Tempest fine wire - issues

[xcrmckenna]

Last summer I managed to foul my fine wire Tempests after a maintenance test flight. Didn’t notice it at the time but heading home at altitude it started missing running 25 degrees LOP. When I got home I pulled the plugs and couldn’t believe they were firing at all.




I cleaned them up but the plane still ran rough LOP. Sent the data into Savvy and they pointed to a mag issue.

Last week during annual we pulled the mag and sent it in for an inspection, Kelly found both coils cracked and the block was bad.

I don’t know bad that is in mag talk but My Tempests kept firing through all of it. Four of my plugs had 220 hrs on them and the other four had 175 hrs. All electrodes were there and appeared in good shape. I hope I never have an electrode break off but I know I won’t run anything but Tempest Fine Wires in my plane.


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[bdash]

I had a Tempest fine wire plug lose its center electrode a couple of weeks ago. I initially noticed it only as higher than normal EGT on one cylinder during cruise, but a mag check once on the ground showed the engine running incredibly rough on the right magneto. That narrowed things down. I had a mechanic pull the spark plug in question and we were shocked to discover the center electrode missing. We replaced the plug with a Champion fine wire plug because that's what they had available.

Interesting to hear that this seems to be a somewhat common failure mode for the Tempest fine wire spark plugs.

[Andy95W]

It seems like the long-nosed Tempest "BY" plug might be the best of both worlds.  They have the robustness of the old massive plugs but the long nose does a lot to prevent fouling.  I'm not ready to go back to Champion plugs (at this point I have trust issues with them), so Tempest it is, for me!

[Bob_Belville]

I wonder how much, if any, of the missing electrodes incidents have been at least partially due to mechanics treating fine wires the way they do massives. E.g., these plugs are not supposed to be subjected to aggressive bead blasting. I suspect cleaning and gaping plugs is a task that gets delegated...  We're dealing with lingerie here not union suits. 

[Yetti]

2 hours ago, Bob_Belville said:

I wonder how much, if any, of the missing electrodes incidents have been at least partially due to mechanics treating fine wires the way they do massives. E.g., these plugs are not supposed to be subjected to aggressive bead blasting. I suspect cleaning and gaping plugs is a task that gets delegated...  We're dealing with lingerie here not union suits. 

In my case none.    They were installed and then failed.   No dropping no cleaning.

The report back from Tempest is there was a subcontractor that had issues welding the center electrode in the plug.

Edited April 5, 2019 by Yetti

[xcrmckenna]

In my case none.    They were installed and then failed.   No dropping no cleaning.
The report back from Tempest is there was a subcontractor that had issues welding the center electrode in the plug.

Did they say all issues were resolved?


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[Yetti]

2 hours ago, xcrmckenna said:

Did they say all issues were resolved?


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My understanding is they insourced the welding of electrodes.

[Jim Peace]

8 hours ago, Yetti said:

The report back from Tempest is there was a subcontractor that had issues welding the center electrode in the plug.

They told me that today...They made it up to me kindly though, I have a nice package coming my way..great customer support, Garmin can learn a lot from these people

[MinneMooney]

On 4/5/2019 at 11:27 AM, Andy95W said:

It seems like the long-nosed Tempest "BY" plug might be the best of both worlds.  They have the robustness of the old massive plugs but the long nose does a lot to prevent fouling.  I'm not ready to go back to Champion plugs (at this point I have trust issues with them), so Tempest it is, for me!

Andy, have you been running these for long? I was thinking about switching to them too if I can get a deal at EAA.

[Andy95W]

No, I'm not.  I have fine wires in my bottoms and regular Tempest massives in the tops (to save money- I'm pretty cheap).  At the time, I didn't realize these were available.

I did an Annual inspection on a neighbor's 172 who had the BY plugs and I was favorably impressed by how clean they were.  That was when I decided to switch to those when/if it came time to replace a plug.

Since then I've read here on Mooneyspace some people's reviews.  They seem impressed by them.

[Yetti]

I am running BY Champions on the bottom.   Helps with the #4 oily cylinder.   I went with Tempest massives on the top.

[ragedracer1977]

Well, my turn.  Lost the center electrode after only 24 hours of operation.  

Borescope didn't see any damage, nor the electrode. 

[jetdriven]

When were these plugs made 

[ragedracer1977]

3 minutes ago, jetdriven said:

When were these plugs made 

I'm not sure.  Is there a date code? I bought them from aircraft spruce in mid January

[ragedracer1977]

[carusoam]

Apparently everybody gets to spend time in the barrel...

Very fast detail posting, Brice!

Need any details/contacts to go with that?

Let us know what happens next...

Best regards,

-a-

[ragedracer1977]

4 minutes ago, carusoam said:

Apparently everybody gets to spend time in the barrel...

Very fast detail posting, Brice!

Need any details/contacts to go with that?

Let us know what happens next...

Best regards,

-a-

Looks like the best email is in this thread.  Interesting thing is, I noticed purely by chance.  I flew yesterday.  Engine was smooth, all temps normal, mag check perfect.  The fine wires are all on my surefly magneto.  I wonder if the surefly has enough energy to bridge the gap of the missing electrode??

i always do a post flight mag check, so unless it happened in the 15 seconds between the mag check and engine shut down.... 

[carusoam]

8 minutes ago, ragedracer1977 said:

Looks like the best email is in this thread.  Interesting thing is, I noticed purely by chance.  I flew yesterday.  Engine was smooth, all temps normal, mag check perfect.  The fine wires are all on my surefly magneto.  I wonder if the surefly has enough energy to bridge the gap of the missing electrode??

i always do a post flight mag check, so unless it happened in the 15 seconds between the mag check and engine shut down.... 

Quite possible, the energy of the sure fly is covering for the open gap.   
 

Expect when contacting the good people at Tempest, they will probably replace your faulty part...

If you can look for the missing piece, it probably went towards the muffler already...

Best regards,

-a-

[Marauder]

Looks like the best email is in this thread.  Interesting thing is, I noticed purely by chance.  I flew yesterday.  Engine was smooth, all temps normal, mag check perfect.  The fine wires are all on my surefly magneto.  I wonder if the surefly has enough energy to bridge the gap of the missing electrode??
i always do a post flight mag check, so unless it happened in the 15 seconds between the mag check and engine shut down.... 

Had the same failure yesterday. Momentary rough running. I think the mag was bridging the gap but I did see a lower EGT, not higher as you might expect running on one spark plug.

When placed in a spark plug test box, it did not fire.




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[Chessieretriever]

I understand the challenges associated with QC in manufacturing but have to say that purely from a statistical perspective (and as a turbo engine user) I am a little alarmed at the  frequency of "missing center electrode" reports. My recommendation to the nice and customer friendly folks at Tempest is to start treating this as a "statistical run" (read "emergency") and dedicate engineering resources to determine the actual root cause of it (and then change the process to eliminate it). It does not matter who has the problem (contractor or "in house") if the failure is inherent in the process used to manufacture the part (such process may not even have the capability to produce a part with the proper QC standard desired which I would assume should require a standard of "x" failures per million parts produced rather than something several orders of magnitude lower). If a center electrode goes through a turbo it will do damage regardless of how "lucky" someone might get. I hope Tempest can update this group on progress once they get on top of this to allow those of us who use fine wire plugs (by choice or SME recomendation or some other reason etc.) to regain the confidence in the product that it is capable of.

[ragedracer1977]

12 minutes ago, Chessieretriever said:

I understand the challenges associated with QC in manufacturing but have to say that purely from a statistical perspective (and as a turbo engine user) I am a little alarmed at the  frequency of "missing center electrode" reports. My recommendation to the nice and customer friendly folks at Tempest is to start treating this as a "statistical run" (read "emergency") and dedicate engineering resources to determine the actual root cause of it (and then change the process to eliminate it). It does not matter who has the problem (contractor or "in house") if the failure is inherent in the process used to manufacture the part (such process may not even have the capability to produce a part with the proper QC standard desired which I would assume should require a standard of "x" failures per million parts produced rather than something several orders of magnitude lower). If a center electrode goes through a turbo it will do damage regardless of how "lucky" someone might get. I hope Tempest can update this group on progress once they get on top of this to allow those of us who use fine wire plugs (by choice or SME recomendation or some other reason etc.) to regain the confidence in the product that it is capable of.

Yeah, this is seeming a little out of the ordinary for failure rate.

[MikeOH]

Replaced all my worn out plugs about a year ago with the same massives; was tempted to try the fine wires but I wasn't having any issues with fouling, so I just went with what was, and still is, working.

Looks like a good decision

[carusoam]

From my fuzzy memory we have at least a half dozen different people reporting the missing center electrode challenge...

And it has been going on for an extended period of time now...

I don’t recall anyone finding the missing part in the cylinder...

Finding it is a tough challenge... it may be hiding on top of a ring(?)

Sending a metal piece towards a turbocharger is just Bad on many levels...

Unfortunately, I only have fuzzy memories to use, and can’t pull out who had what failure when...

But, if Tempest stops by, I can help run the search function for them...

As usual, I sent a message to their customer service, including a link here...

Best regards,

-a-

[jetdriven]

It happened to me as well. I found a missing center electrode at annual. It had probably flown 20hr like this.  It even flow it LOP and to tell you the truth I didn’t really notice it. I even did a LOP mag check on the last flight.  The Bendix 1200 mag coils are like the D4LN dual mag coils,....  big.  The plug was firing.  

[Yetti]

The report from Tempest was electrode welding was outsourced.  They have since moved welding in house