Another Elmer's OCR

[SignalFailure]

The aquarium pump will run my twin oscillator and 'Double Scotch' but as I mentioned above it wouldn't run 'Scotty' or the Elmer's Opposed I built (can't run that on anything!) so maybe a single-cylinder single-acting rotary-valve is too much to ask. I'm going to try all the tweaks and maybe remake some bits and see it it'll go nevertheless.

Thanks again for the pointers, appreciate it!

EDIT: Thanks Marv... I was eyeing up a £25 ($25?) compressor the other day but maybe the £100 'proper' version would be sensible...

MB: Rest assured i've tried it every which way My twin oscillator would only run when up-ended until it was well broken in!

 

[SignalFailure]

Opened up the inlet 'tube' from 1.5mm to about 1.7mm. Opened up the horizintal passageways about the same and the vertical passage to about 1.8mm (I think the vertical passage isn't quite centred precisely over the top of the shaft). Lapped the face of the valve. Re-fitted the original shaft which I think was better. Re-soldered the flange to the copper tube as not certain it was 100% airtight. Fitted a brass spacer between crank disc and bearing.

Managed to get it running for a few strokes on the aquarium pump while held upside down! More tweaking should do it. Thanks for all the tips!

[youtube=425,344]2OlTK-oKS7c[/youtube]

 

[mklotz]

On the OCR and other of Elmer's engines that use the OCR valve style, you can improve performance by replacing the spring that friction holds the valve disk in place with a small thumbnut. This requires loosening said nut to change direction but the pressure of the nut holds the valve down tight when running and prevents leaks.

 

[rake60]

When I built Elmer's OCR I didn't have a spring that fit the pressure
requirements. I cut a very short section of aquarium air line to fit under
reversing valve in place of a spring. It works just fine!

Rick