"Real Life Stories" - Spark plugs gone bad

[Seth]

After the parts and tools portion posts, I've noticed that many of us carry a spark plug or two in our aircraft.  I only do because that's what was in the gear of the previous owner of the first airplane I owed.  I noted many who commented on the two threads I created mentioned carrying an extra spark plug.  I've also read it makes sense to have one on board, and it does.

I do understandy why, however I have to ask:  Has anyone had to ever use their spare spark plug?  Has one of the plugs for no reason whatsoever just gone bad with no warning and you were not near or at your home base?

Just curious to hear "real life stories."

-Seth

[DXB]

I'm curious as well, as doing so also means carrying the torque wrench, the wrenches for the harness electrodes,  copper gaskets, and maybe some anti-seize. When I first got my plane, I resolved to do this because I fouled bottom plugs on two occasions so badly i couldn't clear it.  But since becoming meticulous about leaning for taxi, I've had no issues, and I've never gotten around to putting this stuff in the plane.

[Andy95W]

I think for me it's a superstition thing.  If you have it, you'll never need it.

[Seth]

10 hours ago, DXB said:

I'm curious as well, as doing so also means carrying the torque wrench, the wrenches for the harness electrodes,  copper gaskets, and maybe some anti-seize. When I first got my plane, I resolved to do this because I fouled bottom plugs on two occasions so badly i couldn't clear it.  But since becoming meticulous about leaning for taxi, I've had no issues, and I've never gotten around to putting this stuff in the plane.

I also lean aggressively on the ground and have never had a problem with my spark plugs in 8 years of Mooney ownership.  I have also replaced my spark plugs when my maintenance facility's recommendation.

 

-Seth

[M20F]

Similar to Dev I have had a bottom plug foul and pulled it out, cleaned, it and gone.  If I pull it out, clean it, and then drop it....well you see why the spare could be handy.  For the most part if the plane breaks there isn't a ton of things you can do to fix it unless you happen to have the part handy.  Spark plugs are a very small and light part so worth carrying around.  I will carry a spare tire/tube when I am traveling to the middle of nowhere as well, never had a need to use it but it becomes an option to fix a problem.

[KSMooniac]

 

I had a crappy <200 hr Champion massive plug die at an en route fuel stop several years ago.  No warning on the first leg.  I didn't carry spares because I took care of my plugs with regular cleaning, gapping, leaning on the ground, etc. so I thought I would catch failing plugs at maintenance intervals.  Nope! 

Fortunately my engine monitor showed exactly which plug it was versus having to troubleshoot generic engine roughness. And luckily a mechanic was nearby and graciously loaned me tools, then confirmed the plug was bad and sold me a new one. I was on my way in 30 minutes instead of being stranded.  If this happened 30 minutes later, he would have been gone and then I would have been stranded without my own spares/tools.

Another plug showed bad at annual and then I replaced all of them with Tempest Fines and recommend them highly.

Sidebar, after years of denying their plugs quality had declined, Champion has now copied the Tempest design in an attempt to make a good plug again.  There are still lots of the old design out in the inventory, so I still recommend buying Tempest since they've been making great products.

Edited March 8, 2016 by KSMooniac

[N201MKTurbo]

In 5000 hours of Mooney ownership, I can think of three times I had a spark plug fail that I could not clear or clean onto functionality while away from home. I never had one with me, but I was always able to buy one from the local mechanic, or clean one from his bucket of used plugs.

[N201MKTurbo]

Funny story, I think the statutes of limitations has run out on this one...

I was at the Duluth airport and needed a spark plug. The mechanic was not there and the people at the front desk didn't know anything about airplane parts. They said the mechanic was a very crabby old guy and would throw a fit if someone was in his shop. I said I really needed the plug, so they took me to his shop and I found a new one. They wouldn't let me pay for it because they said that would involve telling the mechanic they went into his shop when he wasn't there.

[bradp]

I had one go bad mid flight.  This is once in about 400 hrs of Mooney ownership.   Engine monitor told me which plug based on an in flight mag check.   I now have another bad plug from the same batch of nicely clean and gapped plugs.  This is from the same batch of champions that I installed 2 years ago.  Two bad in less than 200 hrs.   I now carry an extra plug washer anti seize and torque wrench.  That is until I replace everything with fine wires.  Part of this is that most of my flying is on the weekend or during the night without easy access to mechanical help.  

[1964-M20E]

I have a wrench and several cleaned, tested and gaped spare plugs with me.  For installation on the ramp away from home I can use my calibrated torque arm and the never seize remaining on the threads in the cylinder. 

[DXB]

Seems like bad experiences with low time Champion plugs abound.  I just replaced all my 250 hr Champions, including 4 fine wires, with 8 massive Tempests.  They worked ok in the bomb tester but all were out of resistance spec with 6/8 reading open circuit.  I figured my new plugs should last at least 500hrs if well maintained.  Has anyone had Tempest plug failures that were early in their life?

[MyNameIsNobody]

1 hour ago, DXB said:

Seems like bad experiences with low time Champion plugs abound.  I just replaced all my 250 hr Champions, including 4 fine wires, with 8 massive Tempests.  They worked ok in the bomb tester but all were out of resistance spec with 6/8 reading open circuit.  I figured my new plugs should last at least 500hrs if well maintained.  Has anyone had Tempest plug failures that were early in their life?

My Tempest Massives  just keep on keep'n on...No worries.  Knocking on wood.  No need to tempt Mr. Fate.

[Oldguy]

24 minutes ago, MyNameIsNobody said:

My Tempest Massives  just keep on keep'n on...No worries.  Knocking on wood.  No need to tempt Mr. Fate.

+1 Replaced a mixture of Champion fine wires and massives with Tempest Massives and have not had a single problem. Never had one fail on me before switching, but did have several test bad at annual a couple of years ago. Decided to change them all at the same time.