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Long reach (26.5mm) auto spark plugs

APACHE 56

Well Known Member
I am looking for a manufacturer and part number for a long reach auto plug for my IO-390. I have the long reach inserts and have been using an iridium Denso plug. More than one source has told me that iridium with electronic ignitions is not cost effective.
The NGK BR8ES is a good plug and if there is a long reach version that would be fine. I've tried the parts stores and online references with no joy.

thanks,
Don
 
I am looking for a manufacturer and part number for a long reach auto plug for my IO-390. I have the long reach inserts and have been using an iridium Denso plug. More than one source has told me that iridium with electronic ignitions is not cost effective.
The NGK BR8ES is a good plug and if there is a long reach version that would be fine. I've tried the parts stores and online references with no joy.

thanks,
Don
Just wondering if you found a part number for the long reach NGK plugs for the IO390? My search also has not turned up a part#
 
What long reach plugs are you using in your angle valve engines (IO-360, IO-390, IO-400, etc.)?

Thanks for your help!
 
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More than one source has told me that iridium with electronic ignitions is not cost effective.
thanks,
Don

Eh? Any more info on this statement? Lots of Ir plugs in our autos which are all electronic ign....why would it be any diff for electronic Lycos?
 
Eh? Any more info on this statement? Lots of Ir plugs in our autos which are all electronic ign....why would it be any diff for electronic Lycos?

I suspect Don means "...if you replace them at each condition inspection." They cost twice as much.

FWIW, I'm running IKH27's over 200 hours, currently alternating top and bottom replacements at two year intervals. This one had 213 hours:

Plug%20IKH27%20213%20Hrs%202.jpg


Plug%20IKH27%20213%20Hrs%203.jpg


Gap grows a little, but all have looked like they would go another 200. I may try it at some future point. Right now I have another experiment going, and I don't want any possible effect on results.
 
Why Long Reach Plugs?

When does one use 'long reach' plugs? Are they used only on angle valve engines?
 
These are a 5 heat range which would be way too hot to use on a Lycoming. Typically use 8s which are 3 heat ranges cooler.

I saw that too. Although "long reach", they are recessed into the head due to the adapters. Perhaps enough local quench to keep plug temperatures within limits? I'm spitballing here.

Don, got any used plug photos?
 
Here's a photo of long and short reach plugs we sell along with adapters.



Long plugs are Denso IKH24 Iridium, shorts are standard NGK 3961 which are solid cap BR8ES.

The long plugs are commonly used in IO-390 and IO-580 engines.
 
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