If an engine has four cylinders, chances are they’re arranged in-line—unless that engine was made by Subaru, of course. A boxer-four is second only to all-wheel drive as a Subaru calling card. But the mad Russians at Garage 54 laugh in the face of the status quo, so they decided to convert a Subaru boxer-four into an inline-four.
These are the same YouTubers that tried to make a diesel engine run on gasoline, and built a V16 out of chainsaw engines, but this project was even more technically challenging. It started by cutting a boxer engine in half and placing the two cylinder banks side by side vertically. The water pump is attached to one bank of cylinders from the factory, so that bank became the front of the new inline-four. This reorientation also meant a timing belt from a Toyota 1JZ fit perfectly.
Putting two formerly opposed cylinder banks next to each other made the engine twice as long as the original boxer four, so a second engine was sourced to provide a crankcase, which was welded to the one from the first engine. Similarly, the cylinder heads are made from a pair of stock heads welded together.
The same procedure was followed with the rotating parts. The camshafts are made from two factory cams welded end to end, and oriented so they maintain the stock timing. The crankshaft is made from two factory cranks, coupled together with custom-fabricated tabs. That sounds straightforward enough, but assembly was a bit tricky because, unlike with a conventional inline-four, there was nothing to secure the crankshaft as the top and bottom ends were put together.
We convert a Subaru boxer engine into an inline-4
The cut-and-stitch design also means that, instead of one oil pan on the bottom of the engine, the inline-four has two oil pans on either side. Getting that situation to work is a job for a future video, along with the intake and exhaust manifolds, plumbing, and pulleys. But the engine is fully assembled and turns, which is quite an achievement on its own.
Subaru fans might ask why you would cut up one of these unusual boxer engines to make the type of engine that powers nearly every car in a typical office parking lot. The answer lies in not thinking about it too much.