[T3] Spark plug blown out of #4 cylinder
Jim Adney
jadney at vwtype3.org
Mon Jul 18 20:41:33 PDT 2011
On 18 Jul 2011 at 21:16, crash 69 wrote:
> In talking with experienced folks, I've been told TimeSerts are better than
> Helicoil. I've never used them myself. Any opinions out there?
The one thing that I don't like about the solid inserts is that they
tend to come out again each time you remove the spark plugs. The
TimeSerts are better, because the nose gets swaged into the head,
making backout much less likely. OTOH, this swaging operation puts
the alum around the chamber side of the head under tension, in a
place where the heads tend to crack anyway.
HeliCoils have a couple advantages. One is that they spring outward
and tend to lock themselves in position, but over their full length
and not with excessive force. The other is that they leave the
seating face where the plug comes to rest untouched. Both of these
minimize changes in the thermal path from the plug to the head.
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Jim Adney, jadney at vwtype3.org
Madison, Wisconsin, USA
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