On 8/2/2018 1:44 AM, Arlen Holder wrote:
On 1 Aug 2018 23:30:57 GMT, Steve W. wrote:
Same threads as a spark plug. The easy repair is a plug rethread kit. It
has an oversized insert with a self guiding fluted cutter/tap
combination. Then you trim the threads on an insert so they don't block
the sensor tip. Screw it into place and screw in the sensor. About the
third time you drive the car that insert will become a permanent part of
the manifold.
Very common repair, done all the time.
Thanks for confirming it's the same threads as a spark plug, which, at the
moment, seem to be 18x1.5 for them.
Googling, it seems cast iron isn't easy to weld, and that the plug rethread
might work, but, the heat cycling has likely hardened the bung nut, such
that it's a LOT harder (some say) to deal with than a spark plug thread
which is typically in aluminum engine blocks (they say).
Searching for this "plug rethread kit", is this the $62 kit you speak of?
https://www.amazon.com/Thread-Kits-1.../dp/B0025PQITU
Â**NO*!! That kit uses standard helicoil inserts , which are fine if
you're using spark plugs that use a crush washer to seal .Â* What you
want is similar to one I have and have used , mine is a NAPA auto parts
#770-3223 "Sav-A-Thread" kitÂ* - it's for 14 mm plugs but you need the
one for 18mm plugs . For the heat cycle hardened threaded bung you need
to heat it red hot with a torch and let it cool slowly - even if (and it
has) the steel has absorbed carbon from the exhaust gasses the slow cool
will anneal the metal (will help a great deal if the manifold is hot too
....) . If you can cut it with a file , this kit will work . One
suggestion - drill the hole out enough to clean up the old threads plus
a bit , it makes the ream/tap operation much easier . This kit includes
a punch that upsets the top edge of the insert (solid metal insert)
knurling into the threads to keep it from backing out . This kit is made
by helicoil , you may be able to find it at another retailer - I bought
another from O'Reilly Auto Parts because this one was "lost" in the move
when I left Memphis for rural Arkansas .Â* I've used these kits twice ,
in 2 different vehicles with excellent results . Both were "hemi" type
OHC motors with the spark plug straight down the center of the valve
covers . Both required machining guide bushings to be sure I got the
hole straight (I have a machine shop , it's a "hobby") and both have run
for many thousands of miles trouble-free . Good luck !
--
Snag
Yes , I'm old
and crochety .
Get off my lawn !