Wow. It has been an intense owner-assisted maintenance day at our flying club for me. I learned how to do more of the steps of spark plug maintenance from nice but harried mechanics, we were short people everywhere today.
The only plug cleaning I've done til today is revving up the airplane at runup and running it lean and hot for a minute to remove plug fouling from flooding the engine!
This aviation blogger Andy
has a relevant post on airplane spark plugs here: http://www.theandyzone.com/flight/2006_03_01_archive.html
Anyway, here at a broad level (I may write up the detailed steps for myself at some point, though of course I am not a mechanic), are some of the things we do w/ the Skylane:
Remove all 6 plugs; need 2 wrenches, one to hold the small bolt, one to turn the large; also need a plug socket wrench to totally remove them (even though I CAN do w/ my fingers), cuz this special wrench will "catch" the plug. Once you drop a plug IT IS GARBAGE - the ceramic could well've shattered inside.
Put the 6 plugs in the labelled metal "basket" for each. (We CAN replace plug 2 top w/ plug 2 bottom, and vice versa, but canNOT move cleaned plugs to a NEW slot, hence the keeping them straight).
Take the basket into the hangar, and, first, clean them all w/ the vibrator.
Not sure if Andy's "cleaning machine" that sounded like a grinder is the same as the Champion thing we use with the two vibrating rods, but it could be. (Interestingly, a Cessna Pilots org. board has some people recommending AGAINST these machines, saying they could be too rough on the plugs. Hmm. I am WAY TOO MUCH a newbie to have an opinion yet!)
Ah, per SkyGeek (http://www.skygeek.com/sppltoeq.html),
the thing IS simply called a vibrator cleaner. So, run them all through that to get the worst crud off.
THEN, go to the "Spark Plug Cleaner and Tester" (must say I like Champion's easy descriptive names for tools!!), and....
Put each plug into the cleaning socket, push the red button to squirt special grade silica sand at the plug, whilst carefully twiddling the plug in a small circle, then keep twiddling while pushing the black button to blow air at the plug.
(If you are me today you find out the sand is low, so you have to find someone to help you find the sand, and it turns out its in a little Champion sealed bag, NOT in a huge canvas tote as you expected.)
Then, do NOT move to the TEST side of the Cleaner and Tester yet!! VERY important! I did NOT realize this at first...was not shown that step. The guys assume I've worked in a garage or hangar I think, which is nice, but WAY WRONG! Today was like BEING IN A FOREIGN LAND for me - MANY of the words I did not understand, AND thus could not look for the "X" which "should be right there next to Y." Riiight.
NEXT, you MUST use "the air gun with the red and black levers." Riiight. Turns out to be a nozzle/trigger thing that goes on an air hose; the mechanic found it, then used it. Anyway, we must use this to BETTER BLOW OFF the sand from the cleaner on each plug BEFORE testing it.
BUT, you still canNOT get to the TESTING side of the cleaner/tester yet!
Now, you must "Gap the Plugs." My husband explained this briefly to me last month (when I done the graphite painting and reinstalling of already cleaned plugs) from his youth of working on cars with uncles, but I did not really get it totally, til today...now I kind of get it.
What you are doing is testing the teeny air gap the spark has to jump between the "tongue" on each side of these RHB38E plugs and the core of same. You want uniformity as much as possible. We would like our plugs to be sparking on both sides.
To TEST, and tweak, the gaps, you first measure 'em with a "gap gauge" (Skygeek has these too, on the same page as above: http://www.skygeek.com/sppltoeq.html
; we have the little retractable kind. Our Skylane wants gaps between 0.016 and 0.017; luckily the gap gauge has a wire of 0.015 width and one of 0.019 width on one of the sides, so you want the 19 NOT to fit, and the 15 to fit loosely, with a bit of feel on each side, not too loose.
BUT OF COURSE FIRST THE GAP GAUGE IS NOWHERE TO BE FOUND! And I canNOT help LOOK FOR IT, cuz I have NO IDEA what it looks like!! (You might have gathered this was all super frustrating to me!! Being so uninformed. But at least now I AM more informed!).
So, me and the next guy w/ his plane's plugs (he's not used the Cleaner/Tester much, but HAS gapped plugs alot, so we help each other out) FINALLY find the gap gauge in the tool carrier where other spark plug stuff is. Duh!
THEN, we have to find the "Gap Setting Tool" (again, see the Skygeek page) to clamp onto one of the benches and to CAREFULLY use to screw down the awl-like point to push in any tongues that are far enough out to let a 0.019 wire fit in the gap. This PETRIFIES me for some reason I still don't quite understand - I am SUPER AFRAID of screwing this up! I get guidance from a bunch of different mechanics and seasoned pilots, finally one guy (thanks MB!!!) shows me how to put the 0.015 wire into the gap after the plug is seated in the setting tool, and then CAREFULLY screw down the awl/rod just a bit, and then test moving the 0.015 in and out. This is still hard for me, and I think I totally wrecked a plug that was already only sparking on one side...but then I DROPPED this plug anyway, so it was TOAST.
But finally I ALSO FIX another plug that was sparking only on one side and it now sparks on TWO in the Tester, hallelujah!!!
So I ended up going back and forth between the bench w/ the setting tool and the tester side of the cleaner/tester a number of times. THEN there was no replacement plug for the one I dropped, so we had to have our parts guy go buy some more. THEN another one would not spark AT ALL for me, so I had to use one of the extra new ones, and so on.
This took me AT LEAST TWO HOURS, I swear, and even caused a few tears, not to mention sweat and grime (no blood at least!)
But now that I come to type it up, I feel a bit of sneaking pride I LEARNED ALL OF THIS today at the hangar!!
HOPEFULLY R. and I will actually get to fly the plane tomorrow (when I will be ACUTELY aware of the sparkplugs!!!)