DougZetting
Member
What spark plugs are people using in the IO 390 with P Mags?
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
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.What spark plugs are people using in the IO 390 with P Mags?
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
i USE A COOLER PLUG, NGK BR9ES, WORKS GREAT!
IO390 angle valve engine (450 hrs.), from the beginning I have been using short reach plugs and adapter in my engine. (Requires long reach) Did not realize this was incorrect and just used what was sent to me. (My mistake, 5 years ago I didn't know what I didn't know) After reading a recent thread checked mine next oil change and saw I needed LRP's. 2 friends with similar set-ups also had incorrect adapters and plugs installed. Today replaced with LR adapters and long plugs. When I removed the old adapters, I could see quite a lot of carbon build-up in the threads that were not being used. Used a small vacuum hose down one plug and used a thread chaser to clean them up. PITA, after 2 hours finally had all 8 clean. Most took 5 to 6 tapping and removing and cleaning the chase and reoil. Mag checks produced less RPM drop than before and running on one electronic unit could hardly tell I was only firing on one plug. Have not flown it yet and will check the data on Savoy soon. Results may vary. FYI
Always a good idea to check the source -- see https://www.lycoming.com/sites/default/files/attachments/SI1042AH%20Approved%20Spark%20Plugs.pdf
All of the -390's need long reach plugs, double check the paint markings to be certain. However, not ALL angle valve engines use long reach plugs -- for example IO-360-Axxx, C, D series use REM38E -- short reach plugs.
Mine IO-390 EXP119 was delivered from Lycoming with Denso IKH27. Do I understand correctly that I should be using different spark plugs?