Topic: Engine bore


joe b    -- 10-01-2014 @ 6:21 PM
  I have a '46 engine that has been bored 40 over. The cylinder walls show some scoring. What is the maximum safe diameter that it can be bored? What downside to further boring this engine?


kubes40    -- 10-01-2014 @ 7:25 PM
  .080" is no problem at all - no "downside" to that. Bigger bore than that and you may run in to a thin casting.
When I must go past .060" (rarely) I do a bell test after each .010" pass.


joe b    -- 10-02-2014 @ 6:28 AM
  Thanks Kube. What I needed to know.


TomO    -- 10-02-2014 @ 6:48 AM
  .060 is the largest size pistons and rings supplied by Ford back in the day.

Tom


cliftford    -- 10-02-2014 @ 3:58 PM
  Back in the day the hot rodders would bore these blocks as far as 3 3/8" to get more cu. ins. Sometimes they would get one with a thin cylimder wall suppoesdly caused by the core shifting during casting, and break through. The best bet is to bore just far enough to clean up all cyinders As kubes 40 said, 60 to 80 over should be no problem.


supereal    -- 10-14-2014 @ 11:57 AM
  You can order pistons and ring from Mahle for non standard oversize bores. Due to some core shift during casting, it isn't unusual to find sand holes when you go above .060 Have the bores checked before you begin. This week, a customer brought in a block to be bored and honed. The bores were like funnels, and someone had gone overboard with a ridge reamer, which will leave a problem at the top of the bores. We suggested that he look for another block, as this one is "iffy".


supereal    -- 10-14-2014 @ 12:06 PM
  I'm not sure that attachment will open since we changed to Windows 7. I'll try again.


joe b    -- 10-14-2014 @ 12:15 PM
  Thanks Super. They both opened for me.


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