Looking for ideal spark plug

[MooneyBob]

I have IO 360 A3B6 engine in my M20J.

What is the best spark plug for the engine?  I am located in NJ, if weather has anything to do with it.

Also, I was told that bottom plugs could be different from the top ones ( fine wire ???) as my engine is not super smooth while taxiing around 1000 - 1200 RPM. It misses regularly. I lean while taxiing. ( BTW, what is the best practice to lean on taxi? ).

Thanks.

 

 

[Hank]

Leaning on the ground will reduce plug fouling. Typical advice is to lean enough that if you give it significant power the engine will choke. For my O-360, I move the red lever about halfway to Idle/Cutoff.

 

There has been much discussion here about the benefit of fine wire plugs, mostly having to do with LOP operations. My carbed engine doesn't like LOP, and I am happy with my Champion massives [replaced in 2012].

[MB65E]

I run 37BY Tempest plugs in our IO-360-A1A in the Mooney. I have had good luck with them in other installs. Proven results on several cases made me a believer. A lot of the engine shops run them on their race engines. Do a search here, it's been discussed in detail.

-Matt

[Parker_Woodruff]

Tempest Fine Wire plugs for all 8.

 

You may also want to look into fixing any induction leaks if they exist.  That's a common reason the aircraft will not run well at lower power settings on the ground.

 

Aggressive leaning on the ground is also important.

[carusoam]

Be aware of a certain champion? plug...for it's troublesome manufacturing issue.

Unfortunately I don't remember the detail...

Search for the details it will come up quickly,

-a-

[BigTex]

I use tempest fine wires top and bottom and saw huge difference in the way the engine starts up and seems to run smoother.

For leaning, as soon as the engine stabilizes, I pull the mixture out almost to cutoff which happens to be the length of my index finger.

[PTK]

I'm running standard Champion massives with no issues.

I lean aggressively on the ground and operate well LOP.

Typically 70 or 80 degrees LOP and GAMI spreads of 0.0-0.1.

[scottfromiowa]

Tempest massives after Champion massives. WAY better plug in my A1A.

[Super Dave]

I just installed a new set of Tempest massives in our IO360A1A but haven't flown them yet, maybe tomorrow. Several of the Champion massives that came out tested >5000 ohm. It's anecdotal, but I've read/heard much negative about Champions, several positive reports from those who have switched from Champion to Tempest, and Tempests are cheaper. The only argument I've read supporting Champions over Tempests is "it's what I've always used".

As far as leaning on the ground, I like to let the engine stabilize at 1000 RPM and then lean to just beyond the RPM rise. Unless you see the rise in RPM, you don't really know if you are leaning far enough. This turns out to be fairly close to idle cutoff in our plane, and does not allow much over 1200 RPM without the engine coughing. For run up, I enrichen to mid range, set run up RPM, and then lean a bit past the RPM rise. After run up, it's back to 1000RPM, and again, lean just past RPM rise. It sounds kind of fussy, but it really only takes a second or two to find the RPM rise.

[jetdriven]

Be aware of a certain champion? plug...for it's troublesome manufacturing issue.

Unfortunately I don't remember the detail...

Search for the details it will come up quickly,

-a-

Champion fine wires will crack insulators which can cause bad things like preignition to happen. I haven't heard of this problem with the Champion massives. However, all the Champion plugs use a carbon stacked resistor which breaks down and causes high resistance, along with internal arcing, and I bet is a cause of all these mag failures we are getting.

[wishboneash]

I used to have Champion massives (came with the plane when I bought it). The resistance on some of the plugs were over 20k ohms.. I switched to Tempest massives a year ago. Much more consistent resistance under 4k ohms.

[carusoam]

Thanks for the memory aid, Byron!

-a-

[Bob_Belville]

I went from Champion massives to Tempest fine wire shortly after buying this '66E a couple of years ago. That was the end of fouled plugs and hard starting. And I expect the $50 plugs last the life of the engine. (Half the massives had been replaced in the 500 hours that were on the engine before I switched.