Spark Plug Problem?

Still working on the 280SE Coup. I did indeed have a dead thermostatic valve on the injection pump. As well as an incorrectly set point. It was barely opening. A couple of tight intake valves but no big deal. runs a bit better, but still not perfect.

I did however, find a fly in the ointment. #6 spark plug, is somewhat stripped out. it will run flush with a little bite but it will spin if you try to put any torque on it. Somewhere along the line it looks like it has been over torqued. The cylinder will fire without a miss but I don't think that will last. How can I correct this problem without removing the head? I don't think it could be tapped and heli-coiled with the head on, the chips would get in the cylinder. Any suggestions?


Mike
61 220 SE
69 280 SE
72 250C

[engatwork]

I have inserted a heli-coil on a stripped out spark plug hole on a Corsica. The secret is to use grease on the tap allow the metal shavings to be removed - they will stick to the grease. Have not heard of any problems from the Corsica owner on this fix.

[Benzmac]

That is the correct procedure. Helicoil makes a specail kit just for this.

That will work! I'll give it a whirl. Most of the heli-coils and taps I have bought just came form my local hardware store. Where can I find a spark plug tap and Heli-coil, better yet on a Sunday?

Thanks,
Mike

Tapped and heli-coiled! all before 10am on a Sunday. I need to give a plug for Clements Hardware in good old Severna Park, MD.
Clements has also a nice stainless metric nut and bolt selection.
They let me borrow a tap kit, sold me a heli-coil for 3 dollars. Work great. I used the grease on the tap and that got must of the chips. Then I took a metal rod bent it about 30 degrees a little grease on the end of that got what ever went into the cylinder head.

Thanks Much,

Mike