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Hello folks. 

I'm debating to purchase a TEMPEST IRIDIUM FINE WIRE SPARK PLUG UREM38S to install on a 1983 Mooney M20J. I heard lots of good things but my mechanic said its just waist of money. My folks that i know they had them installed they are very happy with the performance and the fact you'll be able to do LOP better with them. I do not have a Gami Injectors. 

Please share your thoughts and your experience if you had them. Thank you  

Edited by Shawn26

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They're great plugs. Long life, better quality, better LOP ops. Have had them for many years in my J.

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I know some split the difference, and use them only on the bottom, where their anti fouling properties benefit you most.


Tom

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I think it’s a no brainer if you’re going to keep the airplane.  The higher purchase price will be offset by longer life and slightly better performance (I.e., lower fuel consumption).

 

 

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Recommend them highly. Would not use Champion, had problems with them. 

Edited by Wistarmo

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My IA concurs with your mechanic.   If you have oily cylinders, the BY plug has a longer nose and is also an option for some engines.

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Fine wire electrodes are smaller and more exposed than massives where the spark can occur deeper down in the plug and this is the theory why they may perform better with weak mixture strengths like LOP and starting. 

What I would find interesting is a comparison of fine wires and BY massives. Anyone tried both in the same engine?

Skip

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Thank you. Mainly I want to change it for performance. I don’t have any oil burning issue or other problems with the engine. I was considering Gami for better LOP, and one of my friend said to first start with Fine Wire Plug for better performance and LOP operation.




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Many find the Lycoming IO-360s run pretty well LOP on the stock injectors. You might want to do a GAMI spread to see what you’ve got. GAMIjectors may not make enough difference to be worth it. They best help the big Continentals with that horrible log runner induction system. There is really no advantage to running leaner than the minimum BSFC mixture.

Skip

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On 8/2/2019 at 4:31 PM, Shawn26 said:

Hello folks. 

I'm debating to purchase a TEMPEST IRIDIUM FINE WIRE SPARK PLUG UREM38S to install on a 1983 Mooney M20J. I heard lots of good things but my mechanic said its just waist of money. My folks that i know they had them installed they are very happy with the performance and the fact you'll be able to do LOP better with them. I do not have a Gami Injectors. 

Please share your thoughts and your experience if you had them. Thank you  

As far as being a waste of money, ask your mechanic to qualify the statement.  I’ve run them in 2 different engines and have had nothing but smooth operations...especially with LOP operations.  I can assure you they’re more than worth the extra spend.

Steve

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The previous owner of my aircraft installed Tempest fine wires at around 1300 hours, and I ran the same ones until I did the engine exchange at around 2200 hours. The factory re-man came with Champion massives - after 100 hours the wear was obvious to the naked eye, and my A&P thought I *might* get as much as 300 hours out of them. I changed them to Tempest fine wires before coming to Osh

Edited by Awful_Charlie
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They last more than twice as long and perform better - how could they possibly be a waste of money??


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Curious how often you have to regap your fine wires?

Do you use a gapping tool or just small needle nose pliers as Tempest recommends?

Any problems breaking electrodes when gapping?

Skip

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They are fragile electrodes, but basically you re-gap every 1000 hours.id guess they pay fro themselves in labor savings. You pull them out. Look at them. Maybe snag some lead deposits with a dental pick.  Then reinstall. No blasting. In fact it’s not supposed to be done. 

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We have also had excellent experience with fine wire plugs.  Never had to gap them after installation because they don't erode!  We have never had fouling problems and always smooth as silk.  I wouldn't use anything else.

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I actually starting sending mine to the Spark Plug lady, "Aircraft Spark Plug Service" 818-599-6139 at annual time. She cleans them, checks gap and checks internal resistance although the Tempest plugs don't have a resistance issue like the old champion design with removable resistor, they should still be tested. She returns them with new copper gasket. I learned about her from Mike B who also uses her and recommended her. One less thing I need to do during annual. But I have the special champion gapping tool and wouldn't touch an electrode without it - as Byron said above they are way to fragile to risk breaking the electrode.  

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Gami's and fine wire in my 550 Continental.  Since then CHT's and EGT's  are straight lined across the EDM930.

Only regret is that I should have installed them sooner.

Best,

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9 hours ago, PT20J said:

What I would find interesting is a comparison of fine wires and BY massives. Anyone tried both in the same engine?

Skip

I had BY Champions in the bottom and Tempest Fine wire in the top.    The number 4 cylinder tends to be a little oily.    About 70 hours and then one of the Fine wires lost the center electrode.   It might have been a little smoother when the fine wires were replaced with Tempest massives in the top.   As far as running much smoother redoing the fuel servo and 2 new injectors and having everything flow tested seemed to be the largest improvement

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Known issues...

Champion plugs have had the increasing resistance challenge that has surprised many aviators over time.... a crummy never ending problem...

Tempest plugs have had the missing center electrode that affected a few MSers...

Tempest was pretty straight forwards with replacing failed plugs and actively sought a fix for the manufacturing problem...

 

When your mechanic says he doesn’t like something... it is OK to follow up with a question, like... why?

Often, they have great input that is worthwhile knowing...  or it could be an issue that doesn’t apply to your airframe...

PP thoughts only, not a mechanic...

Best regards,

-a-

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19 minutes ago, carusoam said:

Known issues...

Champion plugs have had the increasing resistance challenge that has surprised many aviators over time.... a crummy never ending problem...

Tempest plugs have had the missing center electrode that affected a few MSers...

Tempest was pretty straight forwards with replacing failed plugs and actively sought a fix for the manufacturing problem...

 

When your mechanic says he doesn’t like something... it is OK to follow up with a question, like... why?

Often, they have great input that is worthwhile knowing...  or it could be an issue that doesn’t apply to your airframe...

PP thoughts only, not a mechanic...

Best regards,

-a-

I believe Champion has fixed the resistor  problem with a new design more like Tempest’s. 

I believe Tempest has fixed the fine wire center electrode problem.

Mechanics are frequently by nature risk adverse (not necessarily a bad thing) and once bitten, are twice shy in my experience. 

Skip

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There are some things to improve with a 70 year old engine design.   Electronic ignition and electronic fuel injection would probably be the most beneficial.  

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2 hours ago, Yetti said:

There are some things to improve with a 70 year old engine design.   Electronic ignition and electronic fuel injection would probably be the most beneficial.  

It is an old design, but are the new engines the same as 70 years ago?  Have they been optimized in any way?  Has the build improved, the clearance consistency and specification?  The metallurgy?

In a different but comparable question.  My son does civil war re-enacting.  For his 18th birthday we just got him a 1856 design Enfield front loading musket, true to the weapons of the civl war.  But it is a new build to old designs.  As I mentioned above the specs are much Truer, and the metallurgy is much better, so it is a significantly Truer and safer gun than the original museum pieces.  And of course cheaper to buy.

Edited by aviatoreb

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2 hours ago, aviatoreb said:

It is an old design, but are the new engines the same as 70 years ago?  Pretty much

 

Have they been optimized in any way?  going to the 390 roller cam is a large improvement.   But lots of money for that.

Has the build improved, the clearance consistency and specification?  tolerances have remained the same.   Old engine, old manuals.

 

The metallurgy?  There is a general theme that there is a slip in metallurgy in the cam or followers in the 1990s to early 2000s    Now people are trying some of the new coatings on the original design.

 

It's a boxer design.   Another boxer designed engine by BMW on their motorcycles probably uses lots of their WWII airplane technology.   A generation change happened in say early 2000 with the 1100 to 1200 engine.

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