[Shop-talk] Spar plug inserts

[Jeff Scarbrough]

On Mon, Mar 19, 2018 at 5:51 PM, Brian Borgstede <bborgstede at charter.net> wrote:
> All,
> What’s your favorite fix for spark plug threads in aluminum? I’m fairly new to VWs and these plugs aren’t comming out without a fight.  For those not familiar, they are like a lawnmower, same threads and just as short.

Some 40 years ago, we used to use some sort of solid insert; a bushing
with inside and outside threads.  A special tap that had spark plug
threads on the end, then tapered out through a cutting section into
the bushing thread size.  Smear it liberally with grease, and run it
in (make sure the piston is BDC first!).  Not the best repair, but
>>Dealership Approved<<.  I still have the tool, but haven't looked
for the inserts in a long time - I recall they were sort of
hat-shaped, so they didn't go in too far.

I've also seen a Helicoil used - I may have done that, too.

These days, I'd use a locking insert -- a TimeSert or something
similar -- if I was otherwise convinced that he head was in tip-top
shape.  Easy enough to pull the engine and make sure it doesn't have
the cracks between the seats, etc.

Jeff Scarbrough
Corrosion Acres, Ga.