[Shop-talk] Spar plug inserts

[Randall]

> Back in the 70's I used helicoils on vw spark plug holes with fair
results.
> Each one I installed worked fine but from time to time when I pulled out a
> spark plug the helicoil came out with the plug. Some that came out were
> done by other shops & a few of mine.  I seem to recall using anti-seize on
> the plugs. I suspect there are better choices today, something with a
lock.

Ditto, except on outboard motors; and none of mine came out once I started
using high-temp high-strength Loctite on the insert, and lots of anti-seize
on the plugs.

Also make sure the plug doesn't extend into the combustion chamber.  I can't
recall the details now, but there was some engine that came in two different
versions and I had the "heavy duty" version that took 1/2" reach plugs
instead of 3/4" reach.  Wasn't an outboard though, might have been my old
motorhome.

-- Randall