Oddball engines and prototypes

[katinas]

Perhaps trying to maximize bottom end power for stadium Superenduro ???

Everyone who tried it are very satisfied and yes much better througth rev range than older ones.

Upd. After 16 hours of run, piston ring snagging again. Very clear boundaries of piston dome color.

[Pursang]

Here is a video with some interesting moments (and a fair bit of Seppo Youtube Wankerism)

https://www.youtube.com/watch?v=LyI3KWMWbB4

Tip: watch without sound, pick through the bits with the viewing peaks.

Overview: 3D printed carbon fibre reinforced piston fitted in an old quad bike.

Test run: repeating slow U turns and accelerating, up to 42 mph.

Results: lasted 1min 30sec. Top ring separated and stuck in top of bore.

Melted crown, but skirt and gudgeon pin looks OK. (Go to minute 26).

My Take: Idea has some potential, if development and testing is done under controlled conditions.
eg, I think, at one point, some extra height was arbitrarily added to the crown. If it was detonating it would probably be quieter than usual.
Perhaps it needs an alloy insert to protect the crown and conduct some heat through the rings.
Different combinations of carbon and poly might be more heat resistant.
Perhaps oven/kiln baking to reduce the Poly and Set the carbon could work. Lots of ideas to investigate. Please let me know, when You get it right!

[ken seeber]

Firstly, I have to agree with your introduction words Dazza.

Irrespective of the clearances, profile and squish, a few things come to mind:

The ring groove. As the seat of the groove must be very flat and smooth for ring sealing, I’m not sure how good this could have been, direct off the printer. Despite being a flat surface in the X & Y directions of the print head, there is every chance for some waviness and minor projections. This means leakage = high temps = death.

From some views it looks like some form of ring anti-rotation is present. As they didn’t mention an actual pin, then one can assume that it was a printed projection at the base of the groove. This would prevent any lathe turning to smooth up the groove.

With the much lower thermal conductivity of the printed material being far less than aluminium, the crown surface temp would inevitable been very high. As the glass transition temp of even the highest temp printer materials is around 180C, there is the likelihood of bits just falling off, just as in the vid = death.

Not sure if they reamed out the piston pin bore and what form of retention was used.

It just shows that aluminium is pretty good stuff.

It also shows than many things can be made to work, it’s just a matter for how long.

Anyways it was interesting, to a point.