Our Featured Rare Find for the month of June 2015 edition is something a bit different.  Some of you may have seen others like it before but did not know much about it, so we thought that we might fill in a few details.


And while not a motometer in the traditional sense and use of the term (even by us), nonetheless this month's device was capable of monitoring an engine's temperature, performance and communicated a message regarding the the engine's operating condition, just as traditional motometers.


The goal of this section is to expose site visitors and motometer collectors to some of the most rare or unique motometers ever created.


The featured items in this section are subject to and will change periodically, so we encourage MotometerCentral website visitors and subscribers to regularly check this site area.


We hope that you enjoy this month's installment.


And, keep your eyes open so that you can find yours!


For a quick information view scroll over the picture/image or to gain a larger/expanded view click on the picture/image.




1945 & 1947




A sub-category of our overall automobilia collection is that of visible spark plugs.  You know, the kind with clear glass housings that enable the spark to be viewed.  Not many spark plug manufacturers made use of this approach.  The month of June 2015 provides the opportunity to showcase a particular engine plug that, apparently, many folks know little about (by their own admission).


Seemingly complicated, this plug was marketed by the Chandler Evans Corporation of (Meridan) West Hartford, Connecticut.  The plug invented in the early 1940s was primarily used by the aviation industry, followed by the boating industry to detect and remove moisture from an engine's cylinder(s).


Innovatively designed using silica-gel in crystal form under a glass upper housing the crystals were multi-chromatic as moisture was absorbed.  A new, unused and fresh plug's crystals started out blue in color and would change to a pink hue as moisture permeated the glass and finally a tan color at full saturation.


The plugs were manufactured to be inexpensive enough that they could be readily discarded after limited use.


The Protek Plug has relevence here as it indicates  a condition of the engine's status, whether in storage, idle, during operational tuning or in maintenance status.



The copper skirt around the plug this plug states "Chandler Evans West Hartford, CT."  Two model versions of this plug were invented, manufactured and sold, the cylindrical and the "reduced neck" type.  They were either 14 or 18 milimeters in thread width dependent on the engine's nation of origin, Britain or the United States of America, respectively.



Chandler Evans Corporation, CECO, made a name for itself through its focus on engine fuel systems primarily for military airplanes.





According to unofficial sources plugs that have a pink color can be restored to original blue color and be re-used.  And, while we are aware of the technique/process recommended, we do not state it here as we have not tested the recommendation for ourselves and without actual successful experience would not want anyone to be injured because the information was either faulty or failed to provide correct safeguards.




Oddly enough, even though this plug was used in the mid 1940s, was a part of the American and British military air service, it was not patented until the early 1950s.



Shown Left are two examples of the 1945 version of the plug.  The tan -to- brown color indicates that the silica gel crystals have absorbed their maximum amount of moisture (probably due to years of incorrect storage) and are neither restorable or usable.  Note the difference in plug shape versus the "reduced neck" version above.  Functionality and purpose was the same for both types.


Additionally note their similar shape to the illustrated ones in the magazine advertisements.



Immediately at Left, the lower end of the plug reveals the moisture entrance aperatures (tiny holes).

Patent Information

Patent Registration Number:





Manufacture Information

Chandler Evans Corporation

West Hartford, Connecticut



Posted: June 2015




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