Gingery Atkinson Cycle Engine

[jasonh]

I completed this engine to a running state a couple of weeks ago. I need to take it apart now and get the parts powder coated so that it looks pretty. It's a by-the-plans rendition of the Atkinson engine described in Vince Gingery's book. As my first four stroke it was a nice engine to build and runs quite well.

[ame]http://youtu.be/Il5TUwxQyNc[/ame]

 

[Brian Rupnow]

That is an amazing piece of work!!! I love it. I am about 90% finished with my Atkinson build, from plans by Jan Ridder. I have never used a vapour carb before, but your engine seems to do very well with one.---Brian

 

[jasonh]

Brian - I saw Jan Ridders site the other day. It looks like he has taken the same basic layout but has added his own elements- ie bar stock build, overhead cams and a vapor carb. I contemplated a vapor carb, because I thought it would be simpler, but eventually I just plowed on with the needle valve/venturi style carb presented in the book. As it happens neither the build nor the operation of that style of carb presented any significant issues- and I'm happy that I have a known good design I can use on other engines.

Best of luck with the remaining 10% on your engine - I know it often seems that the last 10% takes about 80% of the build time.

Jason H.

 

[nemoc]

Hi Jason, That"s a beautiful engine. Runs and sounds great :bow: :bow: :bow:

Craig

 

[steamboat willie]

Jasonh,
That's one mighty fine looking engine you have there! I heartily approve!
Bill Atkinson
Canberra, Australia
(what - me biased??? - never...)

 

[Brian Rupnow]

So Jason---I'm in a quandry here. As you will be well aware, the Atkinson has two different strokes. On one stroke the piston gets closer to top dead center than on the other stroke. What I need to know is , which one is the power stroke, when the engine fires.---Brian

 

[jasonh]

Brian:

Strokes:
Yes - two different strokes- a short intake stroke and a long power stroke.
When the spark occurs at the start of the power stroke the piston is essentially just the gasket thickness away from the cylinder head.
At the start of the intake stroke the piston is still very close to the head (I had some issues with valve clearance) but does not descend as far into the cylinder bore.

Carburettor:
I'm using the design from the Gingery book. ie- A needle valve (literally - it's a #18 darning needle) in a small orifice (#70) drilled in a brass jet.
A rotating throttle body controls the airflow. Operation of the carburettor has been confirmed by seeing it sneeze in the wrong direction when my intake valve timing was too long.

The fact that your engine runs for a while and then dies is interesting. It suggests (to me anyway) that the basic mechanics are ok but that there maybe fuel or electrical issues. How's your spark? I managed to burn out a coil, and before it died completely and it gave symptoms similar to what you are describing.

Good luck,

Jason H.