SPARK PLUG REMOVAL & INSTALLATION

  After the normal service life of a spark plug, one or more of the plugs may be a little difficult to loosen. Allowing the engine ample cool-down time will facilitate plug removal. The use of penetrating oil is also recommended if the plug appears to be dangerously tight. Apply steady pressure with a plug wrench until the plug loosens. Before removing the plug, blow any dirt from the port area that might be present to prevent it from falling into the combustion chamber. If the plug appeared to be overly tight when removed by hand, it may be due to carbon collection in the threaded area of the cylinder head. This condition is common in older engines. ( In other words, if you can't re-install the sparkplug by "hand" threading the sparkplug down to it's seat or gasket, the threads are full of carbon or damaged.)  The threads should be cleaned with a chaser tool, and the seat wiped clean to assure good seat contact before installing a new plug.

Note: Use the  torque recommendation below as a guide for tightening all spark plugs.
Always check your engine manual for special sparkplug installation procedures.

Warning: The information below should be used with care. Read it all, Read it carefully. The specification for tightening without a torque wrench needs to be done precisely as shown.

         TAPERED SEAT PLUGS                                 GASKET TYPE PLUGS
plug-torq.gif (3633 bytes)

Finger Tight Install the new plug finger tight, and complete the installation with a plug wrench.

Turn Finger Tight A tapered seat plug does not use gaskets and requires about one-sixteenth (1/16) turn.

Turn Finger Tight A new or reinstalled plug with a new gasket will require 3/8-5/8 turn to effect a gas tight seal depending on head material. (See below.)

1/4 Turn Finger Tight  For reinstalled plugs with used gasket, ONLY a 1/4 turn is required for gas tight seal for both cast iron and aluminum.


TORQUE RECOMMENDATIONS

      CAST-IRON-HEADS     ALUMINUM-HEADS
SPARKPLUG
  THREAD
    SIZE
GASKET PART NO. *     WITH  TORQUE WRENCH WITHOUT TORQUE WRENCH     WITH  TORQUE  WRENCH WITHOUT  TORQUE  WRENCH
GASKET  TYPE PLUG   ** (see note below)
10mm Y678  8-12 lb.ft.   1/4Turn  8-12 lb.ft.   1/4 Turn
12mm  P678  10-18 lb.ft. 1/4Turn  10-18 lb.ft. 1/4 Turn
14mm  N678  26-30 lb.ft. 1/2 to 5/8 Turn 18-22 lb.ft 3/8 to 1/2 Turn
18mm  A678  32-38 lb.ft. 1/2 to 5/8 turn 28-34 lb.ft 3/8 to 1/2 Turn
7/8"     A478  50-55 lb.ft. 1/2 to 5/8 turn -- --
TAPERED
SEAT
14mm  --   7-15 lb.ft.   1/16 Turn (Snug)   7-15 lb.ft 1/16 Turn (Snug)
18mm  --   15-20 lb.ft. 1/16 Turn (Snug) 15-20 lb.ft 1/16 Turn (Snug)
** Torque recommendations are for new gaskets.
* Champion Spark plug part number

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