Spark plugs io390 with P Mag

[bradfp]

Anybody know of a long reach automotive spark plug for the IO-390 that’s the standard nickel; NOT iridium, platinum or unobtainium?

[dmattmul]

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

[bjdecker]

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

Always a good idea to check the source -- see https://www.lycoming.com/sites/defau...%2520Plugs.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.

[RicoB]

Originally Posted by calpilot

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

What or where do you see the difference by running the 9ES instead of the 8ES?
Can someone school me about the 8's and 9's ? thanks
I run the 8's on mine.

[dmattmul]

Originally Posted by dmattmul

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

Reviewed logs on Savoy, RPM drop with SRP and SR adapter previous 10 flights was 50 - 60 RPM. With LRP and LR adapters today was 20. Worth the effort to go to these. Test flight today engine was very smooth.

[glider_rider]

Originally Posted by bjdecker

Always a good idea to check the source -- see https://www.lycoming.com/sites/defau...%2520Plugs.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?

[JHartline]

Originally Posted by glider_rider

Mine IO-390 EXP119 was delivered from Lycoming with Denso IKH27. Do I understand correctly that I should be using different spark plugs?

Denso IKH27 (5347) plugs are long reach. Expensive, but they are LR.