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David Kerzel,     Pompano Beach, Florida

Inline CO2 type 4 cylinder compressed air engine  First posted 5/28/2004

This is my fourth small bore CO2 engine.  this one was inspired by some conversations with Steve Peirce about how to handle the exhaust ports on these little engines.  I started sketching and realized the inline design was more compact than the horizontally opposed design. 

I drew up the block and oil pan.  I should have finished the HO4 testing but I had to see how the parts would fit together for this new one.  Normally I design all the parts before I begin to cut metal.

The engine is about 1.275 inch long and will be 3/16 bore and stroke like the last one.

I have no firm plan for what I will do for intake and exhaust manifolds.  If it ends up looking good it might rate electroformed manifolds.


The unique part of this engine is exhaust ports that are hidden and having the exhaust discharged from the head.  The CO2 engines use holes or slots at the bottom of the stroke to release any remaining pressure.  In this engine that exhaust will flow up the small holes to exhaust ports in the head.  The two sections of the head are going to be silver soldered together.


Silver solder disaster.  At home I did not have enough heat, At work I think there was too much.  When I visited Bob Shores 2 weeks ago we discussed the problem.  he told me about how a silver smith taught him how to silver solder.  They rolled the silver very thin, fluxed both parts and heated until it flowed.  I hammered out a thin frame coated the parts with flux, aligned the parts with screws and it just worked.


A few more holes and a little milling for detail and the block is nearly done.




I will add the drawings and more photos as I proceed.


Copyright 2004,  Florida Association of Model Engineers and engine builder as noted above, All rights reserved.