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  #1  
Old 06-23-2021, 10:27 AM
sahrens's Avatar
sahrens sahrens is offline
 
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Default NGK BR8ES 3961 replacement

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
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  #2  
Old 06-23-2021, 10:32 AM
lr172 lr172 is offline
 
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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
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  #3  
Old 06-23-2021, 10:43 AM
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sahrens sahrens is offline
 
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Default Denso

I spoke with EMagAir about replacement plugs. The gentleman I spoke with suggested Denso 5312-ik27 as an alternative but added they had not done any testing with this plug.

https://www.densoproducts.com/denso-...wer-spark-plug

Has anyone tried this plug?
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Last edited by sahrens : 06-23-2021 at 10:43 AM. Reason: Clarity
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  #4  
Old 06-23-2021, 11:15 AM
swjohnsey swjohnsey is offline
 
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Default

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.
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  #5  
Old 06-23-2021, 12:24 PM
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Gash Gash is offline
 
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I'm running Denso ik27 plugs in my IO-390 with dual PMAGs. 300 hours and no problems at all.
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  #6  
Old 06-23-2021, 02:00 PM
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sahrens sahrens is offline
 
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Default 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.
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  #7  
Old 06-23-2021, 03:30 PM
swjohnsey swjohnsey is offline
 
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I haven't noticed a difference. I can't think of a reason a different plug would make and engine run hotter.
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  #8  
Old 06-23-2021, 04:18 PM
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sahrens sahrens is offline
 
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Default 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
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  #9  
Old 06-23-2021, 04:27 PM
Northernliving Northernliving is online now
 
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Quote:
Originally Posted by Gash View Post
I'm running Denso ik27 plugs in my IO-390 with dual PMAGs. 300 hours and no problems at all.
Denso L14-U or Autolite 386s also work fine on a IO-360s without the need for the adapters (18mm threads). They are around $2 each.
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  #10  
Old 06-23-2021, 04:30 PM
Northernliving Northernliving is online now
 
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Quote:
Originally Posted by swjohnsey View Post
I haven't noticed a difference. I can't think of a reason a different plug would make and engine run hotter.
“When making spark plug heat range changes, it is better to err on the side of too cold a plug. Running too cold a plug can only cause it to foul out, whereas running too hot a plug can cause severe engine damage.”

https://www.ngk.com/what-is-a-spark-plugs-heat-range-2
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