On Jul 18, 10:37 am, "Lloyd E. Sponenburgh"
wrote:
"jor" wrote in messagenews:2007071806510216807-jor@jorcom...

I would worry LESS about the chips and metal pieces falling inside the
cylinder and MORE about how I would remove the hardened piece of easy-out
that breaks off in the head.......................

They SHOULD be called "hole-pluggers"..........

Man, you can say that again! I've used "easy"-outs a bunch of times and
most turned into, as you say, hole pluggers. Then you really have a
problem: How do you drill out that hardenen steel? Interestingly enough,
apparently I never learn the lesson. Each time I have a broken bolt, I
look at my collection of easy-outs and think, maybe this time...

'Never hear of a "left-hand drill"? For many extraction jobs, that's the
ticket. If sized appropriately, it doesn't tend to expand the item in the
hole, rather, it "grips" from the top.

LLoyd


I agree, the left hand drill is best way to start working on many
broken fasteners. If you are going to have to drill it anyway, you
might as well use the left hand drill and give it a chance to come out
before you do anything else.

I've had fairly good luck with easy-outs. You have to know when and
how to use them, though. If a screw snapped because it bottomed out
in the hole or was cross-threaded or corroded into place, the easy-out
is not as likely to be effective as it is if the screw failed due to
shearing or tension. The most common mistake people make with easy-
outs is using too large a size. The thinner the walls of the broken
screw are, the more likely the easy-out is to expand them and lock the
threads. While the larger easy-out is of course stronger, it's better
to first try a smaller size that will not expand the screw. There are
some non-tapered screw removers with straight splines that work
without expanding the screw.

It's hard to imagine why a spark plug would break in the middle of the
threads - usually the undercut at the shoulder is the weak area.

Two points in this thread got my attention:

1. Never-Seize. I've heard at least once that there are good reasons
NOT to use it on spark plug threads, but I can't remember what they
were. Yes or no?

2. Better to remove plugs hot or cold? Posters in this thread have
it both ways.

John Martin

"John Martin" wrote in message
ps.com...

1. Never-Seize. I've heard at least once that there are good
reasons
NOT to use it on spark plug threads, but I can't remember what they
were. Yes or no?

Autolite says not to use anti-seize becasue it can contaminat the
spark plug insulator and short out the plug (anti-seize includes
metallic elements). NKG says it is not necessary with their plugs
becasue of the plug construction and they recommend against its use
becasue the lubricating properties of the anti-seize can lead to
improper torquing of the plugs.

2. Better to remove plugs hot or cold? Posters in this thread have
it both ways.

In an aluminum head you should remove the plugs when the head is cold.

Ed

C. E. White wrote:
"John Martin" wrote in message
ps.com...


1. Never-Seize. I've heard at least once that there are good
reasons
NOT to use it on spark plug threads, but I can't remember what they
were. Yes or no?


Autolite says not to use anti-seize becasue it can contaminat the
spark plug insulator and short out the plug (anti-seize includes
metallic elements). NKG says it is not necessary with their plugs
becasue of the plug construction and they recommend against its use
becasue the lubricating properties of the anti-seize can lead to
improper torquing of the plugs.


2. Better to remove plugs hot or cold? Posters in this thread have
it both ways.


In an aluminum head you should remove the plugs when the head is cold.

Ed




We've all learned that a hole in a block of metal gets larger when the
metal expands and the coefficient of thermal expansion for aluminum is
about twice that of steel, so I'd expect the diametrical fit to get
looser when the head gets warm.

But I'm willing to learn something new every day, so why do you say you
should remove the plugs when the head is cold? (Maybe it has something
to do with the relative change in thread pitches at different
temperatures? Naw...)

Jeff

--
Jeffry Wisnia
(W1BSV + Brass Rat '57 EE)
The speed of light is 1.8*10^12 furlongs per fortnight.

"Jeff Wisnia" wrote in message
...
C. E. White wrote:
"John Martin" wrote in message
ps.com...


1. Never-Seize. I've heard at least once that there are good
reasons
NOT to use it on spark plug threads, but I can't remember what they
were. Yes or no?


Autolite says not to use anti-seize becasue it can contaminat the
spark plug insulator and short out the plug (anti-seize includes
metallic elements). NKG says it is not necessary with their plugs
becasue of the plug construction and they recommend against its use
becasue the lubricating properties of the anti-seize can lead to
improper torquing of the plugs.


2. Better to remove plugs hot or cold? Posters in this thread
have
it both ways.


In an aluminum head you should remove the plugs when the head is
cold.

Ed


We've all learned that a hole in a block of metal gets larger when
the metal expands and the coefficient of thermal expansion for
aluminum is about twice that of steel, so I'd expect the diametrical
fit to get looser when the head gets warm.

But I'm willing to learn something new every day, so why do you say
you should remove the plugs when the head is cold? (Maybe it has
something to do with the relative change in thread pitches at
different temperatures? Naw...)

Jeff

I am actually repeating the recommendations from shop manuals and plug
manufacturers (remove plugs when cold). The question is, what has
expanded more when hot, the heads (making the hole larger) or the
plugs, making the fit tighter. Aluminum expands at a higher rate than
steel, but it also cools faster, particularly on a water cooled engine
where the water in the head should limit the peak temperature of the
aluminum head to a lower value than the steel sleeve of the spark
plugs. As things cool, I suspect the aluminum head will cool much
faster. So it may be that the fit is actually tighter when the head is
hot, not looser as you are suggesting. But even if it is isn't, what
happens when you screw the new cold new plug into the hot (or at least
warm) aluminum head? The thread fit will be looser than designed and
this might make the torque applied incorrect, or make the thread
easier to strip. The original plugs and head were cold when assembled,
so it only makes sense to me that the same is true for the
replacements.

Ed

"C. E. White" wrote in message
news:469fb213$1@kcnews01...

"Jeff Wisnia" wrote in message
...
C. E. White wrote:
"John Martin" wrote in message
ps.com...


1. Never-Seize. I've heard at least once that there are good reasons
NOT to use it on spark plug threads, but I can't remember what they
were. Yes or no?


Autolite says not to use anti-seize becasue it can contaminat the spark
plug insulator and short out the plug (anti-seize includes metallic
elements). NKG says it is not necessary with their plugs becasue of the
plug construction and they recommend against its use becasue the
lubricating properties of the anti-seize can lead to improper torquing
of the plugs.


2. Better to remove plugs hot or cold? Posters in this thread have
it both ways.


In an aluminum head you should remove the plugs when the head is cold.

Ed


We've all learned that a hole in a block of metal gets larger when the
metal expands and the coefficient of thermal expansion for aluminum is
about twice that of steel, so I'd expect the diametrical fit to get
looser when the head gets warm.

But I'm willing to learn something new every day, so why do you say you
should remove the plugs when the head is cold? (Maybe it has something to
do with the relative change in thread pitches at different temperatures?
Naw...)

Jeff

I am actually repeating the recommendations from shop manuals and plug
manufacturers (remove plugs when cold). The question is, what has expanded
more when hot, the heads (making the hole larger) or the plugs, making the
fit tighter. Aluminum expands at a higher rate than steel, but it also
cools faster, particularly on a water cooled engine where the water in the
head should limit the peak temperature of the aluminum head to a lower
value than the steel sleeve of the spark plugs. As things cool, I suspect
the aluminum head will cool much faster. So it may be that the fit is
actually tighter when the head is hot, not looser as you are suggesting.
But even if it is isn't, what happens when you screw the new cold new plug
into the hot (or at least warm) aluminum head? The thread fit will be
looser than designed and this might make the torque applied incorrect, or
make the thread easier to strip. The original plugs and head were cold
when assembled, so it only makes sense to me that the same is true for the
replacements.

Ed

I think the aluminum may be weaker and have a greater tendency to sieze or
gall when hot, but I am not sure of that.

Don Young

"C. E. White" (clip) Aluminum expands at a higher rate than steel, but it
also cools faster, particularly on a water cooled engine where the water in
the head should limit the peak temperature of the aluminum head to a lower
value than the steel sleeve of the spark plugs. As things cool, I suspect
the aluminum head will cool much faster. So it may be that the fit is
actually tighter when the head is hot, not looser as you are suggesting
(clip)
^^^^^^^^^^^^^^^^^
I think that "hot" refers to an engine at operating temperature. "Cold"
refers to an engine that is essentially at ambient temperature. The rate of
heating or cooling does not enter into the discussion. Since aluminum has a
higher coefficient of expansion, it will result in more clearance around the
threads on a hot engine.

But note that the head and plug expand and contract in a vertical direction
also. The head gets thicker when it is hot, more than the plug expands, so
the gasket is more compressed. That sounds like a plus to me.

"Leo Lichtman" wrote in message
...

"C. E. White" (clip) Aluminum expands at a higher rate than steel,
but it also cools faster, particularly on a water cooled engine
where the water in the head should limit the peak temperature of the
aluminum head to a lower value than the steel sleeve of the spark
plugs. As things cool, I suspect the aluminum head will cool much
faster. So it may be that the fit is actually tighter when the head
is hot, not looser as you are suggesting (clip)
^^^^^^^^^^^^^^^^^
I think that "hot" refers to an engine at operating temperature.
"Cold" refers to an engine that is essentially at ambient
temperature. The rate of heating or cooling does not enter into the
discussion. Since aluminum has a higher coefficient of expansion,
it will result in more clearance around the threads on a hot engine.

But note that the head and plug expand and contract in a vertical
direction also. The head gets thicker when it is hot, more than the
plug expands, so the gasket is more compressed. That sounds like a
plus to me.

When you are changing plugs you are not talking about an engine that
is "operating." You are somewhere between steady state operating
conditions and cold. If you try to change the plugs before the engine
is "cold," the temperature of the parts is changing constantly as you
work. Under operating conditions I am guessing the body of the plug is
much hotter than the surrounding metal of the cylinder head. Part of
the plug is actually down in the combustion chamber. There is
discontinuity between the plug and cylinder head, adding an impediment
to thermal transfer. The actual head has internal water passages, so
the maximum head material temperature is limited. When you turn the
engine off, the aluminum head cools much faster than the spark plug.
The effect on the forces needed to remove the plug is not clear to me,
but it is certainly changing as the engine cools. I just can't see how
it is better to change the plugs during this period of time (as the
engine cools) that waiting for it to reach ambient conditions.

Ed

"C. E. White" wrote in message news:469fb213$1@kcnews01...

"Jeff Wisnia" wrote in message ...
C. E. White wrote:
"John Martin" wrote in message ps.com...


1. Never-Seize. I've heard at least once that there are good reasons
NOT to use it on spark plug threads, but I can't remember what they
were. Yes or no?


Autolite says not to use anti-seize becasue it can contaminat the spark plug insulator and short out the plug (anti-seize
includes metallic elements). NKG says it is not necessary with their plugs becasue of the plug construction and they recommend
against its use becasue the lubricating properties of the anti-seize can lead to improper torquing of the plugs.


2. Better to remove plugs hot or cold? Posters in this thread have
it both ways.


In an aluminum head you should remove the plugs when the head is cold.

Ed


We've all learned that a hole in a block of metal gets larger when the metal expands and the coefficient of thermal expansion for
aluminum is about twice that of steel, so I'd expect the diametrical fit to get looser when the head gets warm.

But I'm willing to learn something new every day, so why do you say you should remove the plugs when the head is cold? (Maybe it
has something to do with the relative change in thread pitches at different temperatures? Naw...)

Jeff

I am actually repeating the recommendations from shop manuals and plug manufacturers (remove plugs when cold). The question is,
what has expanded more when hot, the heads (making the hole larger) or the plugs, making the fit tighter. Aluminum expands at a
higher rate than steel, but it also cools faster, particularly on a water cooled engine where the water in the head should limit
the peak temperature of the aluminum head to a lower value than the steel sleeve of the spark plugs. As things cool, I suspect the
aluminum head will cool much faster. So it may be that the fit is actually tighter when the head is hot, not looser as you are
suggesting. But even if it is isn't, what happens when you screw the new cold new plug into the hot (or at least warm) aluminum
head? The thread fit will be looser than designed and this might make the torque applied incorrect, or make the thread easier to
strip. The original plugs and head were cold when assembled, so it only makes sense to me that the same is true for the
replacements.

Ed


You let the engine cool down first so you don't get burned right.