Amen to this, the term freeze plugs is so misleading, though I still prefer
brass. I think the big question for the car makers is cost. I have seen only
three modes of plug failure, seepage, pop out, and rust out. Seepage shows up
right away (if a plug starts seeping years later its a rust issue which is
different) and is a fitment issue not a plug materials issue. Pop out is not
exactly plug materials related either. But rust out is completely materials
related and happens to all steel plugs, zinc plated or not. Besides the brass
plugs look much cooler. :-)
karl.payne@gm.com wrote:
>
> 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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