Results Of 3D-Printed Cylinder Head Testing Fail To Surprise

It’s the suburbanista’s weekend nightmare: you’re almost done with the weekly chores, taking the last few passes with the lawn mower, when you hear a pop and bang. The cylinder head on your mower just blew, and you’re out of commission. Or are you? You’ve got a 3D printer – couldn’t it save the day?

If this bench test of plastic cylinder heads is any indication, it’s possible – just as long as you’ve only got 40 seconds of mowing left to do. [Project Farm] has been running all sorts of tests on different materials as field-expedient cylinder heads for small gasoline engines, using everything from JB Weld epoxy to a slab of walnut. For this test, two chunky heads were printed, one from ABS, of the thermochromic variety apparently, the other in PLA. The test went pretty much as expected for something made of thermoplastic exposed to burning gasoline at high pressure, although ABS was the clear winner with two 40-second runs. The PLA only lasted half as long before the spark plug threads melted and the plug blew out. A gasket printed from flexible filament was also tested, with predictably awful results.

As bad as all this was, it still shows that 3D-printed parts are surprisingly tough. Each part was able to perform decently under a compression test, showing that they can stand up to pressure as long as there’s no heat. If nothing else, it was a learning experience. And as an aside, the cylinder heads were printed by [Terry] from the RedNeckCanadians YouTube channel. That video is worth a watch, if just for a few tips on making a 3D-printed copy of an object. Continue reading “Results Of 3D-Printed Cylinder Head Testing Fail To Surprise”

Milling A Motorcycle Engine

Real motorcycle enthusiasts design and mill their own engines. Well, perhaps that’s an overstatement. Certainly it takes to more obsession than enthusiasm to go to these lengths. But this gentleman’s modifications started out simple enough, and managed to make it to the most extreme of hardware fabrications.

The used bike came with a modified camshaft that seemed like a botched job. As he got further into tuning up engine performance the prospect of just replacing the entire thing with his own design started to grow. Using a manually¬†operated¬†milling machine he cut his own molds for the new cylinder head out of wood and sent them off to be forged out of aluminum. They come back in rough shape but he just “filed the cast without mercy” and machined the tolerances to his specifications. Apparently the first test ride had him a bit nervous — he also milled his own brakes for the bike. But after a few times around the block he gained confidence with his work.

[Thanks Carlos]