Fridge Compressor Turned Into Capable Little Four-Stroke Engine

Never underestimate the power of a well-stocked junk bin. Along with a TIG welder and mechanical ingenuity bordering on genius-level, all of which come to bear on this fridge compressor to four-stroke engine build.

The video posted by [Let’s Learn Something] is long, but watching it at double speed doesn’t take away much from the enjoyment. By using a piston-type compressor, a lot of the precision machining is already taken care of here. Adding the intake and exhaust valves, camshaft, timing chain, carburetor, and ignition system are still pretty challenging tasks, though. We loved the home-made timing chain sprockets, made with nothing more than a drill and an angle grinder. In a truly inspired moment, flat-head screws are turned into valves, rocker arms are fabricated from bits of scrap, and a bolt becomes a camshaft with built-up TIG filler. Ignition and carburetion are cobbled together from more bits of scrap, resulting in an engine that fired up the first time — and promptly melted the epoxy holding the exhaust header to the cylinder head.

Now, compressor-to-engine conversions aren’t exactly new territory. We’ve seen both fridge compressors and automotive AC compressors turned into engines before. But most of what we’ve seen has been simple two-stroke engines. We’re really impressed with the skill needed to bring off a four-stroke engine like this, and we feel like we picked up quite a few junk-box tips from this one.

Thanks to [Eric Mockler] for this tip.

18 thoughts on “Fridge Compressor Turned Into Capable Little Four-Stroke Engine

  1. big clive did a recent teardown of the clone cdi used in that video. I’d like to see someone build a cdi from scratch because the implementation is terrible and the oem versions are spendy.

    1. the moment he grinder part of block surface I was like oh yeah, one of those 5 minute craft videos, next take we will see another perfectly resurfaced block. But NO, he uses the same scratched at the beginning one and it still works. The biggest surprise were screw valves, I was expecting them to bind on the thread at some point.

  2. No guard on angle grinder when cutting it open. Stopped watching after initial few seconds.
    We should not promote people who display such disregard for even most basic safety practices.

    1. They don’t call them “death wheels” for nothing.

      At least he mostly stayed out of the plane of rotation.

      You need only to have a grinding wheel or disk explode ONE TIME to make you a True Believer in safety.

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