What Spark Plugs Do You Use?

[butchgilbert]

I was at Sun N Fun this week and talked to the Tempest Spark Plug rep.

I haven't been happy with the service life or fouling of my massive REM38E Champion plugs and I am considering swapping them for fine wire Tempest plugs ('75 M20F, IO-360A1A).

The Tempest rep says the fine wire plugs burn hotter, don't foul as easy, and are better for high altitude long range flights (I also have GAMIs and a JPI).  They run $50 each, interested in everyone else's opinions and experiences.

Thanks,

N6902V.

[jetdriven]

We have Temepest fine wire plugs.  In 220 hours, we have not fouled a single plug yet.  No runup to "burn them off".  Further, it will run 100 LOP on stock injectors.  Also, the resistance is still stable at ~1800 ohms. The Champion massives get infinite resistance and the fine wires break insulators. Its all over Beechtalk.

[drapo]

I have changed the original Champion massive REM38E for a hotter REM37BY and I'm not looking back. No more lead fouling, better fuel consumption. I made the change on my Cherokee also, a few years back and got the same positive results. And, something that is more subjective, the engine runs better... 

[testwest]

Hi Butch

We will be switching our Champion massives for Tempest fines as soon as I baseline our engine performance with the new JPI EDM-930 that is being installed right now. We have not had any runup issues yet, but I bet we find a few plugs with higher center electrode resistance than ~5000 ohms or so.

I wrote an article about Champion resistance issues for the Aerostar Owners Association last year. Everything you need to know is here:

http://www.chanceaviation.com/tempestProdInfo.htm

You can download the article from that site.

I believe "fouled plugs at runup" are actually high resistance plugs that are not sparking at all. I also think that the resistance does diminish a little when the plug bodies warm up, so the "burn off" method is actually only heating the plug bodies enough that they decide to start working. I can check this theory (or someone else can) by taking a high resistance Champion plug and heating it in an oven to 300 deg F or so and measuring the resistance again. Wear your oven mitts, though!

I also believe any attempt to establish a GAMI spread and make changes to reduce it must first start with a good set of spark plugs. I think many folks who have not been able to get good LOP engine results may have misbehaving spark plugs....but did not know it and blamed something else.

You have a JPI engine analyzer.... can you download your engine data? Do you have EZTrends plotting software? Also, for subsequent data, can you set your data rate to 2 seconds, go do a flight with the old plugs and do a real slow GAMI lean check....then after changing to new plugs, go out and repeat the same thing at the about the same weight, cg, altitude, temperature, and power? Such data would be most illuminating.

[kellym]

Quote: testwest

Hi Butch

We will be switching our Champion massives for Tempest fines as soon as I baseline our engine performance with the new JPI EDM-930 that is being installed right now. We have not had any runup issues yet, but I bet we find a few plugs with higher center electrode resistance than ~5000 ohms or so.

[Bartman]

I have over 600 hours in 5 years on my J model. The massive core plugs had about 150hrs on them when I bought the plane. After start I always lean so agressively that even opening the throttle a bit causes it to cough and sputter. Always LOP in cruise and decent until on short final, then lean on the ground again. NEVER had a "fouled plug" at runup. It just came out of Annual last week and the plugs look good i am told.

On the other hand, the trainers I flew and the club plane I occasionally fly do have "fouled plugs" on runup from time to time.

This is not hard evidence, but if what you are doing is working... I keep doing it unless there is hard evidence to suggest a change.

[MagicCarpet]

I've been using fine wire Champions in my IO-360-A1A for 10 years.  I don't run LOP because Lycoming does not endorse it.  I run 100 degrees ROP during cruise as I was taught by my instructor in 1980.  For precision, I use the "Lean Find" procedure using my JPI.  I've had not issues, at all, with run-ups or any fouling during my entire ownership.  Note:  I ALWAYS lean the mixture during TAXI (screw out 2.5 finger joints or just shy of engine roughness) so extra fuel will not gather during the taxi period.  Every annual, I rotate the top plugs to the bottom.  I take a fine wire and scrape out any goo that gathers in the bottom plugs (which is normal behavior due to any oil in the chamber settling due to gravity) and check the gaps.  IA says "keep doing what you are doing 'cause the engine is in good shape and the plugs are not showing any fouling".  The fines wires are the way to go.  Even though they are $100 each, the peace of mind knowing your aircraft is using the best is quite good....

Hope this helps.

Sincerely,

Carter
6460Q M20F
www.goairplane.com

 

[jetdriven]

Quote: MagicCarpet

I've been using fine wire Champions in my IO-360-A1A for 10 years.  I don't run LOP because Lycoming does not endorse it.  I run 100 degrees ROP during cruise as I was taught by my instructor in 1980.  For precision, I use the "Lean Find" procedure using my JPI.  I've had not issues, at all, with run-ups or any fouling during my entire ownership.  Note:  I ALWAYS lean the mixture during TAXI (screw out 2.5 finger joints or just shy of engine roughness) so extra fuel will not gather during the taxi period.  Every annual, I rotate the top plugs to the bottom.  I take a fine wire and scrape out any goo that gathers in the bottom plugs (which is normal behavior due to any oil in the chamber settling due to gravity) and check the gaps.  IA says "keep doing what you are doing 'cause the engine is in good shape and the plugs are not showing any fouling".  The fines wires are the way to go.  Even though they are $100 each, the peace of mind knowing your aircraft is using the best is quite good....

Hope this helps.

Sincerely,

Carter

6460Q M20F

www.goairplane.com

 

[drapo]

Did anybody say "CAN OF WORM!"  

[jackn]

Quote: testwest

Hi Butch

We will be switching our Champion massives for Tempest fines as soon as I baseline our engine performance with the new JPI EDM-930 that is being installed right now. We have not had any runup issues yet, but I bet we find a few plugs with higher center electrode resistance than ~5000 ohms or so.

I wrote an article about Champion resistance issues for the Aerostar Owners Association last year. Everything you need to know is here:

http://www.chanceaviation.com/tempestProdInfo.htm

You can download the article from that site.

I believe "fouled plugs at runup" are actually high resistance plugs that are not sparking at all. I also think that the resistance does diminish a little when the plug bodies warm up, so the "burn off" method is actually only heating the plug bodies enough that they decide to start working. I can check this theory (or someone else can) by taking a high resistance Champion plug and heating it in an oven to 300 deg F or so and measuring the resistance again. Wear your oven mitts, though!

I also believe any attempt to establish a GAMI spread and make changes to reduce it must first start with a good set of spark plugs. I think many folks who have not been able to get good LOP engine results may have misbehaving spark plugs....but did not know it and blamed something else.

You have a JPI engine analyzer.... can you download your engine data? Do you have EZTrends plotting software? Also, for subsequent data, can you set your data rate to 2 seconds, go do a flight with the old plugs and do a real slow GAMI lean check....then after changing to new plugs, go out and repeat the same thing at the about the same weight, cg, altitude, temperature, and power? Such data would be most illuminating.

[MagicCarpet]

Gawd,  let's not start the LOP/ROP argument again.  ROP works fine.

[butchgilbert]

Thanks all of your inputs, I'm buying fine wire Tempest plugs at Osh Kosh this year!!

[jetdriven]

Quote: MagicCarpet

Gawd,  let's not start the LOP/ROP argument again.  ROP works fine.

[MagicCarpet]

Quote: jetdriven

just not as efficient.

[Skybrd]

I hope the Tempest fine wire plugs work better than the Champion plugs. I order 4 of them today for my Experimental Wittman Tailwind. The left magneto with impulse coupling fires only the lower plugs and sometimes it's hard to start (by hand propping). If this improves the starts, I will probably buy some for my J Mooney.

[jackn]

Just a follow up on my previous post. I pulled other plugs just to compare, and found just about all had higher resistance, but looked fine. (What's going on here?) I used emory paper and compressed air to clean all electrodes back to shiny metal. resistance all declined back low. Starting and ground operations improved, and I believe CHTs were 10 degrees cooler. I mentioned this to another very experienced Mooney guy on my field. He was well aware of this. he told me he keeps 2 sets of plugs. At about halfway to annual, he'll replace the plugs, and clean/ gap the old ones. Just wanted to pass this on. I guess I'll stay with Champion massives for now.

[FlyDave]

I had about 470 hours on 8 Champion REM38E's until I changed them tonight with 8 new Tempest UREM38E's.

I checked the resistance on the tempests right out of the wrapper and got no more than 1.4 ohms on any of them. When I pulled the first old Champion out I checked the resistance with the same ohm meter and it showed showed infinite resistance. I remember reading Jack's post so I tried cleaning the top of the center electrode by scraping it to bare metal but still got the same thing. After pulling the remaining 7 Champs out I got the same thing on each one.

Can this be right? Will the plug operate with infinite resistance or am I reading something incorrectly?

I did start it up before putting the cowling back on and it definitely ran smoother. So I took it up for a short flight but the ceiling was coming down quickly and I only flew for a few minutes. I'll fly more tomorrow to see what kind of improvements I get.

But I'd like to hear what the more experienced people have to say on the infinite resistance issue.

Thanks!

[jetdriven]

it will usually fire, but the chance of misfires is higher, an more difficult to run smooth LOP.  Allso harder on mags. 

29 pages here    http://www.beechtalk.com/forums/viewtopic.php?f=37&t=59668&hilit=champion+resistance

more here   http://www.beechtalk.com/forums/viewtopic.php?f=37&t=57687&p=699662&hilit=champion+resistance+ohms#p699662

[bd32322]

Quick question, how do you measure resistance of the plugs?

Where should i be connecting the multimeter probes to?

Thanks

[jetdriven]

one end of the probe goes in the well where the spark plug lead goes. the other probe goes on the center electrode. Over 5,000 ohms is reason to suspect the plug. Use a piece of wire with the insulation stripped off to clean the button inside the plug to get good contact. There is often corrosion there, which may alter the test.

[bd32322]

one end of the probe goes in the well where the spark plug lead goes. the other probe goes on the center electrode. Over 5,000 ohms is reason to suspect the plug. Use a piece of wire with the insulation stripped off to clean the button inside the plug to get good contact. There is often corrosion there, which may alter the test.

thanks! one other question .. what should the model number be for the tempest fine wires for the io360 a3b6d? UREM38S or URHM38S - this is a 1987 m20j and thers a choice of either

thanks

[jetdriven]

One has a 3/4" (UREM) hex plug on the spark plug lead, one has a 7/8" (URHM). Both are approved for your engine, but measure what you have before ordering them. I got burned by this and had to buy a whole new set of the smaller type, the UREM.

If you need a set of the URHM I have a 220-hr set that worked great.

[bd32322]

One has a 3/4" (UREM) hex plug on the spark plug lead, one has a 7/8" (URHM). Both are approved for your engine, but measure what you have before ordering them. I got burned by this and had to buy a whole new set of the smaller type, the UREM.

If you need a set of the URHM I have a 220-hr set that worked great.

okay thanks Byron! - let me measure tomorrow and PM you if I need the 7/8ths.

[garytex]

On the tightwad side, If one wants to try fine wires, and not spend a fortune, call Aircraft Spark Plug Service in Van Nuys, CA at 818-787-5680. I've been buying used fine wires from them for 20 years, way cheap, and perfectly good. Last batch I got were Auburns. Recommended.

Gary

PS Ram in Waco has documented slightly better fuel consumption specifics, especially at altitude, using fine wires