LOP with Fine Wire vs Massive Plugs

[FLYFST]

For those of you that run your engine LOP, do you use fine wire or massive plugs?  If you switched from one to the other, did you notice any improvement in LOP operations?  I currently have Champion massive plugs that have less than 200 hours on them and some are close to their useful limits so I am considering changing to fine wires.  I run 10 to 20 LOP at 65% Hp for most operations but will run 100+ ROP when I want to fly as fast as I can.  Since I am considering the much higher purchase price of the fine wire plugs I wanted to reach out and ask about your experience with massive vs fine wire for mostly LOP operations.  Note that I am not asking about massive vs fine wire in general, or LOP vs ROP, both topics that have already been widely, and enthusiastically discussed in MooneySpace and other venues.

Thanks in advance - Hank

[alextstone]

I first learned to run LOP after installing GAMI’s then I switched to fine wire plugs.  I did notice a difference in the smoothness of the engine and the ability to run further into LOP by a small margin.  Temps are a bit lower too.

[Shadrach]

Color me skeptical. Smooth running at lean efficiency ratios is a product of even fuel/air distribution. This ensures that each individual cylinder is more or less contributing the same power pulse in terms of force and duration. Regardless of plug type, all of these engines run twin spark ignition. Why would fine wire have the effect of normalizing F/A ratios?  I don’t buy it. Fine wires may allow for the consistent ignition of leaner mixture settings, but who care? As an example,  I run tempest massives and can run far leaner then I would want or need.  I can smoothly run 90ish LOP depending on altitude more than 100LOP down low. Perhaps with fine wires it would run to 120LOP but why would I want to do that? Maybe there’s a benefit in a turbo engine where 80 or 90LOP is a useable setting. For NA engines, I think it’s a lot of hype. I’ve asked for massive vs fine wire data but I’ve never seen it produced.

[Shadrach]

55 minutes ago, FLYFST said:

For those of you that run your engine LOP, do you use fine wire or massive plugs?  If you switched from one to the other, did you notice any improvement in LOP operations?  I currently have Champion massive plugs that have less than 200 hours on them and some are close to their useful limits so I am considering changing to fine wires.  I run 10 to 20 LOP at 65% Hp for most operations but will run 100+ ROP when I want to fly as fast as I can.  Since I am considering the much higher purchase price of the fine wire plugs I wanted to reach out and ask about your experience with massive vs fine wire for mostly LOP operations.  Note that I am not asking about massive vs fine wire in general, or LOP vs ROP, both topics that have already been widely, and enthusiastically discussed in MooneySpace and other venues.

Thanks in advance - Hank

How do massive electrode plugs approach the end of useful life in just 200hrs? 

[FLYFST]

How do massive electrode plugs approach the end of useful life in just 200hrs? 

No idea, my previous massive plugs lasted over 300 hours. On the current set only some are approaching the limit.


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[Bolter]

12 minutes ago, Shadrach said:

How do massive electrode plugs approach the end of useful life in just 200hrs? 

In my case, by 270 hours, I had cracked 2 Champion fat electrode plugs (2 different cylinders at different occasions).  That was end of life in terms of trusting them.  Got 8 new Tempests.  The condition of the uncracked and cracked Champions' electrodes was great otherwise.

[Shadrach]

@FLYFST @Dan at S43 I have never had the need to retire a plug before 500hrs. Some go quite a bit longer. Are you guys rotating them? The cracked electrodes sound like a QC issue or a drop.

Edited April 12, 2019 by Shadrach

[Bolter]

Just now, Shadrach said:

@FLYFST @Dan at S43 I have never had the need to retire a plug before 500hrs. Some go quite a bit longer. Are you guys rotating them? The cracked electrodes sound like a QC issue or a drop.

I believe a QC issue at Champion.  I bought 8 new plugs because I wanted a clean slate.  I know these were never dropped.  I sent the good and bad ones to Champion with a letter explaining the history, and that 2 plugs, 100 hours apart and so early in life is a trend, not an anomaly.  Especially on an engine that had not a single other squawk in 800 hours in 8 years that I have owned it (400 hours on the engine when I got it).   

[PT20J]

Curious what “useful limit” you are measuring and if you are rotating even to odd, not just top to bottom and how often. Not doubting your observation, but I’ve just always gotten much longer life. 

What I would really be interested in is a comparison of fine wire and BY massives - anyone done that?  

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[Bob_Belville]

I can't comment on LOP with Champion massives. I bought this E in Feb. 2012 with Champions in it but switched to Tempest fine wires after 18 hours that were unsatisfactory. I've flown the fine wires over 500 hours and I can run deep LOP though power drops off pretty dramatically as I go more than 20-30 LOP.  

[PT20J]

25 minutes ago, Bob_Belville said:

I can't comment on LOP with Champion massives. I bought this E in Feb. 2012 with Champions in it but switched to Tempest fine wires after 18 hours that were unsatisfactory. I've flown the fine wires over 500 hours and I can run deep LOP though power drops off pretty dramatically as I go more than 20-30 LOP.  

I think some folks get carried away with LOP thinking that if a little is good, a lot must be better. If you go really lean, the fuel flow drops off impressively. But, the power and thus the airspeed drops off even faster. The BSFC actually increases and you use more gas to get where you’re going later. 

[FLYFST]

[mention=7952]FLYFST[/mention] [mention=8089]Dan at S43[/mention] I have never had the need to retire a plug before 500hrs. Some go quite a bit longer. Are you guys rotating them? The cracked electrodes sound like a QC issue or a drop.

I clean, regap if needed, and rotate at oil changes every 25 - 30 hrs. The nearing the service limit is based on using the champion gauge that indirectly measures how much of the serviceable electrode is left. Mine are not cracked, just wearing out faster than expected and in need of future replacement. That is why I asked the group about experience with LOP and fine wire vs massive.


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[FLYFST]

I think some folks get carried away with LOP thinking that if a little is good, a lot must be better. If you go really lean, the fuel flow drops off impressively. But, the power and thus the airspeed drops off even faster. The BSFC actually increases and you use more gas to get where you’re going later. 

In my case it is typically 10 to 20 LOP at 65% Hp


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[jaylw314]

I started with Champion massives and changed 4 of them out for Tempest fine-wires.  Other than maybe some slightly easier starting, I can't say I've noticed any obvious performance difference running LOP (or any mixture for that matter).

[StevenL757]

8 hours ago, FLYFST said:

For those of you that run your engine LOP, do you use fine wire or massive plugs?  If you switched from one to the other, did you notice any improvement in LOP operations?  I currently have Champion massive plugs that have less than 200 hours on them and some are close to their useful limits so I am considering changing to fine wires.  I run 10 to 20 LOP at 65% Hp for most operations but will run 100+ ROP when I want to fly as fast as I can.  Since I am considering the much higher purchase price of the fine wire plugs I wanted to reach out and ask about your experience with massive vs fine wire for mostly LOP operations.  Note that I am not asking about massive vs fine wire in general, or LOP vs ROP, both topics that have already been widely, and enthusiastically discussed in MooneySpace and other venues.

Thanks in advance - Hank

Tempest Iridium fine wires without a doubt.  Much smoother engine, more stable LOP operations, and the plugs will last well over 1000 hours...possibly longer if taken care of (inspected, cleaned at least every annual and in between).

The value-add far outweighs the added cost vs. massive.  After running out my previous engine, the first thing I did when the new/factory-rebuilt engine was installed was sell the box of massives they provided and install the fine wire plugs.  One of the best decisions I’ve ever made. 

Steve

[FLYFST]

I started with Champion massives and changed 4 of them out for Tempest fine-wires.  Other than maybe some slightly easier starting, I can't say I've noticed any obvious performance difference running LOP (or any mixture for that matter).

Thanks, that is exactly the type of feedback that I was hoping for.


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[FLYFST]

Tempest Iridium fine wires without a doubt.  Much smoother engine, more stable LOP operations, and the plugs will last well over 1000 hours...possibly longer if taken care of (inspected, cleaned at least every annual and in between).
The value-add far outweighs the added cost vs. massive.  After running out my previous engine, the first thing I did when the new/factory-rebuilt engine was installed was sell the box of massives they provided and install the fine wire plugs.  One of the best decisions I’ve ever made. 
Steve

Thanks, that is the type of feedback I was hoping for.


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[Shadrach]

8 hours ago, FLYFST said:

In my case it is typically 10 to 20 LOP at 65% Hp


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10LOP for a NA Lycoming should be adequate for almost any throttle setting unless below a DA of 3000ft. It’s good that you’re not going “overboard” on the lean side but you may be leaving speed on the table if 65% (8.5gph) is your limit. There may be scenarios where you can be LOP at higher power levels that would beneficial. I often stay low into altitude increasing headwinds and run max power LOP (a good strategy at 2500’msl or less in the flatlands). My Taildragger buddies like to fly low and slow. I will fly low and fast to avoid 30kts on the nose at a higher altitude, fuel flow down low when LOP is is the mid 10gph range.

Edited April 12, 2019 by Shadrach

[Shadrach]

5 hours ago, FLYFST said:

Thanks, that is the type of feedback I was hoping for.


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Do keep in mind that when someone spends 3X the cost of a massive (~$1000 6cyl) for a set of spark plugs they really do feel a drive to love them...

Both Tempest and Champion have unlimited plugs for testing fine wires vs massives. Does anyone know of any actual manufacturer (or alternate source) data to support all of the anecdotal claims? Seems to me that if they could, the manufacturer’s would be making the same claims that fine-wire owners are making...but they are not.

Edited April 12, 2019 by Shadrach

[FLYFST]

Seems to me that if they could, the manufacturer’s would be making the same claims that fine-wire owners are making...but they are not.

Well said and insightful.


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[FLYFST]

There may be scenarios where you can be LOP at higher power levels that would beneficial. I often stay low into altitude increasing headwinds and run max power LOP (a good strategy at 2500’msl or less in the flatlands). My Taildragger buddies like to fly low and slow. I will fly low and fast to avoid 30kts on the nose at a higher altitude, fuel flow down low when LOP is is the mid 10gph range.

Agreed and I do the same. I typically start leaning at 75% HP and 100+ ROP, then as I lean below peak the power has dropped to around 65%, but at that setting I see 9.5 to 9.0 gph, and rarely below 9 gph.

My thinking, of which I am not confident, is that the fine wire plugs MAY allow for a more efficient combustion LOP and therefore smoother operations. For ROP operations I see little added value in the extra cost of the fine wire plugs.


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[FLYFST]

Tempest Iridium fine wires without a doubt.  Much smoother engine, more stable LOP operations, and the plugs will last well over 1000 hours...possibly longer if taken care of (inspected, cleaned at least every annual and in between).

Steve

Thanks, that is the type of response I have been hoping for.


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[mike_elliott]

12 hours ago, alextstone said:

I first learned to run LOP after installing GAMI’s then I switched to fine wire plugs.  I did notice a difference in the smoothness of the engine and the ability to run further into LOP by a small margin.  Temps are a bit lower too.

The Bravo's LOP ops are highly dependent on a "good" ignition system. Any weakness in the spark really affects them, even with well balanced flows to each cylinder.

[StevenL757]

Absolutely true.  I can't speak for the TLS/Bravo or the "J", but on the Ovation, the best ignition system you can have for the IO550 engine platform consists of the following...

* Bendix mags

* Gold Seal ignition harness

* Tempest fine-wire plugs (all cylinders - top and bottom)

Steve

[PT20J]

If I understand the theory correctly, the fine wires are supposed to ignite weak mixtures more rapidly because the electrodes project further into the combustion chamber whereas the the massives could have the spark jump the gap at the base of the electrodes up inside the plug. So, it seems that the BY plugs might do the same thing (if the theory is correct) at lower initial cost. The long term cost is probably a wash as the longer life is claimed by some to offset the higher cost. 

I think @Shadrach had a good point though: if the performance difference were repeatedly measurable, the Champion and Tempest marketing departments would likely be touting it. But, if you tried the fine wires and are convinced there is an improvement, good for you. For others, your mileage may vary. I'm going to try the Tempest BY plugs when the Champion plugs that came with my rebuilt engine wear out (which may only be a couple of hundred hours - we'll see.) Right now, it's running very well on the Champs both LOP and ROP.

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