Jeff Henise Casting Motorcycle Racing Cylinders

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GreenTwin

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There is a guy out west named Jeff Henise who casts racing motorcycle cylinders in aluminum, and races his motorcycle using his cylinders.

Making a good looking casting is one thing.
Machining that part and using it under racing condtions takes it to a whole new level, and definitely proves that not only do your castings look impressive, but they actually function under very rigorous conditions.

Here is Jeff's channel:

https://www.youtube.com/user/jhenise/videos


And here are photos of Jeff's cylinder work.
And it shows that you don't need lost foam to make a rather complex engine parts.

Jeff's patterns are reusable, and so they can be used over and over again.


This method makes far more sense to me than a one-off lost foam method, but to each their own I guess.

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Jeff is just a genius-grade guy.
He researched sand and binder types, pattern coatings, release agents, and created sand hardness tests, to measure which product worked best.
He posted his tests for many types of foundry sand, some of which used binders.
It is the most comprehensive approach to figuring out the best mold material to use that I have ever seen.

He tried green sand (water-based), Petrobond (oil-based), resin bound sand, and sodium silicate bound sand.
For his bound molds, he used Oaklahoma 85, which is a white ~85 AFS silica sand (often called OK85).
OK85 is also the sand I use with a resin binder, and I consider it to be the best commercial-grade foundry sand available.

The photos of how he made the cores for the passages for his 2-stroke racing engines are fascinating.
Resin-bound sand can be used for both the mold and the cores, and multi-part cores can be assembled and cemented together, which is the method Jeff used. He uses a zircon refractory wash on his cores to get a very smooth passage finish.
I use a ceramic alcohol-based mold wash, which I spray onto the core(s) and the interior of the mold, and it gives a superb finish, and stops the metal from penetrating the sand.

As as I mentioned, Jeff appears to be self-taught.
He looked at all the options available, tested multiple products and methods, and then picked the best materials for his purpose.
His casting results speak for themselves, and his cylinders functioned very well under high-rpm racing conditions, according to Jeff.

One trick I learned with resin-bound sand is to use a small auto body slide hammer, with a forked end.
I put one or two screws in the pattern, and then lightly tap with the slide hammer, keeping a hand on top of the pattern, not moving the pattern, but breaking the bond between the pattern and the resin sand.

For a small pattern, it can be one screw in the center.
For large patterns, you may need two or more screws, and you basically use the slide hammer all around.
Once the bond has been broken, you can lift out the pattern easily by hand.

You really don't want a slow pull like Jeff does with his extractor, at least not initially, since you can tear the sand by pulling slow.
The light blow of the slide hammer breaks the bond without damaging the resin-bound mold.

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