The other day I went to change my oil and plugs, but one of the
plugs had seized and getting it out really did a number on the
threads in the housing and cam out with several of the deepest
threads caked with aluminum.

I went and got a tap and helicoil kit...

I re-tapped the threads and the new spark plug seems now to fit
fine and snug up OK, but I am a little worried about all the
damage that must have been done. I am now trying to decide
which is the lesser of two evils. Leaving the threads as is if
the spark plug can get torqued to spec, VS. installing the heli
coil and possibly getting aluminum shavings into the combustion
chamber. I would stuff it with grease soaked rags, but there is
always a concern. Up sizing the hole for the heli coil will
make a LOT of shavings.

My though is that if the threads can tolerate the proper torque,
then they should be good to go.

Opinions?

Does anyone know the proper torque on the spark plugs?
--
David Leonard

Turbo Rotary RV-6 N4VY
http://N4VY.RotaryRoster.net
http://RotaryRoster.net

http://www.ngksparkplugs.com/techinfo/spark_plugs/installation.asp

The engine should survive a few aluminum shavings. They should melt
the first time it fires. No guaranty :)

Use a grease soaked string.

I would pump (with a grease gun) the top dead chamber full of
Vaseline before you started drilling and tapping. Then rotate it
around to the exhaust port and dig the Vaseline with the chips out
from there.
Then flush it with auto TX oil.

Paul Lamar

I'm sending spark plug torquing instructions recently posted by Lynn
Hanover. Hope it is of some help.

Mark


Now tighten the new plug into a scrap housing, or your wife's Honda
to 14 foot pounds and then back out. This to flatten the sealing
washer.
Then wipe on just a hint of Nickel anti-seize on the threads. Nothing
within 1/4" of the tip. Practice torqueing to 10 pounds with
extension sticking through between your middle and ring fingers.
Torque a plug into a scrap housing to 9 pounds, then turn it by hand
to what you think is 10 pounds. Then check the plug with the wrench
set at 11 pounds. The plug should turn a bit to get to 11 pounds.
Get a feel for 10 pounds using your wrist only. 10 pounds with lube
is plenty. After a few installations the anti-seize will have been
spread all the way to the inside end of the plug hole. Great heat
conductivity. Plugs will never lock up in the hole. Threads will
last as long as the housing.

Always use a torque wrench. But if none is available you can do the
ring
finger trick and get 10 pounds every time. Only you tighten plugs,
not your ham fisted brother in law.



Lyn Hannover

For a plug torque chart, go to;
www.championsparkpluds.com/charglossary.asp
<http://www.championsparkpluds.com/charglossary.asp>

Plugs can also be tightened properly without a torque wrench. For
new plugs or
with a new gasket I think it is 1/8 turn from finger tight. If
reusing the
gasket, 1/16 turn from finger tight. You need to be sure the plug is
contacting the gasket surface of the housing at finger tight. Never
seize on
the threads. If it wants to turn more than prescribed without
snugging up, it
was not on the gasket surface. Taper seat is 1/16 turn from finger
tight.

Dale Davies


First, DO NOT USE A HELICOIL! Sorry to shout but helicoiling spark plugs
has always been a bad thing to do. The helicoil partially insulates the
plug and that can require you to use a colder plug.
The best insert you can use for the plug hole repair is called a "Time
Sert". Made by the Time fastener Company they are the best inserts you
can buy, period. Search Time Sert on the web to find their site. The
plug inserts are steel but they are copper plated to insure proper heat
transfer. Look them up you will be glad you did. I won't use anything
else now.
Bill Jepson

Still have your RV10 Kit Bill?

Paul Lamar

Hi Bill,
It's funny that you feel so strongly about Time Sert. I did know of
them from my search, but most people seemed to weakly recommend the
heli-coil. As far as heat transfer, it does not make much sense to me
that a alum-copper-steel-copper-alum interface should necessarily do any
better than alum-steel-alum... no matter though, because it is easy to
start using cooler plugs if needed.

I liked the idea of a coil as a means of taking up any slop and
preventing any breakage. Lastly, Todd Archer told me about some
certified aircraft engine that comes new with helicoils.

That being said, it is not too late for me to switch. I taped out the
hole today and feel confident that I got out all themetal chips big
enough to do any harm. But when inserting the coil it mis-threaded and
had to be removed, which destroyed it. So now I still have my choice.

At the auto parts store there was an insert that appeared to be black
anodized alloy, or the heli-coil (both labeled as generic inserts) does
that sound like the Time Sert? Do you think the threads are going to be
the same for the two?

--  David Leonard

Turbo Rotary RV-6 N4VY
http://N4VY.RotaryRoster.net
http://RotaryRoster.net



The Time Sert is unique, and patented. The Time Sert is solid, but
before you think clunky and big, they devised machinery that "Times" the
threads so the peaks and valleys follow each other. David, you are in
luck because the Time Sert can use the same thread as the helicoil.
Check with Time Fastener about that. GO TO THEIR SITE AND. CONTACT THEM
BEFORE USING ANY COILED SPRIAL INSERT! I can't state it any more
strongly use a genuine Time Sert and you will be happy with it. The TS
uses a partial thread at the bottom of the insert. You use a roll tap to
complete the thread and swage the insert in place.
Bill Jepson