S30 Choke Knob Conundrum

[Namerow]

As near as I can understand it, the conventional wisdom is that there are only two versions of the choke knob for the 240Z:  an early, rounded version and a later, more square-ish version (the knob in the 260Z had a more slender design than either of the 240's, and I guess the fuel-injected 280Z didn't have a choke knob at all).  In all of the many pictures that I've seen of the 240 choke knob, never does the design include the script, 'CHOKE' in addition to the icon.

My small assortment of choke knobs (see photo) includes these three items:

• right - a new, later-style knob
• left - two used-condition knobs of an unknown origin, both of which include both script and icon.

The two mystery items are slightly asymmetric in design, but not to the same extent as the no-script 'round' and.  They each came with identical slot-head set screws that fit nicely into the recess on the leg.  The thread diameter measures as 3.0mm.  However, I don't know whether they actually belong to the mystery knobs or not.

One final note:  The mystery knobs fit well on the metal S30 choke lever in two respects: 1) the slot for the lever is the correct width and depth, and; 2) the set-screw hole in the plastic knob lines up with the set-screw hole in the metal lever.  In a third respect, the fit of the mystery knob is off a bit:  without the set screw in place, they rock a little, fore-aft, when fitted onto the lever.

So:  Does anyone know where these two knobs come from?  They match the known S30 knobs' graphic quite well and the set-screw location is spot-on.  In shape, they seem to be halfway between the 'early' and 'later' S30 designs.  Maybe they came from a Datsun Roadster or a truck?

[Namerow]

OK, I may have found the answer myself.  Eric Neyerlin's excellent ZParts.com site includes a pair of photos that document three different shapes of S30 choke knobs, as well as variations of 'with script' and 'without script' (irrespective of shape).  It looks like my 'mystery' items are actually one of the two different 'shape' versions that were used for the 72-73 Z's.  Probably from the early part of the 1972 run, since their shape is kind of 'in between'. 

If you're interested in more details, go to the ZParts.com site and click on the tab at the top marked, 'ZP TECH'.  Then look for the link, "S30 Parts Comparison Index".  Then search on 'choke knob'.

Eric's notes also document the use of at least three different types of set screws for the S30 choke lever.

This would make a great display collection for the 'driven' 240Z/260Z enthusiast:  a complete set of all the different choke (and hand throttle) knobs used between 1970 and 1974!

[zKars]

Here is Eric's choke know image from his website.   zparts.com/zptech/comparisons

 

[zKars]

My meager collection