Stripped Spark-plug

[AlwaysL8]

...hey guy's...ummm...and gal's. *s*


       ...it seems I'v removed a (thread insert) [--- ?
  while removing a spark-plug in my 1600 VW/AC engine.
   What happened was...I was getting a noise..(not gonna try and spell it)...and traced it to a cylinder. The spark-boot, had been melted to the point, it fell off the plug. Soooooooo...I removed the plug to find that it came out....NOT with a heli-coil thread on it...but an actual threaded (inner/outer) collar wrapped around it. :-(

         It is a collar of some type for sure...comes with a small shoulder and all. And about a heavey 1/16 or 3/32's thick.

      There was blow-by, and it cut/blew a path right through the threads of the collar....not on the inside...(spark-plug side)...but on the out-side...between the collar and the cylinder- head....
 I guess what I'm wondering...is....ummmmm...anyone else have this happen...and will I be replacing a cylinder more so then just installing a new \"collar\" ?


                          Thanks in advance to all who can help.


                                                                       Always L8

[Cameron]

     
      There was blow-by, and it cut/blew a path right through the threads of the collar....not on the inside...(spark-plug side)...but on the out-side...between the collar and the cylinder- head....
 I guess what I'm wondering...is....ummmmm...anyone else have this happen...and will I be replacing a cylinder more so then just installing a new "collar" ?


 

I've seen this happen before. Once you blow out that type of insert (Timesert brand?), you're \"F\"ed. You have to pull the head off , have the hole welded up, and re-cut the threads. And there may be lots of welding and seat replacement nessesary, if you have burned through to the valve seat. If there is nothing special about the cylinder head, it would probably be faster and cheaper, to just buy a new head, or good rebuilt head.  

[AlwaysL8]

        ....thanks Cameron.      I appreciate the feed-back.

            From what your saying...I need a new/used head....nothing special about mine..(stock)

        I recently purchased the (idiot book) by John Muir....I'm hoping....hopefully I can fix the problem before next april/may as I live in Canada. Not alot of pix in the book...but seems to go step-by-step...hopefully I'll prevail.

          Again thanks  



                                                                     AlwaysL8

[Matt]

I am assuming you have a dual port motor, but if it is single port, I have a pair of good heads here.  

[moni]

I recently purchased the (idiot book) by John Muir

the idiot book is good, but i highly recommend getting a second book to cross reference. i found the idiot book a bit lacking in some areas; and having another manual to translate what the hell muir was talking about very handy. if you can get your hands on the hanson engine rebuild book, there's LOTS of pictures. good luck with the project, and make sure to post any and all questions you have on the forums. when i did my rebuild, the folks around here were great!    

[Scratchy]

I \"rethreaded\" the sparkplug holes in my heads during a rebuild with a 1/2' copper pipe adapter.
It was threaded with 1/2\" NPT on the outside with a hex collar and then 1/2\" copper female solder joint on the rest.
I drilled and tapped the head with a 1/2\" NPT. I scored the pipe adapter just below the hex collar so it would snap off once I screwed it in place
and peened over the copper on the inside of the combustion chamber. I cleaned up the copper sticking out past the spark plug seating surface a bit with a chisel. Then I just tapped the copper insert with a 14x 1.5 mm tap. It held up for 5000Km so far....

The thing to remember when removing spark plugs is NEVER remove them on a hot engine. Wait until the head is stone cold before attempting to remove the sparkplug, or you are asking for trouble. Aluminium galls very easily, and more so when it's warm/hot.

Art

[Cameron]

Then I just tapped the copper insert with a 14x 1.5 mm tap.

M14 x 1.5 ??

[moni]

if you can get your hands on the hanson engine rebuild book...

correction, cos i'm a dumbass: i meant the chilton rebuild book.  :blush:  

[Scratchy]

M14 x 1.5 ??

My bad, 14x1.25mm
Same size as the 4 bolt wheel studs.....