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


Much simpler way; fill the low part of the drill and tap with grease. The
chips will stick to it and come out with the drill or tap.

ALWAYS use a "never seize" on the plug threads,in aluminum. I stuck a plug
once and it broke at the gasket area. Wrecker engine time then.Just be
cautious tightening the plug and go on the lower side of the torque.

Dale Davies