Register now to get rid of these ads!

Spark plugs--AC 44 vs AC44s

Discussion in 'The Hokey Ass Message Board' started by GARY T., Mar 15, 2014.

  1. GARY T.
    Joined: Mar 23, 2008
    Posts: 1,985

    GARY T.
    Member
    from S.W. Pa

    My engine originally called for AC 44 plugs---Found some nos AC 44s . Whats the difference between a 44 and a 44s,and can I use them?
     
  2. 44S has a tip that extends maybe 1/16 inch deeper into the combustion than a normal 44. As long as you don't have any pop top pistons you should be good to go. The extended tips are supposed to stay cleaner, since the tip is hanging farther out into the fire in the combustion chamber. YMMV.
     
  3. stimpy
    Joined: Apr 16, 2006
    Posts: 3,547

    stimpy

    there 7/8 thread reach vs the 1/2 thread reach , the threads will stick out in the chamber besides the tip being farther out
     
  4. GARY T.
    Joined: Mar 23, 2008
    Posts: 1,985

    GARY T.
    Member
    from S.W. Pa

    NOPE--threads are same length


    Found an old tune-up chart---correct plug for my engine was AC44,BUT said AC44s for light duty (whatever that is) So I'm good to go!
     

  5. Be sure of the thread length. If enough of the threads of the plug extend further than the mating threads of the head into the combustion chamber, they can collect carbon and cause problems removing the spark plugs down the road. :(
     
  6. Engine man
    Joined: Jan 30, 2011
    Posts: 3,480

    Engine man
    Member
    from Wisconsin

    Manufacturers specify a spark plug that puts the spark in the correct place in the combustion chamber. Take advantage of their engineering and use the proper spark plug.
     
  7. GARY T.
    Joined: Mar 23, 2008
    Posts: 1,985

    GARY T.
    Member
    from S.W. Pa

    Yeh,gaping at .035---some say to go more with pertronix,but no need to
     
  8. stimpy
    Joined: Apr 16, 2006
    Posts: 3,547

    stimpy


    only giving info from the manufactuer looked at the chart on the wall ..
     
  9. GARY T.
    Joined: Mar 23, 2008
    Posts: 1,985

    GARY T.
    Member
    from S.W. Pa

    better read it again:eek:
     
  10. stimpy
    Joined: Apr 16, 2006
    Posts: 3,547

    stimpy

    [​IMG]

    same chart on my wall
     
  11. GARY T.
    Joined: Mar 23, 2008
    Posts: 1,985

    GARY T.
    Member
    from S.W. Pa

    I have no idea why the chart has 2 "S designations,but as you can see,these plugs I have are not 7/8" thread----A lot of GM cars used these back in the day---they are not made anymore--notice Made in USA!!

    Dogone it--I took some pics and can't seem to upload them *&^%^&never happened before,But anyway they have about 1/2" of threads and are the same reach as the Autolite 85's that I'm replacing
     
    Last edited: Mar 15, 2014
  12. 40FordGuy
    Joined: Mar 24, 2008
    Posts: 2,907

    40FordGuy
    Member

    44S WILL exactly replace the 44 . As stated, the only difference is the extended tip. We used them in customer cars All thru the 60's, and no issues.

    4TTRUK
     

Share This Page

Register now to get rid of these ads!

Archive

Copyright © 1995-2021 The Jalopy Journal: Steal our stuff, we'll kick your teeth in. Terms of Service. Privacy Policy.

Atomic Industry
Forum software by XenForo™ ©2010-2014 XenForo Ltd.