Torquing spark plugs

Discussion in 'Engine, Fuel and Exhaust' started by lastinline, Apr 8, 2010.

  1. lastinline

    lastinline Member

    I'll quote my HD owners manual...

    "Spark plugs must be tightened to the torque specified for proper heat transfer. Tighten spark plugs tp 11 - 18 ft-lbs per plug."

    I found the same reccomendation on 2 other 'name brand' spark plug web pages. I have tightened my plugs up to what I feel is pretty tight. Well, as tight as I'm comfortable with. When I check it with a torque wrench, ( use 2 different torque wrenches) it still isn't as tight as recommended.

    I'd appreciate any thoughts or opinions on this. I am kinda OCD when it comes to my bike and torques. The plugs are the only thing I'm hesitant on torquing.
  2. Jack Klarich

    Jack Klarich Guest

    I use anti sieze un the threads and go 1/2 turn past tight
  3. glider

    glider Veteran Member

    Follow the manufacturers specs on torquing g the plugs. It aids in heat transfer which is how they come about the proper heat range plugs for the applications. Too loose and the plug runs at a different heat range than it was designed to do.

    BUBBIE Well-Known Member

    I'll agree using the anti seize, It is a must in my book. Those long threads on the plugs need the lube offered and keep them going in and out without damage to the alum. head threads..

    I don't torque my plugs with the t- wrench #. never have, I go with the feel and I'm comfortable they are done to MY specks.

    Jacks way sounds interesting and probably works well, I will try it on my next set I install..

    It may be kind of like the head bolts that i do tighten with a torque then go 90* off that torqued value for the final tightening...

    That(90*) seemed a little different early-on in my mechanical mind but it is what it takes and works...

    thanks for your tip Jack!

  5. oppirs

    oppirs Member

    I didn't know that I just tap my socket wrench with my palm a few times to snug it up and compress the ring. I even run my snowblower & lawnmower just fingertight. But not my cars or bike.

    Am I making my plug run alot hotter?
  6. Jack Klarich

    Jack Klarich Guest

    Glider is 1000 percent right, I have found most man. of plugs to say 1/4 to 1/2 turn past seating, and checking with an inch pound torque wrench that is correct. The plugs have to seal compression, transfer heat and light the fire. The heat transfer is very critical, Jack
  7. lastinline

    lastinline Member

    Thanks for all the replies.

    I always put a film of Permatex Anti-Seize Lube on the plug threads. I was curious about the importance of the heat transfer. And, how many people torqued the plugs to 18 ft-lbs. I got them quite tight with a ratchet... not sure if it is a half turn, but, 18 ft - lbs. can't be much more.

    My girlfriend keeps tellin' me to man up and torque 'em down...
  8. Fossil

    Fossil Active Member

    Keep in mind that when putting in new sparkplugs you are tightening down the crush washers. Theoretically when ever you lossen the plugs you are supposed to replace the crush washers. So, Glider is right on tightening the new spark plugs. Fossil

    NEWHD74FAN Experienced Member Retired Moderators

    Amen Glider and Fossil, new spark plugs come with new washer for a reason, tightening the plug to "crush" the washer ensures you do not overtighten for best heat transfer and seal...especially if you do not use a torque wrench. The good news is if you follow Jack' 1/2 turn after the plug contacts the crush washer you will be very close...just don't reuse that crush washer doing it that way, else the crush washer being already down that 1/2 turn after contact would be too much.
  10. fin_676

    fin_676 Experienced Member Staff Member Moderator Contributor

    Always use the correct torque on the spark plugs or you may end up stripping the threds out of the head if you over tighten if this does happen then if you let me know and bring your bike round ill fix it for you
    as ive got a kit that will replace the threads on a few heads
    I paid a lot for that kit and only used it the once id like to see it all used up