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Hank Helmen,     Ruckersville, VA    hhelmen@Aol.com        Started 6/4/2005

Info on the engine:   1936 Popular Mechanics Magazine article.  All patterns and castings home made in my shop.  1-1/4" bore

Runs best on regular gasoline.  Old fashioned points and coil ignition with 3 AA sized NiCd batteries supplying 3.6 volts.  Cam was made using Bob Shores' Cam Cat off-set turning device. The cylinder head was turned from a 2"  chunk of CRS steel bar!  Next time I will use 12L14.  The head, and crank case halves are cast aluminum.  Timer frame and carburetor tube are cast brass.  The hardest part of the build was getting the valves to seat properly.   

9/16/2010

 I finally got my 1936 "MIDGET" engine to run, after making a new cylinder head two new valves, a new valve lapping tool, and a new cam!  Still would not run until I figured out that it runs clockwise, unlike most engine today. 

When trying to get it to run I looked back at the original magazine article and it showed a picture of a guy with the starting rope wound around the flywheel for a clockwise start/pull, so I tried it.. and it worked.  Made a short video today of me and the kids playing with it.  I will enclose the video and some pictures for you. 

I still have some tweaking to do on the exact valve timing or maybe it's the intake.  After one choke it starts right up on regular gasoline. 

  This is the engine made by using Popular Mechanics magazine plans.  It is supposed to be 1 1/4" bore mine is way oversized the make-shift boring tool made gouges half way down the bore when I was cutting it, so I used a brake hone for a long time to smooth them out.  Measures about 1.312 or so now! 

Can't thank Dale and Bob enough for all the kind help on the cam timing.  The two hardest things are getting the valves to seat properly and getting the cam timing correct.   The cylinder head is kind of awkward to machine  because of the big boss sticking up on top.   

Most of the work of making the patterns and casting was done several years ago, Bob V gave me lots of good advise on making those also.

 It has a pretty cool sound to it, very slow running with the big cast iron flywheel. 

video of the running engine

 Hank


 

 

6/4/2005

Here are some pictures of patterns for my latest "Work in Progress"  project.   The engine is a 1-1/4" bore, four stroke single called the "Midget" from a 1938 Popular Mechanics magazine article.
 

 I spotted one of these engines at the "Iron Fever" show in York PA back in 2004.   I could not identify it at that time.  Then several months later I bought some "model engine plans"     --  "really works"   from an  ebay auction.  When I got the plans I recognized the engine right away.  The one I saw was owned by Todd Snouffer's son and he had it partially disassembled at the show.  Apparently he bought it at a flea market many years ago for $60.00 or so.  Tood said that he actually had his running some years ago.

 
I made the split pattern for the cylinder out of mahogany.  The crank case pattern is made from  2X4" pine.   This pattern is probalby the most complicated wood working I have ever done. I had to use the Lathe, the  Mill , and the table saw, and band saw!     There are lots of angles to watch considering  correct draft for pulling the pattern out of the sand.   The other patterns to be made are the 4-1/2" flywheel and the carburator/ intake manifold

 

7/9/2005 update


This is a picture of the 4-3/4"  flywheel pattern in the making.  It is made of two pieces of 3/4" plywood.


Here is a picture of the back and front crank case patterns for the 1938 "Midget" engine.

7/11/2005
 

 

Picture of the engine castings stacked in "assembly" with an original drawing from the article in the background.

 
 

 

A picture of the Cylinder head test casting and its pattern.   Pattern needs some tweaking.
 

 

 

This is the second Cast Iron flywheel and the plywood pattern for it,  The first pour did not go well, My home made sand mix was too wet.
 

 

 

Here is a picture of all the parts and patterns so far. Upper right is a crank case back half in the mold.

  12/2/2005

Here are couple of pictures of my latest work on the Midget engine.   I cast the carburetor/intake in brass today along with the timer frame.  The pattern for the timer was hardly dry when I stuck it in the sand~!   For a first pour on these patterns they came pretty good.
 

I have machined the Cylinder fins, the connecting rod is finished and the piston is complete except for the rings.   I have started machining the cylinder head. It is marked out but I the valve cages and exhaust and inlet holes are not drilled yet.  You can see the cam blank in one of the pictures.  I will use Bob Shores Cam Cat fixture to create the cams.

 

Click here to see more about how Hank makes his castings at home.

 

Copyright 2005,  Florida Association of Model Engineers and engine builder as noted above, All rights reserved.