An Unnecessary & Quite Late Lecture - 2 Stroke Vs. 4 Stroke
My thoughts on a discussion that has now long been resolved. In any case, I proceed.
The two-stroke engine is different from the four-stroke in several ways. The first and possibly the most easily-recognisable difference is apparent to every Indian and in fact everyone further east who have heard unmuffled Tuk-tuks (what we call autos) rushing up and down their streets - they sound like insects.
The reason the two stroke engine sounds distinctly different from its more advanced counterpart, is that it's doing all the work of a four-stroke engine, using only half the movement of the crankshaft. It’s the reason there are several more explosions within the cylinders in any amount of measured time, when using a two stroke engine. It translates, sounding quite harried and unsophisticated.
The only times I’ve heard fond descriptions of two-stroke engines are when friends are referring to either the Yamaha RX100 (which we can all agree is a bit of a classic at this point) or an old Jawa. Other than that, consensus seems to be against the resilient little thing.
My opinion is that the two-stroke engine doesn’t necessarily need to exist outside of it’s duties as an engine for lawnmowers and leaf-blowers. They’re considerably less easy to maintain for multiple reasons. You require a special mix of fuel and oil for two-stroke engines because lubricating oil is not supplied from within the engine (while four-stroke engines supply lubricant from within the crank-case).
We all know the smell of two-stroke exhaust but can’t really put our finger on the four stroke’s bouquet. The smoke emitted by a two-stroke engine contains plenty of the oil mixed with the fuel as it isn’t fully burnt within the cylinders, rendering it the distinct smell we all remember. The environmentally minded unsurprisingly despise the two-stroke. As you may have realised by now, there is a recurring trend with this engine - it’s lack of sophistication.
However, advantages to the two-stroke should be mentioned. As its piston movement is essentially halved when compared to the four-stroke, full revolutions can be more quickly completed and the engine can therefore be revved significantly higher. This improves acceleration drastically, which is why whenever you do see an old RX on the road, it’s going faster than you (and making its presence felt).
With regard to the four-stroke engine, the very staple of our motoring diet, plenty can be said. It manages the process of intake, compression, ignition, combustion and exhaust with significantly more panache than the two-stroke.
It’s come to take on several forms which have formed entire classes of car. The American V8 for example, is a four-stroke engine that defined the sound of an era. Every time we see a Mach 1 or a classic Fastback, we think V8. The V12 on the other hand formed the sound of an era within Formula 1, which has now passed. We will never forget the high pitched whine that accompanied speeds of above 200 miles an hour on the straight at Circuit de la Sarthe. Even the modern autos manufactured by Bajaj use moderately powered four-strokes to carry their passengers with some level of inconspicuousness. This engine has from the beginning, been the block upon which the greatest manufacturers have built.