Can we talk about torquing spark plugs by feel?

I always thought torque wrenches on spark plugs were overkill, just another way to sell tools... but after I had a plug back out on a Cessna 172 last month, I'm second guessing myself. The old guy who trained me said he'd been doing it by hand for 30 years with no issues, but the service manual says 30 ft-lbs is the number. What side do you fall on, torque wrench or feel?

2 comments

2 Comments

zara_hunt1mo ago

Actually torque wrenches can drift out of calibration over time, so hand feel might be more consistent.

bailey.sam1mo ago

Zara's dead right about calibration drift, my cheap Harbor Freight wrench was off by nearly 5 ft-lbs last time I checked it against a known good one. I've been going by feel ever since and haven't had a plug come loose yet.