Clean tempest fine wire plugs

[Fritz1]

Took tempest fine wire plugs out during 25h oil change, minimal lead accumulation, engine runs smoother than with Champion massives, tad lower TIT, four out of six bottom plugs have a little oil in the cavity, what is the best way to clean these, to my best understanding you are not supposed to sand blast them with grit because that eats away the iridium coating quickly, so clean firing end with gunk carb cleaner? brake cleaner? or Hoppe gun cleaner? or what else?

[A64Pilot]

I ran fine wires for years on two different aircraft

All I did was every oil change I’d take them out and using a fine dental pick remove any fouling. I never blasted them with anything and never used any chemicals.

I’ve also used a very fine awl (ice pick) just be careful to not pry against the insulator if you use an awl

I have heard you can use Hoppe’s to soak and it will soften the fouling, but I never needed to

I would never blast them even with walnut shells I just don’t think that’s needed

[Greg Ellis]

I saw an A&P clean the spark plugs with 100LL once.  They came out pretty clean.

[Fritz1]

yep, thank you, will stay away from blasting, removed minor lead fouling with dental pick and oily residue with mineral spirits

[Fly Boomer]

1 hour ago, Greg Ellis said:

I saw an A&P clean the spark plugs with 100LL once.  They came out pretty clean.

There may be other issues, but that certainly sounds safe enough for the plugs.

[Mufflerbearing]

You could replace the bottom plugs with the tops and run it.  That'll clean them up.  Fine wires are amazing.

[Fritz1]

yes, did regular rotation after cleaning with pick and mineral spirits, they really do run better, think my TIT dropped 10 dF

[LANCECASPER]

1 hour ago, Fritz1 said:

yes, did regular rotation after cleaning with pick and mineral spirits, they really do run better, think my TIT dropped 10 dF

I've used fine wire on the M20R, M20M and M20TN. I liked them in all three applications, but I saw the biggest difference in smoothness with the fine wire plugs on the M20M. Every Bravo should be using these.

[Rmnpilot]

13 minutes ago, LANCECASPER said:

I've used fine wire on the M20R, M20M and M20TN. I liked them in all three applications, but I saw the biggest difference in smoothness with the fine wire plugs on the M20M. Every Bravo should be using these.

After I swapped my massives for tempest fine wires, my bravo starts better, idles better/lower (down to 570 rpm) and simply runs better.      

[0TreeLemur]

A question: I've got the Tempest fine wire plugs out of our IO-360 for cleaning.  Doing the resistance check, I notice some tarnish down in the contact well.  Anybody have a good method for cleaning that? 

[0TreeLemur]

Well, thinking about it, I cut scotchbrite into 1/4" strips, and worked it around in the bottom of the contact well with a small flat-bladed screwdriver.   Three times per plug seemed to do the trick.  Measured resistance of all eight plugs as 1200-1300 ohms.  That's a solution.   Before cleaning the varnish off the contact surface, I couldn't get a reliable resistance measurement.

[mhrivnak]

Luckily Tempest wrote down what they think: https://tempestplus.com/wp-content/uploads/2019/01/Sparkplug-Cleaning-The-Right-Way-081412.pdf

As for blasting...

"Fine wire spark plugs normally don’t need
much cleaning. However, if you do need to
get the lead out don’t pry against the
electrodes or insulators. If you blast the
spark plug, use only high grade, new,
spark plug abrasive. Use the lowest
pressure possible and blast for only a
second or two."

[A64Pilot]

Ever tried to blast something at the “lowest pressure possible” for a max of 2 sec?

Nothing is going to happen, I could do that to my finger, because what PSI is “lowest possible pressure”?

By not giving a pressure they really didn’t tell you anything

I never had a need, but then my engines didn’t burn excessive oil, and I cleaned and rotated them at each oil change.