Core Shift
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Core shift is when the casting mold itself was
moved during the casting process. For cylinder heads it can be
troublesome as when you are porting heads, you are making the walls
thinner. Go too far and you will swim in the coolant passage.
Some have asked how do we know which heads we deal with have core
shift? The pictures below show it perfectly. Here we
have cut the first 80 degree angle for the valve job (before we port
the head). With the good head the cut is completely circular
to the port. The head with the core shift you can see the cut
doesn't go all the way around. Heads with core shift are
perfect for stock rebuilds as we will simply blend this into the
bowl. However you don't want to port these castings as one of
the walls is now thinner than it should be, and any further porting
might make it too thin.
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Good head
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Head with core shift
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| This is the worse core shift we have seen on a 4V head. |
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| Yes we can repair this too. |
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