My Improved Snow Engine

[Rustkolector]

This is the preverbial Snow tandem double acting gas engine designed by Doug Kelley that I built in 2008. It is my favorite model engine. I never took any video of it at the time. Over the years this little engine and I have had our ups and downs and finally last year we had a bit of an accident, I admit, it was my fault. So over the last year I rebuilt this Snow and was determined to incorporate what I think are some needed changes to address the issues I was having with my Snow engine. In particular, my Snow would not continue to run without running at a very high rate of speed making everything moving on the engine a complete blur. Other Snow owners might be familiar with these issues.

So far, it seems to be running well and it will now continue running through a tank full of fuel. The engine is running at 350 RPM in the video.
Jeff

<a href="https://www.youtube.com/watch?v=c5QfKuCBlbw" target="_blank">http://www.youtube.com/watch?v=c5QfKuCBlbw</a>

[crueby]

Very nice!

[Don1966]

Awesome runs a treat..... 



 
Don

[Art K]

Jeff,
It runs great, good job on the rebuild.
Art

[gldavison]

Fantastic.   

[fumopuc]

Hi Jeff,
a real pleasure to watch the very smooth motion.
Is the carb the one which Roy Sholl offers at his shop ?
The 3 mm type ?

[gary.a.ayres]

Wow!

Now that is a thing of beauty...

 

[Chipmaster]

Marvellous, could we have a longer video please?

Andy

[Roger B]

Excellent     

[awake]

Superb! Out of curiosity, what were some of the things you needed to do to get it to run slow & steady?

[Rustkolector]

Achim,
Yes the carb I am presently using is a 3mm size from Roy Sholl.

Andy,
The two most significant improvements were a different cam profile and a heated intake manifold. The volumetric efficiency of a single cam Snow engine is poor. It just can't scavenge well at no load with equal duration of intake and exhaust strokes. More conventional valve timing was enabled using the new cam lobe profile. Even the real ones didn't run well at no load. The intake manifold was changed to a simple single plane log type to reduce the length of the runs, and to prevent any accumulation of liquid fuel and oil. This improvement helped a bit, but it still ran very cold. Jacket water heat was added to the manifold and to the center carb mounting block. This helped a great deal provided the engine is run long enough to warm the coolant. The engine temp for the video was about 130F (very hot to the touch). It runs even better at 160F. Fuel consumption is greatly improved when warmed up.
Jeff