Can we talk about how I used to torque spark plugs by feel and now I actually read the manual

Had a Cessna 172 throw a plug after 50 hours last spring because I was guessing on the FT-LBS, so now I check every spec for that specific engine before I even touch a wrench - has anyone else switched to factory numbers after a close call like that?

2 comments

2 Comments

brian30319d ago

Wait, you threw a plug on a 172? That's insane. I always figured those Lycomings were bulletproof if you just snugged them up good with a ratchet. How far off were you on the torque guess that it actually vibrated out?

faith_perez19d ago

@brian303 You know what, I used to be that guy too (like, I thought finger tight plus a grunt was good enough). Then a buddy of mine lost a plug on a 172 a few years back doing pattern work, same thing you're describing. He guessed at the torque and that sucker worked itself loose after maybe 20 hours. Now I'm a total convert to using a torque wrench every single time (even for oil filters). That experience basically changed my whole approach.