I have a high comp. head that has had all four plugs broken to the point where nothing sticks out of the top.
Any recommendations on how to remove the remaining parts of the plugs?
I would knock out what is left of the porcelain center, place a 3/8 of 1/2 cap screw in the hole and carefully weld it to the plug base. The weld will not stick to the cast.
If you can get all of the porcelain out, just heat the remainder of the plugs red hot and then walk away for a while and let them cool completely. After they are completely cool, they will most likely screw out with your fingers, or at least with little effort. Dave
Nothing on these are screwing out with any fingers. NOTHING remains above the hole. All that is in the holes is the plugs original threaded part. Not even anything to put a wrench on.
As David said heat it up and them let it cool. Then use an easy out and the threaded part should unscrew. The easy out is a tool that turns counter clock wise and has a spiral thread that is tapered. It will bite in and spin out the reaming material of the plug. Scott
you didn't say if its aluminum or iron. i'm gonna guess aluminum if its high compression. either way i'm with dave, weld a bolt inside, and if aluminum let it cool completely so it wont gall on the way out. could even soak a bit after you weld. the heat will make it expand, and the cool down will shrink to give you some clearance
Here is a picture of another "high head"
Dennis, that one looks beyond repair. I would try using a wrench on it anyway though.
If an aluminumn head I do not recommend welding to the remaining threads. You may melt the head if not extreamly carefull. If it is a cast iron high compression "low head" the heat and ez-out techinque should work. Post a few pics of the head and it will help us give you a better solution ...
I like a straight easy-out rather than the spiral type, which can twist in and expand the piece you're trying to remove.
William, try doing what I said, you may be pleasantly surprised. By heating them red hot, two things happen. First, the heat breaks down the rust into a powder, then when they cool, they shrink considerably, loosening up in the hole. Some penetrating oil will help to flush out the powder, but probably won't be necessary. An easy out may help just to give you something to turn with, but I still think they will turn out by hand. Dave
William, have you had any luck yet? Dave
If the head is off, thread a 9/16-18 bolt with a stop nut on it from the inside. It only has to turn very little to loosen since it's a pipe thread. Should come out easy once the rust is broken. From the inside clockwise is loosen.
I haven't messed with it yet. Need motivation. It's just an extra head I have lying around.
I have the 1/2" pipe thread tap if you need to chase the threads after removing the offending part.
I believe any 1/2-14 NPT tapered tap will work for a model T, but be aware there are two !/2 -14 tapered pipe taps. The one for spark plugs is 1/2-14 NPTF that does not require a sealant or Teflon as does the NPT tap. I am offering this as general information.---Len
There is also a 1/2-14 NPS tap, national pipe straight, you don't want to use one of them.
NPT is the tapered one.
Remember you are not cutting new threads, just cleaning the old ones up.