Some chassis have high milage...

I was out with some friends at a local spot not too long ago. We got to talking and some interesting things came up. One comment that stuck with me was a particular analogy one guy made comparing his wife to a car.

Immediately I thought back to this.

But anyway, on the topic of cars, the other day I was thinking about engines, pistons, and cylinders. We’ll talk about them in a second but before then, I have to complain a bit more about cars. These days, a lot of newer cars have a much higher mileage than they did years ago. For example, back when I was a kid, you’d expect a 1999 model to have very low mileage and maybe one previous owner tops. These days, that isn’t the case. These days, it’s not even a surprise to see a 2006 model that’s all greased up and rusted out.

So, getting back to those engines, pistons, and cylinders. Let’s do a little engine math for fun. (It probably won’t be that much fun). Let’s say we have a piston that has a 5.1-to-5.5-inch stroke. Let’s also say that each piston runs at an average of 1.1 strokes per second. Let’s also say that the average number of strokes during a typical run is 356 with a lower and upper limit of 259 and 454 respectively. Running with those numbers and classifying a full stroke as the piston traveling from the top of the cylinder to the bottom of the cylinder and back to the top again, we can do some math.

We can calculate the total linear stroke displacement of the piston during an engine run session. Doing just that, we get an average of 314.5 feet of linear displacement with a low end of 220.2 and a high end of 416.2. This is kind of interesting because it means that the average engine would experience 314.5 feet of relative piston motion within its cylinder during a standard run time. Running with that figure, it would only take 16.8 engine runs for the cylinder to put on one whole mile of linear displacement.

With numbers like that, it’s easy to see that an active engine would quickly put on a very large amount of mileage. This is kind of unfortunate because that means there’s going to be a lot of wear and subsequently, the cylinder is going to get a bit sloppy. Back in the good old days, only the owner would ever run an engine. They’d typically get it with low or preferably no mileage. Unfortunately, most models on the market today are heavily used. A lot of models get thoroughly test-driven before settling on their final owner.

On that note, from what I can tell, the average engine gets run 5.5 times per month. It also looks like 41.4% of engines in the 2000 to the 2004 model year range have been run at least once by one owner. If we make a conservative estimate that it takes an engine an average of 10 years to reach its final owner, we can do some more interesting math. Before we do, just to put that in context, this would be like taking a 1999 model that has its first run in 2017 but doesn’t find its forever home until 2027. That seems like a pretty long delay, but the statistics support it. The average age of an engine finding its forever home today is around 28.1 years.

Running with those numbers, the engine probably ran 5.5 times per month for 120 months. Some months it could be more and other months it could be less. It doesn’t matter too much because this is an average and purely a theoretical estimate. I’m sure there are plenty of models that have far higher mileage than this. Heck, I even recall hearing about one model that had over 300 runs in just one year. Talk about used and abused. At any rate, if we do all the math, we end up with a mileage of about 39.31 on average with a lower and upper range of 27.52 and 52.02 miles respectively. That’s a lot of miles of piston to have reciprocating through your cylinder before the engine even gets to its final owner.

A lot of people will say that this kind of mileage has no impact on the engines or their performance, but I think that’s just dumb. You can’t pump miles of piston through a cylinder without causing some damage and wear. Even if you use a ton of lube and the piston is gliding in there, it’s still going to have some sort of impact. Realistically, I’m more concerned about the rest of the engine than just the state of the cylinder. That much rough usage is going to degrade the other parts too. The last thing you want to do is drop a fortune to pick up an engine only for it to crap out on you the second the warranty is up. Heck, most of these engines these days don’t even come with a warranty.

So, I don’t know what to tell you. I guess try to avoid the high mileage models. Get a new, never-before-run model if you can afford it. Also probably get the extended warranty and get it in writing. Aside from that, if you’re going to be a moron and test drive a bunch of engines you have no intention of purchasing, first of all, screw you. You’re ruining the engine supply for everyone else. Second of all, for the love of everything sacred and holy, make sure you wrap your damn piston with some sort of protective coating. It doesn’t do much to keep the wear down, but it usually prevents a catastrophic engine failure which you don’t want to have to deal with. It will also usually keep your piston from catching rod rot which I hear is pretty bad.

Getting back to those cars though, I hear that a lot of guys are interested in EVs these days. I even heard that they’re coming out with fully autonomous robot cars. So that should be interesting if they don’t completely and utterly destroy society. That said, it kinda seems like the ICE cars are destroying society too so what can you do?

At any rate, I can’t remember where I was going with all of this, so that’s probably enough for now. We’ll see how worked up people get about the engines. It’s a shame that some people just don’t understand how they work.