Remarkable two stroke Winfield Model T engine on eBay

Here’s a link to the advertisement:

This undoubtedly would be crazy powerful if perhaps only briefly. It would be fascinating to know just what race it was built for. An engine of this nature would put out insane horsepower for a brief period of time before destroying itself. You can see evidence of pre - ignition or possibly detonation on the inboard cylinders. The remarkable nature of Ed Winfield’s brain is on full display here. This is likely not something that I would want to risk running for fear the irreplaceable parts might be lost forever.

From what I can tell the supercharged air / fuel mixture comes into the inner cylinders as the pistons clear the port in the side of the cylinder wall. The inner cylinders are a smaller diameter as they are receiving the high velocity / high pressure incoming mix. As the pistons go past bottom dead center fuel / air is still coming in. Meanwhile the outer cylinders are exhausting spent gases from the previous cycle. They are larger diameter so they can be more efficient for that task. The inner cylinders close off the intake port and intake charge goes through the cylinder head to fill the outer chambers with ignitable mixture.

Just before top dead center the spark plug lights the mixture in the pair of joined cylinders. The engine operates as if it were a big twin. There is one firing impulse every time a pair of cylinders reaches the top of the stroke, so one firing impulse every 180 degrees of crankshaft rotation.

There is no camshaft or valves. A spur gear runs the timer mounted in its normal spot on the timing cover The timer is wired so that it fires each cylinder every time it reaches TDC, so as you can see there are pairs of terminals 180 degrees apart wired together. Two coils are used because you effectively only have two cylinders.

The inner cylinders are sized in a ratio to make them more or less equal to the outers when power is applied. I bet it was an interesting balance job!