TORQUE spec'd for spark plugs?...

[fixizin]

Yep, I checked the Tech Lib first, only torque specs listed are for the "important" stuff (head bolts, rod bolts, etc.)...

... finally getting around to doing this @ 92k miles... been procrastinating since 83k miles.

I ask because, strangely, Cylinder #2 plug has broken (the actual electrode, deep down by the hex) TWICE on me over the years, wondering if it was over-torqued at the factory (robot?), then over-torqued by ME when I replaced it the first time?

Thanks in advance!

 

[Li'l Work Truck]

With spark plugs, there's not really a torque setting, because you just seat the spark plug and cinch it. Just a half turn, or until it resists a single-handed turn before you're cranking on it.

 

[bobbywalter]

7-15 ft lb is standard....which is what seats the washer if equipped...high side on re-use

 

[fixizin]

I wonder if my still-shiny mid-1980s Craftsman El-Wrencho-de-Torqo even goes that low... checking... Jeopardy muzak... it DOES!

Now I just gotta get my AutoZone loaner Compression Tester and surprisingly hi-res TEMU borescope sorted out...

... Clear Flooded Engine mode will be getting some use!

 

[bobbywalter]

those cameras are damn handy.....get in there and see whats happening...

 

[Curious Hound]

On the 4.6l I had, it didn't matter. The darn things would back off enough to leak. The pressure blowing back would push the plug wire/boot off and I'd have a mis-fire.

I hated that engine and don't ever want another one.

 

[fixizin]

those cameras are damn handy.....get in there and see whats happening...

Indeed, never done it, can't wait to take a peek at my pistons and cylinder walls... NOT sure if I'm going to attach the tiny mirror attachment, and try to examine the VALVES...

... IF the mirror falls off in the combustion chamber, can I fish it out with the magnet attachment?? Yep, time to rig up a SIMulator... and practice!

 

[RobWigglezz]

My bore scope has an articulated dingus end that will make any woman blush.

I wouldn't worry too much about over tightening spark plugs in cast iron heads. Once it's snugged down you'd have to put an uncomfortable amount of grunting to strip the threads out.

 

[fixizin]

My bore scope has an articulated dingus end that will make any woman blush.

Do they ask to "borrow" it, for "research" purposes?

I wouldn't worry too much about over tightening spark plugs in cast iron heads. Once it's snugged down you'd have to put an uncomfortable amount of grunting to strip the threads out.

I know, right... 15 ft-lbs. seems not nearly enough...? Certainly takes WAY more than that to back them out!

 

[broncc]

Spark plugs are basically just slightly above finger tight. There isn't much harm in them being too loose provided you don't put 10,000 miles on them audibly leaking. I think ford cylinder heads use a taper on the plug to seal, aftermarket use a crush washer.

Some plugs will have a torque spec on the box. I think you don't really want more than 10 ftlbs. Don't use a 1/2" torque wrench with the torque right at the end of the range, get a smaller one with 10 in the middle.

Airflow Research states in their aluminum cylinder head instructions to ignore all suggested torque specs and gently bottom out the plug.

 

[RobWigglezz]

Spark plugs are basically just slightly above finger tight. There isn't much harm in them being too loose provided you don't put 10,000 miles on them audibly leaking. I think ford cylinder heads use a taper on the plug to seal, aftermarket use a crush washer.

Some plugs will have a torque spec on the box. I think you don't really want more than 10 ftlbs. Don't use a 1/2" torque wrench with the torque right at the end of the range, get a smaller one with 10 in the middle.

Airflow Research states in their aluminum cylinder head instructions to ignore all suggested torque specs and gently bottom out the plug.

Around 2016 I bought a '99 2.3l from my neighbor across the street. It had an annoying exhaust leak that I put off fixing for 2 weeks. Well, turns out 2 spark plugs were loose which also made it drive way better.