I agree with Colin on this point. Aluminum is a soft material and I've had
problems that required Heli Coils but these were only on high stress, high
torque applications. Pulled so many transmission mounting and head to case
bolts on my racing Harley's that it became standard practice to incorporate
the changes in the original build stage of the process. As long as the plug
threads are OK to begin with, and I would certainly have this checked as
most mechanics in the auto industry are paid piece work and eliminate the
anti-seize bit. For my own applications, steel or iron heads I run a thread
chaser thru the holes to remove any and all carbon before installing new
plugs. Aluminum heads require a little more caution as the chaser might have
a tendency to remove metal so in these cases I use a 12 gauge shotgun bore
brush dipped in solvent. In any case NEVER install plugs without a good
quality anti-seize and save yourself grief further down the road.
Doug Rupert
