Tempest or Champion Fine wire Iridium?

[JoeSpeed]

My Platium enigne was delivered with Champion Fine wires. Anyone have a report on the Tempest (Autolite) Fine wires?

[testwest]

Just (a few hours ago) flew Tempest fine wires in my "other Mooney"...an Aerostar 601P, Lyc IO-540-S1A5 turbonormalized. So far so GREAT!

[thinwing]

I have about 50 hrs on a set of tempist(autolite) fine wires....no issues at all...kp couch

[jetdriven]

One thing we noticed is how much smoother it runs, especially at idle.  then flight testing it we noticed we can go to 90 LOP smoothly, instead of just peak with the old (worn out) massive electrode plugs.  So now we can run 20-50 LOP at 65% power and save 2 GPH.  They are Autolite plugs, which are now called Tempest.  

[knute]

I saw some earlier scuttlebutt that Autolite was building the fine wire plugs (or in the process of moving the production line) in Mexico, but for what it's worth the UREM38S Tempest plugs that just came UPS from Spruce are all proudly stamped "Made in USA" on the side of the barrel.  Interesting.  They do look shiny!

I'm looking forward to seeing how well they perform.

-Knute

'66M20E - N6066Q - KSQL (San Carlos, CA)

 

[testwest]

It would be interesting for Jetdriven to measure the resistance of the center conductor on the Champion plugs he replaced. With the old Champion massives, I also had poor idle and "plug fouling" problems after start that always made run-ups an adventure in roughness with recalcitrant plugs. This was in our Aerostar BTW.

After replacing all the plugs with Tempest fine-wires, my IA measured the resistance of the center conductor on the Champion massives that were removed from the left engine. Although the electrodes were not worn out, 11 of the 12 plugs had center electrode resistance well above the nominal value of 800-1200 ohms. A few were so high he remarked that it was amazing they fired at all. The problem is they "look ok" in terms of visual judgement of spark quality on the bomb tester.

We have a Seneca here locally that also found high center electrode resistance on the Champion plugs removed from his airplane. After replacement due to high resistance values (even though the plugs were serviceable according to all Champion criteria for return to service) the problems of fouling, lack of firing at altitude and so on went away.

I will have more data soon, but here is what I think is going on......carbon-pile/spring/screw resistor plugs (like Champion) do not hold their resistance stable over a long period of time. My hypothesis is that those plugs whose resistance has drifted high will tend not to wear out the electrodes (low spark energy does not transfer/erode as much metal, though I highly doubt the relationship of spark energy to metal erosion is a simple linear one....) and so remain in service, since there is no criterion for removal from service for high resistance. Yet.

I have a feeling Tempest knows this, because their fired-in resistor design is completely different. Their ads also allude to the drifting resistance issue for carbon-pile/spring/screw type plugs, so I believe they are aiming their marketing at a competitor's problem which is likely to become more well known.

[jetdriven]

Test,

I'm overseas right now but sure, I can measure them when I get home.  I measured a couple but I forgot the value.  I do remember a couple looked fresh and most were severely worn. The engine had 1300 SMOH and I would bet some of those plugs were that old. Interestingly, the logs only show one plug being changed, though clearly 3-4 of them are good enough for a spare. 

Huge difference in how it runs.  Like an electric motor.

[knute]

OK, PIREP!

I installed 8 new Tempest UREM38S fine wire plugs this afternoon, replacing 8 Champion massives.  Mag drops before and after were consistent (drop of around 50-60rpm doing a 1700RPM runup fairly agressively leaned), but the idle with the finewire was noticeably smoother.  Did a good run up and a couple of laps around the pattern to make sure everything was happy, inspected to verify, then took it out to stretch it's legs.

Based on my records for previous flights at the same density altitude, OAT, and power settings, the fine wire plugs appear to be showing lower peak EGT readings by 20-30 degrees.  (EDM 700 with quick reading probes)  Another data point- at the same fuel flow, full rich, sea level take off, my previous expection on #4 cylinder (my leanest) was around 1270, and now I'm seeing as low as 1240, both at 17.8 or so GPH for these conditions (both measurements represent approximately 250ROP).  Does this imply a more complete burn?  One theory on the advantage of the finewire is that because the electrode isn't as occluded as it is on the massives, that the ignition event is more efficient since the spark is more exposed; I'm intrigued by how this might relate to lower EGT readings at the same power settings and fuel flow.

I have an '66 E model, which means it has ram air (good for 1" or more depending on how long it's been since the air filter was last serviced).  Previously, the engine was not smooth enough for my liking when LOP with the ram air open with power settings above 60% (it only worked well at high altitude), and today it was perfectly happy at 3,500DA with the ram air open, 40 LOP.  (I didn't write down the fuel flow, but memory is about 10.4gph, which would be about 78% power)  With the ram air shut, it was smooth LOP all the way down well past 100 LOP when the engine pretty much stopped running.  Nice!  Previously, I could do LOP at WOT, 3500DA smooth down to about 35LOP.  (I have balanced GAMI injectors).

Granted, this test data compares the new fine wire plugs against plugs that have been in service 120 hours since my last annual in August, but even right after an annual with fresh cleaning and gapping the engine has never been this well behaved.

We'll see how they settle in over time (I have no reason to think they'll change) but my first impression is that they are a nice improvement.

YMMV, but I like them.

-Knute

'66 M20E - N6066Q - KSQL (San Carlos, CA)

[testwest]

I have to agree with Knute, I have had much better results leaning the non-GAMI engine (Lyc IO-540-S1A5, turbonormalized) to smooth LOP at 70% power in the Aerostar with the Tempest fine wires. Just got a good look at altitude yesterday, will post data in a little while.

Tempest gets it.

Hey Scott S (KSMooniac) what kind of spark plugs are you running?

[KSMooniac]

Norm, I'm running Champion massives...haven't had any real complaints so far nor do I have any other frame of reference for that matter.  I replaced the set that came in my plane a couple years ago (they had more than 900 hours IIRC) and now I have a few hundred on my current set, one of which failed earlier this year at a fuel stop.  Luckily a mechanic was still at the field and loaned me a screwdriver, wrench and socket, and then tested my old plug before selling me a new one.  Sidebar, my JPI EDM-700 told me exactly which plug was dead, turning what could have been a couple hours of diagnostics into a 30 minute nuisance and I was on my way.  

These PIREPs have me scratching my head, and looking for my anti-upgrade-fever meds.  

[Txbyker]

I am making sure my induction and injection system is super clean.  After inspecting the spark plugs I want to swap them out for some fresh ones.  The butt ends show signs of arc and the plug ends on the bottoms especially have some uneven burn.  The plugs are obviously quite old.  I don't even see an entry in the logs for the last time they were replaced.  They are Champion fine wires.

I plan to fly 8-11K altitude LOP when done.  I have read through this thread and people are having good results with Tempest finewire.  My mechanic says he would go with massive ends for better burn.  Is there a good advantage for finewire over the massive ends if you are not at flight levels?

Thanks

[testwest]

Hi Russ

You are doing it right my friend, investigate one thing at a time and share your results. If you could post what resistance values you found on your old plugs that would be great.

RAM aircraft seems to think fines provide a "little" better efficiency, see here:

http://www.ramaircraft.com/Maintenance-Tips/Spark%20Plugs-Fine-Wire-vs-Massive.htm

But George Braly from GAMI disagrees.

I would base your decision on your current economic situation....Tempest fines will be about twice as expensive.

You do have an engine analyzer, right? Can you record the data and share it?

[Txbyker]

Norman, thanks.  My A&P said the plugs should be 5KO or less and we tested several that measured in the teens all the way up to 40 and 50+.  My engine seems to run smooth and consistent but I have always run ROP too.  As far as expense, I don't mind the more expensive fine wire if they are truly better for LOP operations.

I will post results of my EDM download after plugs and tests.  I will be testing LOP probably later this week after new plugs.  GAMI's went in yesterday.  I know the stock injectors were probably LOP-able but am streamlining all components of the system.

[jetdriven]

Russ, if you dont mind, hang onto those injectors, I might need to borrow a couple to tune my new engine.

Oh and I recommend tempest fine wire. They last 2,000 hours, never need to be regapped, and dont have ceramic nose failure like teh Champions. Save the old ones, to return with your core motor. Keep the good ones.

[Txbyker]

Byron, thanks.  I'll hang on to the injectors.  GAMI website says you must return old ones but there was no docs in the box about return nor did they bill me.

I am going to try the Tempest fine wire.

 

Thanks

 

[aviatoreb]

Quote: testwest

Hi Russ

You are doing it right my friend, investigate one thing at a time and share your results. If you could post what resistance values you found on your old plugs that would be great.

RAM aircraft seems to think fines provide a "little" better efficiency, see here:

http://www.ramaircraft.com/Maintenance-Tips/Spark%20Plugs-Fine-Wire-vs-Massive.htm

But George Braly from GAMI disagrees.

I would base your decision on your current economic situation....Tempest fines will be about twice as expensive.

You do have an engine analyzer, right? Can you record the data and share it?