# Four Square Engine Plans



## vederstein (Jan 16, 2022)

This is a continuation of the "Un-Named Engine" thread.  I've since actually named this thing "Four Square".











As promised, here's the plans.

I highly suggest you read up on the Un-Named Engine thread.  This design requires significant air pressure to run because of the engine geometry.  It can be greatly improved as demonstrated near the end of the thread.  It does run, but expect to have 60-80 psi on this thing to run.

PDF Assembly drawings first.


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## vederstein (Jan 16, 2022)

Now the individual part drawings:


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## vederstein (Jan 16, 2022)

And finally the 3D cad file in Step format.


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## vederstein (Jan 16, 2022)

Now some pictures of the final design and the obligatory video of the engine running:


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## oldengineguy (Jan 16, 2022)

Interesting  engine! What year is the T.D. in the background?   Colin


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## vederstein (Jan 16, 2022)

The TD is from '52.


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## James Barker (Jan 16, 2022)

Ved', Thank you for sharing with us all here. Looks like a swell runner. 

BC1
Jim


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## vederstein (Mar 13, 2022)

I make some non-documented improvements to the engine.  The most important change being that I went to smaller valve springs and added a screw such that I can adjust the spring compression.  This allows adjustment of the spring pressure to just what's required to reliably keep the valves in contact with the cams.

I went from around 55-60 psi down to reliably idling at 25 psi:  A Big Improvement!

Video, with comments below:


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