Amigos,
I would have to agree with steel core plugs. My experience in Mfg. Engineering
at Ford and GM says steel is more durable and dimensionally stable than brass.
The corrosion concern is solved by the zinc plating on the plug. This is why we
don't use brass plugs for production engines. Steel is cheaper too. ; - ) And
we always apply anaerobic Loctite to the hole prior to pressing the plugs in
place.
And now for my pet peeve: The PURPOSE of the large core holes is not to protect
the engine in case the coolant freezes as is commonly believed. There are two
reasons for these holes: 1. To allow the sand cores to be supported during the
casting process. (They "float" in molten iron and shift around, therefore they
must be secured)
2. To provide exit ports for casting sand. After the casting is solidified,
and the resin binder in the sand core has burned up, the castings go through a
"shakeout" line where pneumatic hammers pound the *bleep* out of them and the
sand pours out the holes. Without these holes they could never get all the core
sand out and our radiators would be very unhappy. Not to mention heater cores.
BTW, in the majority of cases when the engine freezes, the "freeze plugs" don't
pop out anyway.
Just my $0.02.
Karl Payne
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