"Kyle Boatright" wrote:

On Lycoming cylinders, I believe the CHT boss is already drilled and tapped.
I know they were on mine.

KB

There is a pipe like fitting that is screwed into those holes. The CHT probe is
then inserted into the fitting and a BNC like cap compresses a spring that holds
the tip against the head (at least it was that way with the Grand Rapids EIS
that I used). The hole in the cylinder head is not very deep at all. Maybe 3/8
inch. It is really like one of those digital thermometers that you push against
your head inside your ear.

In another application I couldn't use the 14mm spark plug probe since I had 10mm
spark plugs and instead just put it under one of the head nuts on my VW.

CW

"flybynightkarmarepair" wrote in message
oups.com...
How deep is the hole a "bayonet" type CHT probe fits into?

I don't like the spark plug senders, and want to drill the cast-in
boss for a CHT sender to suit the probes commonly available, but
without a probe in hand, I can't tell whether this is possible.

Anybody who can answer this question already knows what they look
like, but this forum serves an educational purpose for people other
than me, hopefully, so here is what I've talking about:
http://buyjpi.com/Merchant2/merchant...tego ry_Code=