Need some info on high compression (Fred) Head

Discussion in 'Performance Mods' started by Waxxumus, Dec 15, 2015.

  1. Waxxumus

    Waxxumus Member

    1) Is the recommended torque of the spark plug still the same as what the factory recommends?
    (18 - 21 ft.- lbs)

    2) Is the recommended torque of the head bolts any different than a stock head?

    3) should anything be applied to the head gasket before installing the head?

    4) loctite loctite loctite

  2. butre

    butre Well-Known Member

    you don't have to crank down much on the spark plug to get it to seal. I generally recommend finger tight plus a quarter turn or so. the head bolts should be finger tight in the case, and then backed off a full turn, and then around 180 inch pounds for the nuts on top. don't use loctite on those nuts, but go ahead and use it for the studs in the case. what happens if you loctite the nuts is that when the studs stretch and you go to tighten down, the nuts won't spin on the studs but the studs will spin into the case and blow some metal out of the bottom of those blind holes.
    Steve Best likes this.
  3. Waxxumus

    Waxxumus Member

    Im using high quality allen keyed studs with no need for nuts.
    Will these eventually stretch even though theyre higher quality than stock?
  4. Waxxumus

    Waxxumus Member

    and, why would they recommend a minimum torque of 18 ft lbs on the ngk website if they meant you could put it in with 10 ft lbs?
    Are these guidelines? or tolerances found by the manufacturer to provide the best performance?
  5. Waxxumus

    Waxxumus Member

    Its funny it says basically the same thing on the website.

    " using a torque wrench, tighten the spark plug to approximately 7 to 15 lb. ft. for 14mm threads and 15 to 20 lb. ft. for 18mm threads to ensure a gastight seal. Overtightening a spark plug will stretch the plug body and potentially result in breakage upon removal.

    For gasket-type plugs, install the plug until finger-tight. Then if the plug is being installed with a new gasket, use a spark plug wrench to apply a 3/8 to 5/8 turn – depending on head material. (See chart below.) When reinstalling a used spark plug with a used gasket, only ¼ turn is necessary, regardless of head material."

    Everybody says something different, and ive ridden around with only about 5-7 ft lbs on the spark plug.
    But after it leaking once, i never really wanted to take a chance and would use a torque wrench to put them on @ about 13-18 ft lbs. (As the ngk site reccomends)