Weird thing when hand torquing new Uninstalled Spark Plugs vs Reinstalling it

[taiyou]

Don't bother reading my thread below; I will make my question simple:
Why does it only take 11 and 1/2 turn to finger tight NEW Uninstalled Plug vs 12 turns on used/already installed Plug? I tested on all 4 of the plugs to make sure it wasn't a fluke.




I know it's not difficult to change spark plugs, but it took me 3 hours and I still don't think it's at the right torque, even though it's running fine. I don't have a torque wrench, and I'm using NGK BKR5E-11 V-Power Plug(w/gasket) on KA24DE.
Reason why it took so long is that I discovered something new to myself, and I cannot find any threads about this so here it goes:

I finger-tightened the newly FRESH UNINSTALLED plug, then 1/2 turn hand torque was very smooth(felt like crushing the oil drain plug crush washer).
Then I took it out for some reason and finger-tightened but the 2nd time I tried to 1/2 turn, it was pretty stiff.

So on my 2nd new UNINSTALLED plug, I counted how many turns it takes to get it finger-tight. It was 11 and 1/2 turn. Then I did 1/2 turn hand torque; took it out, and it took 12 turns to get it finger tight the 2nd time! If you do the math, 12 turns should be right because you add 11.5 and .5=12, but this confuses me now!

So I'm not really sure if you still have to hand torque 1/2 turn on already installed/used plug?? If I were to use Torque wrench the 2nd time, wouldn't it double the torque spec? I hope this makes sense. Please help me out.

[breakindrifts]

wtf. just tighten the bitches.

why make it complicated?

[aznpoopy]

you guys got alot of time on your hands in california

if you're worried about getting torque spec right use a torque wrench. its 14-22 ft/lbs fyi

if you're normal like most people just hand tighten and leave it instead of beating the shit out of yourself over spark plugs

[camppain]

LOL don't forget to use Anti-seize also.

As stated above, just tighten them down. German torque is good, Goodandtight!

[jackjack]

Originally Posted by breakindrifts

wtf. just tighten the bitches.

why make it complicated?

exactly. some plugs go in smoother than others. you're thinking about it too much. just swap them in and go drive already

[Chrischeezer]

WOW... if ur thinking about stupid stuff like this, your going to drive yourself crazy in the near future.. good lunk

[jilo]

tighten hard, done.

[stinky_180]

your thinking about this too much

[fliprayzin240sx]

Well, unless you already crossthreaded them bitches already...

[taiyou]

I didn't cross-thread. I tested the 12 turns thing many times to make sure it wasn't a fluke. I'm a bit concerned because I don't want to cross-thread it. So when you RE-INSTALL plugs, hand-tight is enough? Or just force the damn thing 1/2 turn again even if it's super stiff? I don't care if it's not perfectly torqued, but I thought someone had the answer to this weird problem. I know most don't care, but I bet 9 out of 10 people didn't know about this

[B Love]

Just get then tight and snug and your fine.

[bongnak]

what you're experiencing is the compression of new washers. ngk have crush washers; when you tighten them for the first time they will feel tight and continue until its fully compressed.
Get it?

11.5 turns+ .5 turn= 12 turns on second install of same plug.... hahah .5 being the washers loss of thickness after first compression

hahaha all good tho kinda funny dont worry about it, but I knew a guy who had a spark plug punch through the hood on his s14 sr

[taiyou]

Originally Posted by bongnak

what you're experiencing is the compression of new washers. ngk have crush washers; when you tighten them for the first time they will feel tight and continue until its fully compressed.
Get it?

11.5 turns+ .5 turn= 12 turns on second install of same plug.... hahah .5 being the washers loss of thickness after first compression

hahaha all good tho kinda funny dont worry about it, but I knew a guy who had a spark plug punch through the hood on his s14 sr

Ok, so for the final question, would you still hand torque 1/2 turn like you're supposed to on the 2nd re-install or leave it finger tight? And thanks for actually posting some helpful information.

[bongnak]

finger tight? never!- just torque it to the manufactuers spec-

[SILEIGHTY_DET]

one grunt with a 3/8 drive wrench . not two grunts , just one . good luck

[EJ253]

the reason you get another half of a turn with used plugs is simple.

the gaskets are already squished.
new plugs have fresh gaskets.