2012
    Messages:
    3,900
    Showcase:
    20
    Albums:
    1
    Likes Received:
    1,095
    Trophy Points:
    144
    Location:
    In the garage
    Should be fine as it is low enough in the bore, but if it were me, I'd probably sleeve it, as a crack could still develop. At a minimum you should knock down the sharp edges.
    #2
  3. 84Ttop

    84Ttop They make new pistons every day, so why worry? SN Certified Technician Mod Dude

    Joined:
    Jul 3, 2009
    Messages:
    3,235
    Likes Received:
    1,333
    Trophy Points:
    144
    Location:
    South Jersey
    At the very least file the edges of the chunk to smooth them. I would be interested to know the dimensions of the chunk, how far up the bore is it?
    #3
  4. RangerJoe

    RangerJoe Advanced Member

    Joined:
    Apr 27, 2010
    Messages:
    1,170
    Showcase:
    3
    Albums:
    1
    Likes Received:
    175
    Trophy Points:
    74
    Location:
    Georgia
    That just bothers me. Can't believe it broke like that. As already stated, i would be afraid the crack would spread.

    Joe
    #4
  5. waid302

    waid302 Member

    Joined:
    Sep 26, 2012
    Messages:
    51
    Likes Received:
    0
    Trophy Points:
    7
    Nice rounded off and smooth! Going to give it a shot since I actually managed to find this 96 block with only 75,000 miles. It had no piston bore ridge and have a TFS1 cam, GT40 heads with stiffer springs and T5 for it. Make that 6 T5's!!! This motor will see less than 1000 miles in a year in my 64 Falcon.
    I do have a spare 96 complete engine but it will require 0.030" over.
    Waid

    Attached Files:

    #5
  6. Mustang5L5

    Mustang5L5 Car used in adult film "Highway Gangbang-InDaButt" SN Certified Technician Founding Member

    Joined:
    Feb 19, 2001
    Messages:
    21,632
    Likes Received:
    307
    Trophy Points:
    124
    Location:
    Massachusetts
    Chips like that tend to concentrate stress. Whether that will become a problem is impossible to answer just on looks alone.
    #6
    Rick 91GT likes this.
  7. Rick 91GT

    Rick 91GT SN Certified Technician Site Sponsor

    Joined:
    Nov 30, 1999
    Messages:
    9,702
    Albums:
    1
    Likes Received:
    94
    Trophy Points:
    99
    Location:
    PA
    On a stock stroke motor it SHOULD be far enough from the rings but I'd assemble that bore first and check. If it is close that will cause issues...

    As long as you ground down past the crack and then debuted it shouldn't spread but that is very hard to tell on the internet.

    Sent from my XT907 using Tapatalk 2
    #7

Share This Page