best way to clean the crud off a spark plug? cabinet blaster?
That will work, but don't use anything as abrasive as sand. You don't want to wreck the smooth surface of the porcelain. With X's, you can take out the porcelain and just clean the metal parts.
Get one of those spark plug cleaner/blasters. We have one at the shop, does a quick job cleaning them up. I wire wheel the heavy crud off first.
If you are cleaning take apart original style plugs you can clean the porcelain with comet or zud cleanser and water. These cleansers are made to clean porcelain sinks and tubs and work very well on the spark plugs. If the carbon buildup is heavy I use the cleanser and scotch-brite pads to scrub them clean. I use a round brush with cleanser on the metal housing.
I turn the plug upside down and fill it with brake cleaner. I let it sit for awhile and most of the carbon crud comes off.
I use a bit of Scotchbrite and some WD40 to clean plugs after I take them apart.
A wire wheel can ruin a spark plug. Learned that the hard way. This was on a plug that had no glazing on the inner porcelain part. Bit's of the wire wheel embedded into the porous porcelain (Say that 10 times real fast) and it mis-fired like you wouldn't believe.
On the inside porcelain surface you are looking for as smooth and polished surface as possible. I sometimes glass bead them or just polish by hand. I would not use any kind of sand or rough abrasive on the porcelain. The metal parts would be OK to sandblast or glass bead. If not wanting to take the plug apart I would use nothing more abrasive than glass beads. Soda blasting or walnut hulls should be OK also. If taking the plugs apart be very carefull with the mica washers as they are hard to come by if you ruin them.
I wash 'em out with lacquer thinner. Seems to work well, but so far I really haven't had plugs come out too gunky. Usually #1 is the dirtiest for some reason-anyone know why? That one sometimes I soak a little, but usually doesn't need much.
" Usually #1 is the dirtiest for some reason-anyone know why?"
It runs cooler than the others.
Efferdent I have heard works.
I use a propane torch. Works great.
I had a couple modern Cj8's that were gunky and I have left them in the ultra sonic cleaner for a couple weeks and they get a good shaking and soaking every time I clean a carburetor. Not worth the effort on those plugs but a good experiment and if it fails not much lost.
It cleans some ok, some dont clean up at all.
I have never understood why plugs cant be cleaned by a chemical of some sort. Chemicals clean grease and gunk from the block and such if hot tanked.