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NGK BR8ES 3961 replacement

sahrens

Well Known Member
I'm probably late to the party on this, but the manufacturer has discontinued the BR8ES 3961 plug. There is listing of alternatives from Champion, etc. Before I go down that road I was hoping folks had found an acceptable alternative.

I believe you can still get the BR8ES 5422 with the removable terminal but I would prefer to not use those. I have tried the NGK BR8EIX Iridium plugs but the engine ran hotter on those plugs (O-360-A1A.)

What is the collective wisdom on an alternative plug?

Thanks
 
I use the std BR8es plug. Just put a dab of red loctite on the threads and re-install the cap. Just be sure that the loctite doesn't touch the flat base area of the plug and tip to ensure good continuity.

WOrks well for me.

Larry
 
That is the plug now recommended by Light Speed. I'm running them in my IO-360-EXP. I think they also come with both types of terminals.
 
I'm running Denso ik27 plugs in my IO-390 with dual PMAGs. 300 hours and no problems at all.
 
Desno and heat

For those of you running the Denso IK27 did you notice if the engine ran hotter or about the same after you started using them? Of course this assumes you were running something else to begin with.

Thanks for your replies.
 
I haven't noticed a difference. I can't think of a reason a different plug would make and engine run hotter.
 
Temp range

It is my understanding that a cold-plug would normally be recommended for a lower compression engine like my O-360 with 8.5-1 compression ratio. The cold plug would transfer the heat away from the plug to the cylinder more easily than a hot plug.

In order to handle CHTs on a heat soaked engine during take-off and climb out a slightly hotter plug seems to help. Not talking a huge temperature difference but I'll take what I can get. So my question is about the experienced heat range of the Iridium plugs. Did folks notice any change in the CHTs during operation, good or bad?

If I have that wrong please set me straight
 
For those of you running the Denso IK27 did you notice if the engine ran hotter or about the same after you started using them? Of course this assumes you were running something else to begin with.

Thanks for your replies.

It's all I've used on my IO-390. I run LOP about 8.5 gph and CHTs are parked around 350F.
 
That is the plug not the engine temp as measured by EGT, CHT or oil temperature. You can have a too hot plug in a too cold engine or a too cold plug in a too hot engine.
 
Interesting to hear this. I just bought 8 new plugs a couple of weeks ago for my annual. $23 total at O'Reilly Auto Parts! Maybe I should stock up?
 
Shortage

Even EmagAir said they were having problems getting them. If you can get them you should
 
plug

I'm pretty sure the colder the plug, the hotter the cylinder head will be. The colder plug transfers more heat to the head hence a colder plug.
 
For the guys who are stocking up on BR8ES plugs, you can usually find them cheapest at rockauto.com Buy them up in bulk while you still can!
 
As ever, there is more to spark plug heat than just CHT. I used to run BR8ES in an O-320 but always suffered higher plug wear than I though I should - central electrode was significantly worn after 50 hrs. I switched to BR9ES, plug wear decreased with no other noticeable changes.

Pete
 
If we were changing the NGK plugs every 100hrs, what replacement interval should we be using for the Denso 5312-ik27 as they appear to be more of a weapons grade plug.

Tom
2x PMag IO-360 M1B RV-7
 
I’ve been use it the br8 ecm 3035 plug for pas 8 years and have had no issues. It’s a little pricy at $9 a plug.
 
I just secured a 12 year supply of the 3961 plugs. They just work. I'll still throw them in the garbage at every annual inspection. I love not having to worry about futzing around with spark plugs!
 
For the guys who are stocking up on BR8ES plugs, you can usually find them cheapest at rockauto.com Buy them up in bulk while you still can!

Door closed on that deal, apparently. You can now buy only two plugs.
 
Ditto...

I just secured a 12 year supply of the 3961 plugs. They just work. I'll still throw them in the garbage at every annual inspection. I love not having to worry about futzing around with spark plugs!

Just got my own 10 year supply from the local Advance Auto...That will get me close enough to the point where I will be considering whether it's a smart thing to start thinking about stopping flying due to age...

I agree with you...I don't like doing anything with plugs other than pull and replace!

Thanks to the OP for the heads up!

Rob
 
west marine

West Marine has the 3961 plugs both on line and in-stock in the stores in our area. $2.99/plug.
 
I have two P-mags and have been using the NGK BR9EIX (p/n 3089 - solid tip Iridium). My CHTs are great. I can buy 4-packs on eBay for $15 with free shipping ($3.75 each). And Iridium should last longer but at $3.75 no big deal.
 
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I have two P-mags and have been using the NGK BR9EIX (p/n 3089 - solid tip Iridium). My CHTs are great. I can buy 4-packs on eBay for $15 with free shipping ($3.75 each). And Iridium should last longer but at $3.75 no big deal.

I've heard of counterfeit plugs being sold on ebay, just a heads up.
 
Knock off plugs

From personal awareness (wasn’t me but a friends car we were prepping) you have to have a genuine baseline to compare it to. From there it’s easy, at least the ones we had were obvious.
 
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Great,,
Something else to worry about.

I just stocked up due to the shortage, from a farm supply company (Blain's Farm & Fleet). Guess I'll have to check.

After watching the videos, spotting a fake is not going to be easy, The differences are ever so subtle, and I would not rely on any lettering/lot numbers to distinguish a fake from real. Seems to me a simple change to how the fakes are stamped (different dies) would mask that. Even the shape of the ground electrode doesn't seem to be a certain give -away as one video shows a counterfeit with a nicely curved one (vs squared).

Ugh!!
 
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I just ordered a bunch of BR8ES 3961 plugs from NAPA. It'll be interesting to see if I receive them. Supposed to arrive on July 20th.

I'm up to 3 Pmags now. 2 on a Glasair and 1 on my RV3. I'm hoping to buy enough plugs to carry me through to the point where many people smarter than me have agreed on a replacement and I can just follow along! :D
 
I wouldn't be too concerned about fake plugs as I have seen a number of aircraft plugs fail with the insulator blowing out. Even the best quality plugs definitely can and do fail.
 
I wouldn't be too concerned about fake plugs as I have seen a number of aircraft plugs fail with the insulator blowing out. Even the best quality plugs definitely can and do fail.
I also noticed that most of those “Identify a Fake Plug” links are for the NGK Iridium type, which sell for north of $10.
Much different than our beloved #3961, which were normally around $2.

Perhaps I am naive, but there doesn’t seem to be much of a sound marketing potential to produce counterfeits.

I guess that could change however, once the supply dries up and demand calls for a higher price.
 
I also noticed that most of those “Identify a Fake Plug” links are for the NGK Iridium type, which sell for north of $10.
Much different than our beloved #3961, which were normally around $2.

Perhaps I am naive, but there doesn’t seem to be much of a sound marketing potential to produce counterfeits.

I guess that could change however, once the supply dries up and demand calls for a higher price.

+1

Idk about you guys but I only buy spark plugs from a reputable NGK approved supplier!

Most of the auto parts suppliers are (NAPA for me). Amazon is not! In fact, many of the fake spark plugs you see in those videos are coming from Amazon.
 
I also noticed that most of those “Identify a Fake Plug” links are for the NGK Iridium type, which sell for north of $10.
Much different than our beloved #3961, which were normally around $2.

Great point and makes sense.

There are no performance advantages to iridium plugs but they last longer. In some of the cars I own iridiums aren't recommended due to the higher resistance of the electrode.
 
For what it’s worth a representative from NGK told me via email that the 3961 hasn’t been discontinued but is in “global backorder”. She noted there may be more supply available in blister packs than the bulk packs.

Of course this was after I ordered my 4 year stock :rolleyes:
 
For what it’s worth a representative from NGK told me via email that the 3961 hasn’t been discontinued but is in “global backorder”. She noted there may be more supply available in blister packs than the bulk packs.

Of course this was after I ordered my 4 year stock :rolleyes:

Brad at Emagair told me the same thing yesterday and recommended I continue to check all the usual sources.

Yesterday afternoon I found some on Amazon and ordered a set.

https://www.amazon.com/NGK-BR8ES-SO...rk+Plug+-+BR8ES,+4+Pack&qid=1626551036&sr=8-2

Good luck,

Dean
 
This seems to echo the global chip shortage. A few chips are delayed because of the pandemic, then buyers panic and try to tie up their next 4 years requirements exacerbating the problem, for most of these chips to just sit on a buyers shelf for the next 4 years, and making life suck for people that really did need those chips. Humans are their own worst enemies. The upside is that out of all of this alternate cheaper and better chips will be developed, which will lead to massive deflationary pressures in chip manufacturing, and the same will apply to spark plugs. We’ve already seen this with the crashing of the lumber market which everyone was projecting would go to the moon. I guess moral of the story is don’t buy a boatload of plugs for a stupidly high price, because this is only a transitionary issue and the world hasn’t forgotten how to build spark plugs.
Tom.
 
Paid $2.88/each yesterday at an auto parts store.

I paid about the same for 30 from NAPA about a week ago. I bought a two year supply plus some spares to get through the supply chain issues. I don’t believe there is a need to stock up on larger quantities.
 
Those are about double the normal price

Very interesting. Yesterday, when I placed the order, the price was $14.99 for a 4-pack. This morning, I just clicked on the amazon link in my original post and now see that it now shows a price of $7.44 each with no 4-pack option. Amazon apparently has some very elastic pricing strategies.

Jereme - Thanks for the heads up on Amazon not being an authorized distributor for NGK. It had never occurred to me to worry about counterfeit spark plugs. I'll check them over closely for anything that looks amiss.

Regards,

Dean
 
You can Google counterfeit NGK spark plugs and find a lot of info there. This is very widespread on platforms like Amazon.

Many other companies like MSD, Walbro and Bosch have warnings on their websites about counterfeits and some have launched legal action it's so bad.

The same is true for items like SD cards. On one vendor site, an outside investigation showed something over 60% of cards offered there were fakes...

On the spark plugs, the fake ones have been known to shed ground electrodes on occasion which may not be good for your engine if it lodges in the piston crown or chamber and gets smashed into a few hundred thousand times.
 
Just another data point - I just ordered some BR8ES-3961 NGKs from Aircraft Spruce, $2.65 (vs $2.99 from NAPA). Presumably ACS is reliable with respect to counterfeits!
 
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