Spark plugs io390 with P Mag

[DougZetting]

What spark plugs are people using in the IO 390 with P Mags?

[Tom023]

Mine came with Denso IKH27’s.

[Nova RV]

The Denso IKH27 is also known as the Denso 5347. Rock Auto has them for $7.98 Sparkplugs.com has them too @ $10.74

[Bavafa]

Denso Denso 5347 IKH27 which comes with a solid terminal. There are other Denso IKH27 which comes with the screw type terminal which is less preferred.

[DougZetting]

Awesome, thank you all.

[Raymo]

There is no need to run Iridium plugs. Most are using NGK BR8ES (3XXX) and changing them every 100 hrs / annual for about $2.50 ea.

Another reason for replacing every 100 hrs / annual is that you'll have a tough time re-installing them in the adapter (if not impossible) after cleaning, and cleaning Iridium plugs is not the same as cleaning the old massive plugs.

If your cylinders are made such that you don't require the adapter, running Iridium might make sense.

[Carl Froehlich]

Originally Posted by Raymo

There is no need to run Iridium plugs. Most are using NGK BR8ES (3XXX) and changing them every 100 hrs / annual for about $2.50 ea. SNIP

The IO-390 (like other angle head Lycoming engines) needs long reach plugs (like the IKH-26). The BR8ES is short reach, for parallel valve Lycoming engines.

Carl

[bmarvel]

Originally Posted by Carl Froehlich

The IO-390 (like other angle head Lycoming engines) needs long reach plugs (like the IKH-26). The BR8ES is short reach, for parallel valve Lycoming engines.

Carl

Just as a heads up to everyone, I've been using the short reach BR8ES plugs now for several years and 715 hours in the long reach adapters in my IO-390 and have had no problems whatever.

I just received a second P-Mag to replace the impulse-coupled Slick mag I have on the other side and plan to use these plugs in both of them.

I am aware there may be a hypothetical risk of pre-ignition from a glowing particle residing on the lower threads of the long adapter when short plugs are used, but I've never experienced it. Although I fly mostly at high altitudes here in the west, I've routinely operated everywhere from sea level to 18,000 feet and see no reason not to use the less expensive plugs and replace them every year.

[calpilot]

i USE A COOLER PLUG, NGK BR9ES, WORKS GREAT!

[Cwood2000]

Originally Posted by DougZetting

What spark plugs are people using in the IO 390 with P Mags?

I have used the Denso KH27 and switched to the NGK 6240, both are Kryptonite impregnated etc from their marketing departments. Seriously, no issues with either one. I would stick with a long reach plug.