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. 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 ?



    Attached Files:

  2. 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.
  3. 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?
  4. That just bothers me. Can't believe it broke like that. As already stated, i would be afraid the crack would spread.

  5. 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.

    Attached Files:

  6. Chips like that tend to concentrate stress. Whether that will become a problem is impossible to answer just on looks alone.
    Rick 91GT likes this.
  7. 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.

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