The short: I'm up and running.
The long:
- The Walton tap extractor has the 4 hardened 'fingers' intended to slide down the flutes thereby allowing you to drive the fingers in the flute to back out the tap. I took the Walton tool apart and, using one finger, probed each flute of the broken end of the tap to see my depth of engagement (its always good to go deep...). I re-assembled the tap extractor leaving out the shallowest finger thereby maximizing the engagement of the remaining three.
- I used a mini propane torch and 'kissed' the cast iron around the broken tap. More like hot bath water than anything. This seemed to expand the surrounding iron just a tad without heading the tap or the valve cover gasket.
- I was lucky...just enough finger engagement to break loose the tap. From that point, it was a game of patience and finger engagement. Every 1/4 to 1/2 turn of the broken tap, I would completely remove the tap extractor, probe for engagement, re-assemble for maximum engagement, and continue. 40 minutes later I had the sucker out!
- Chased the threads with a new tap for clean-up
- Clean female threads of hole and male threads of bolt with acetone
- Epoxy (JB weld) the bolt into place (I used a set screw. My intention was to use the appropriate socked headed cap screw with locking washer, but the diameter of the head interfered with the cast iron of the engine. Not wanting to shave anything from the engine, I bailed to a set screw.)
- Top off the oil, check everything out a third time and start 'er up keeping an eagle eye on the oil pressure gauge.
- Drive out of the back yard and to the local micro brewery
Hind sight:
(1) Patience, patience, patience
(2) Don't break a tap
(3) If you do, there are many ways of removing the broken end. Prioritize them in order of severity then get started (i.e. method 1 should allow for the fall-back to method 2 allowing for the fall back to method 3 etc. In my case, method 1 was pliers. Method 2 was the Walton tap extractor prior to welding a nut or drilling or burning it out)
(4) Prior to using the tap extractor, I should have used an air compressor to blow in some lubricant. In my case, I would have been blowing the lubricant straight into the engine so I would have used engine oil as it was meant to be there in the first place (Caution: don't blow any metal bits into the head...)
(5) Though I did use ample tapping oil, it was generic and there is quite a difference in the performance of generic tapping oil and moly or tap magic, etc. I should have sprung for the good stuff.
(6) Agreeing with HighPlanesDrifter...a velvet touch helps to get the feel for the tap. I did back-out/clean-out every 1/2 turn, but got greedy/impatient/etc. toward the end and snapped the sucker.
As always, thank you all for your suggestions. I hope no one is in this pinch, but if they are, this thread may come of some use. If anyone still has any questions, I'm here all night...
~Humbly, HopLite~
