That is not a easy repair in aircraft cylinders, most times the heli-coil is damaged beyond the repair limits. so a case saver is installed, this requires special tools, which required machining a new hole, and installing a special bushing.
My opinion won't sway yours or Lycoming's, but I have found engine-oiled plugs hard to get out after they've been in there for too long in too much heat. Oil turns to a sticky varnish after a while and can make a plug harder to remove if the varnish gets hard enough. But that's just my opinion.Since Lycoming says anti-seize or engine oil, which engine oil do you experts think works best?
That should keep you busy for awhile.
If the cylinder head gets so hot that the copper anti-seize is over temped, that engine has bigger problems than a spark plug change. Copper anti-seize is good to 1800 °F
I suspect the plug was probably just barely inserted and maybe engaged by one thread. Very unlikely that a merely un-torqued but fully screwed in plug would unscrew itself with the ignition wire still attached. Try it. I have seen plugs that were never wrench tightened at all and nothing much happened
I prefer the onion layers description of knowledge. Each time you expand your knowledge to a larger ring, it takes more to expand it further, and you are aware of more of the gaps in your knowledge (the next ring)
The plug didn't unscrew itself. Read the post again. It took a helicoil to repair it because the aluminum threads were torn out by the plug as it was blown out. Overtorquing weakens the threads.
I never torqued my automobile spark plugs until I bought an airplane and bought a Snap-On torque wrench.
The plug was fully screwed into the head. It may have only been finger tight or it was wrench tight but not torqued. The Nissan KA24DE engine is a dual overhead cam engine. As such the plugs are inserted vertically into a long tunnel in the valve/cam cover. My automotive SOP is to hold the plug in a spark plug socket with foam insert on an extension, and screw finger tight, then wrench tighten. I may have forgotten to wrench tighten. After the blowout, the head threads had play. I took that as a result of the loose plug vibrating against the aluminum thread and wearing them away.
It's funny, some worry about a couple foot pounds of torque, when I'll wager that 90% of the torque wrenches never get calibrated.
or worry about the quality of the tools they use.
Yet there are those who are that anal retentive
Sometimes the margin between undertorqued and overtorqued is narrow. Too much torque and you crush the structure and/or overstress the fastener. Too little and the fastener will let the parts move relative to one another and cause damage. One of the bad places is the Cessna 180/185 and old 182 horizontal stab pivots under the stab's aft spar. Some mechanics think it's supposed to pivot on the bolt so they leave it a little loose. It's actually supposed to pivot on the bushing that the bolt is supposed to clamp between the structural bracketry. Leaving it loose lets the stab move the bolts and wallow out their holes in an area where there is no margin for any repair, so major, very expensive replacements result. Cessna has a torque spec right on the diagram in the manual.
I'm pretty sure that if you fly over a school for the handicapped children of personal injury attorneys your airplane will automatically go into a nose dive right into it.
That must be why the departure procedure for the airport where my mechanic is located says not to fly over the school just off the end of the runway. They must have heard that I was using sub-standard anti seize.
Oh yeah, and I don’t use trim for landings. And sometimes I even do straight in approaches to our privately operated grass Airpark.Like to live on the edge, don't you.
That's you,, not every one is that way.
Right. but you haven't said how much different it makes between the two types of anti-seize
Right. but you haven't said how much different it makes between the two types of anti-seize
Real mechanics want to know
If the spark plug is corroded in, there is some thing matter with your maintenance practices.
So, same mil-spec, should not be much torque difference.
Clearly you had the gasket on backwards. Amateur.
Like using the wrong anti-seize?
So how come nobody has complained about me just using the cheap aluminum Permatex anti seize yet? Can’t be worse for galvanic reaction than the copper (contains aluminum and copper, but less copper). I guess I am just so far off the deep end that it is a lost cause. I’ll let everyone know when my plugs all back out in flight.Like using the wrong anti-seize?
I was just looking at something else that stated never to use graphite pencils on aluminum due to galvanic corrosion. So that is interesting as it seems that would go against that what I had recently read.I suppose the graphite spark plug thread lubricant marketed by Tempest is a no no..
So looking at this galvanic chart, steel and aluminum are very close to each other, while copper and aluminum are much farther away, with graphite being at the extreme far end from aluminum. What am I missing here? Copper and aluminum together will result in aluminum corroding. Graphite and aluminum is the worst combination possible.
Probably missing that the stuff is in some sort of grease, so there is nothing to carry the ions/electrons to close the electrical circuit. There shouldn't be much water from combustion getting up there.
Sure, just responding to @Doug Reid who stated that it was somehow better to coat the aluminum in copper to prevent corrosion from steel when in fact the copper would promote more corrosion than the steel itself.
My plugs that I just replaced were so old that they were super rusted just above the threads. Like not just surface rust but solid pitting 1/16” deep all over. Serious material loss on the spark plug body. The threads? No rust.
Ok, so the copper won't corrode, the aluminum will. How does that help either the cylinder or your claim that copper works better? Please explain to me in more than one sentence why coating aluminum in copper would help prevent corrosion. We have already established that the anti seize is mainly protecting because of its oil-base. But you said that the copper would prevent corrosion - how?
