No I do not have these, just found the image. Anyone know about the red top plug?
If the one on the left is a compression tester, why the side electrodes?
Wonder if the Stevens item shows up in a catalogue someone may have?
Aaahhhh, I mean the one on the other left. (right side of image)
I have one of those Stevens plug "tools" and have always wondered what it is and what it is used for.
Erich - You mean your "other left"?
I think you meant your right,.....sorry Erich,....couldn't resist.
Very interesting assortment of unusual plugs, and as usual, excellent pictures. I really, REALLY think that "compression plug" is neat. Not sure how accurate the compression readings would be, but I've always been led to believe that as long as the compression was at least "adequate", the important thing is that there is not too much variation in compression between cylinders. And even if not too accurate, that compression testor plug would certainly indicate any significant "variation" between cylinders. Thanks Erich,...great post,.....harold
Oops,......ya' caught it while I was busy,....giv'n ya' the business Erich! You type faster than I do,.....harold
I was using both of my left hands Harold.
I suspect that the compression tester started out life as a take-apart spark plug with one center electrode and two side electrodes; that was a fairly common arrangement, back in the day. The center, including the center electrode, was removed and replaced by the compression measuring doohickey. The side electrodes no longer have a purpose, but do no harm.
The red top one look like it would do the same as:
Maybe the red top is an early "booster gap" plug to resist fouling?
For some reason, the cool sounding term "spark intensifier" comes to mind!