Elf "Pipe" Twin


Name Elf 20 Series 2 Designer Dan Calkin
Type Horizontally opposed, two cylinder, side-port, spark ignition engine Capacity 2.4 cc
Production Run unknown Country of Origin USA
Photo by Ron C Year of manufacture 1940's



The Elf series of engines were produced by Dan Calkin in Portland Oregon from the late 1930's through to the early 1950's. During this time they underwent evolution from side port, spark ignition, to reed valve glow plug while reatining the same basic, modular component design. The engine pictured here is the first twin cylinder version to be produced in any quantity (although all Elfs were essentially hand made, low volume engines). The story of Calkin and his Elfs is wonderfully told and illustrated in the book surprisingly titled Dan Calkin and his Elfs (he never called them Elves) by Bill Brown. The engine shown here is in Tim Dannel's Model Museum collection.

Here is another example, Ser No 462 (which Brown's book lists as first sold in 1946), now residing in my own humble collection. Note that in comparison the the Model Museum engine, this one deos not, and never has had an integral tank (note also the horizontal orientation of the air-cleaner this arrangement affords). It came to me in the origonal box, but without papers and while it may have been run, it has had almost no use.

Closer inspection shows that the arrangement of the intake on this example is probably not original. The air-filter housing appears to have been unsoldered from the inlet pipe, rotated 90 degrees to face backwards, and resoldered so the inlet pipe closes off the hole in the side of said filter. The tank-top has been disgarded and the fuel line (the end of which also forms the jet) has been simply cut off where it bent down to enter the tank. Compare with the rear shot of the Model Museum engine and it should all become plain. The solder job is good, so it's remotely possible this was a factory job, but Brown's highly detailed book makes no mention of any inlets arranged like this. The photo here clearly shows the serial number and the unusual serif font used by Calkin to stamp his engines. If your serial number don't look like this, it's a fake! Also visible is the original piano wire, "low friction, wiper" style timer. Some critics don't like this, but it is well designed, robust, has enclosed points and would have had a low cost to manafacture. The engine is also missing the timer arm (which should mount to the lug visible in the lower right). I will correct and restore these to original, when the time is right.




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