TIL I was torquing spark plugs wrong for 5 years on Pratt & Whitney engines

I always thought you just crank them down till they feel tight, right? Last week a lead mechanic at the DFW hangar caught me and showed me that I was over-torquing them by nearly 15 ft-lbs on the manual gauge. Apparently I missed the memo on using a deflecting beam wrench for those specific plugs in the P&W manual. Has anyone else found hidden torque specs that changed how they do a basic job?

2 comments

2 Comments

julia_lee1mo ago

Damn, 15 ft-lbs off is wild lmao. That's the kind of mistake that could literally crack a housing and you'd never know till it fails.

the_margaret1mo ago

Same thing happened to a buddy of mine last year. He torqued a valve cover to spec on a warm engine and the gasket squished out weird. 15 foot pounds off is the difference between a good seal and a slow weep that shows up six months later. You're right, julia_lee, those little mistakes hide until they don't. Hard lesson to learn but one that sticks.