What's inside a Million Mile Engine?

- Many people can tell you

what

makes an

engine

more powerful. You can look at the displacement, you can look at the compression ratio, how much boost it makes if it's turbocharged. You can have a pretty good idea of ​​how much horsepower the

engine

should make. But

what

makes an engine more reliable? What are the parts that contribute the most to reliability? And what do the most reliable engines have in common? We looked at a lot of engines, talked to mechanics, drove through junkyards and today we're going to show you what we discovered, what the most reliable engines have inside and then we'll tell you how you can get them. an engine to travel a

million

mile

s, come on! (energetic, upbeat music) - Big thanks to Keeps for sponsoring today's video.

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Keeps makes it easy by having online hair loss consultations with real doctors, then they ship your hair loss medications directly to his door every three months so he doesn't have to worry about his follicles failing him. So when you're ready to start your treatment, visit Keeps.com/b2b and get 50% off your first order. That's exactly half in case you didn't know that number. Hey, Nurse Nolan, forget about the soup, I'm ready for my sponge bath. - Oh! - Or you may have heard of someone having a blown engine, and that's a pretty broad term, but to put it simply, a blown engine is any damage that is serious enough to require an engine rebuild or swap, when It's about reliability. and damage over time, the biggest culprit for these failures is some type of overheating.

Overheating can warp metal components in an engine, can melt or wear gaskets, and can cause high pressures and points that are not designed to withstand those pressures. Therefore, to combat engine overheating there are two main methods, good cooling and good lubrication. The coolant cools in the radiator and then flows through the engine, cooling the metals and building up heat to be carried back to the radiator and cooled again. The coolant pathways cool the entire block, not just the first few cylinders. And in engines like the Toyota 3VZ, the coolant channels are too small, and in low-speed applications like off-roading, the radiator would struggle to cool the coolant enough and would be too hot by the time it reached the farthest cylinders.

That created a fairly common failure point in the original 3VZ head gasket. But the oil also prevents overheating. Motor oil is a lubricant between the metal parts of the engine and a lubricant reduces the friction between those two metals, which means less heat. Now, engines that have high coolant and oil capacities tend to be some of the most reliable and long-lasting engines. Think about it, if a small engine leaks a quarter of a liter of oil, it will have a greater effect than it would on a larger engine. Larger engines got more oil, so oil loss has less effect on the total volume of oil in that engine.

But that doesn't mean you can't have a good small engine. The F series from Honda and even Toyota is 22RE, I used to have one in my Toyota truck, I love that thing. I drove it without oil for a long time. Hey, if you know where my truck calls me, I want it back, my sister stole it. And one of the other things that can affect lubrication is actually fuel. Have you ever noticed that diesel engines tend to be more reliable than gasoline engines? This is because petroleum based fuel is a detergent, it cleans the micro film of oil off the cylinder walls and then when the piston comes back up the oil is no longer there but the diesel fuel actually acts as lubricant and relieves wear on pistons. .

Engines like the Mercedes OM617 and Volkswagen 1.9 TDI can easily go over 300,000

mile

s. But overheating isn't the only way temperature influences engine reliability. I'm talking about thermal expansion. Now, an engine has two main parts: it has the head, it has the block, the head is where the valve train is and the block is where the piston rods and crankshaft are. Among them is the head gasket, front and the block are two separate pieces so that the internal components of the engine can be assembled. If it was just one piece, you would never be able to get the pistons in there.

So it has to be two pieces and the joint between those two pieces has to be really good to prevent leaks. Now that you know we have these two pieces, what material do you make them out of? And you can make them from cast iron, it's strong and cheap, but it's very heavy and doesn't dissipate heat very well. Or you can make them out of aluminum, it's lighter and better for cooling, but costs more and expands more when more heat is applied. It's like a thousandth of an inch, but it's enough for the precise engine parts to rub against each other.

And overheating of the cylinder can cause the pistons and rings to expand and damage the cylinder walls. And then when the engine cools down again, you have more space in there, you lose compression and you start burning oil, all of that is bad. Aluminum expands more than twice as much as cast iron with the same temperature change. This is why some very reliable engines have an iron block, but in an aluminum cylinder head, you get the heat release of the aluminum in the cylinder head with the rigidity of the iron block. Obviously this is the best setup on any engine with an iron block and aluminum cylinder head, it should be ready to go, right?

Incorrect, some of the world's least reliable engines are also iron block and aluminum head combinations. It all comes back to thermal expansion, as the engine warms up to normal operating temperatures the block and cylinder head expand at two different rates because they are made of two different metals. Then when you turn off the engine, they also cool at different rates. This begins to create a grinding effect on the head gasket and over time it becomes increasingly weaker. Engines that have this problem can be fixed with a really strong head gasket, but if you're looking for top-notch reliability, you'll want an iron block and an iron head.

But while all of this is happening inside the engine, there are some telltale signs outside the engine that can show you whether your engine is reliable or not. Imagine a four-cylinder engine, while pistons one and four go down, pistons two and three go up. The inertia of the pistons going up is the same as the inertia of the pistons going down. They balance each other, now imagine a V6 engine. Here there are no pistons up and down at the same time, pistons one and two are connected in the same crankshaft pen, and as they go up one after the other, the other four pistons are in the middle of the stroke and that makes this engine want when shaking, this is called harmonic discordance and comes from an imbalance in the primary forces caused by the pistons.

Extraneous in-line motors nullify these primary forces, reducing vibration and therefore reducing wear. But they are not perfect, there are secondary forces and these are caused by the movement of the piston in the cylinder. So when a piston goes up and down, it actually travels faster in the top half of the cylinder than in the bottom half. So, halfway through the piston movement, it has moved half the stroke plus a little more. The primary forces are balanced, the secondary forces are not. An engine like an inline six has balanced primary and secondary forces. Because of this, some of the most reliable engines are the straight-six, the Plymouth Slant-Six, the AMC straight-six, and the Merc OM606 can go 400,000 miles with good maintenance.

So if we took everything we've learned - big oil capacity, inline six, all-iron construction and diesel lubrication - and looked for an engine with all those features, what would we find? We're looking at the Cummins 6BT 12-valve straight-six turbodiesel, this engine is so reliable it outlasts the trucks it comes in. Cummins actually has the

million

mile club, they send you a new cap plate to stick on your truck once you hit that million miles. It's like our own underground donut where we'll give you free stickers every two months with a bunch of other cool bonus stuff, you'll get to see some behind the scenes of B2B and all the other programs. - Do you need Alexis's first aid kit? - Wow, I bet those plasters are expired. (laughing) - Listen, they're not, I don't think band-aids expire, right?

That's not something that expires. Do you want to join? Press the join button below. However, it seems that our theories work. We took all the parts that make an engine reliable, put them into one engine and got one of the most reliable engines on the market, that was pretty easy, almost too easy. What if I told you there was an engine that had put hundreds of thousands of miles on it, some over a million miles, that had almost none of the reliability markers we just talked about? It is the Toyota V8 of the 90s and 2000s.

The beast within the famous million mile Tundra, in the engine, in my GX470, the 2UZ-FE. Now, for those of you who don't know, in 2016, Toyota Tundra owner Vic Shepard received a new Toyota truck in exchange for his 2007 model that had over a million miles on the odometer. But the 2UZ is nothing like what we describe as reliable. Cross-play V8s like the 2UZ need a weighted countershaft to balance those primary forces. It is still balanced, but adds weight and reduces maximum RPM. The 2UZ also has half the oil capacity of the Cummins 6BT. And it also has an iron block with an aluminum head.

So how the heck did this engine manage to surpass one million miles? Is this really good maintenance or is Toyota just oversized? Well, yes, it is those things, but it mainly has to do with engine cycles. We measure engine life by miles because that's really the only metric we have. And it's that part that matters to us, as drivers. But for an engine, the true counter to its useful life is the engine cycles, when you start the car to drive it to work, the engine is cold, it works a little harder to warm up, but then advances to operating temperature.

And once you get to work, you park the car, turn it off, and then the engine cools down. Once it cools down again, that's one cycle and when you drive home from work, that's another cycle and in each cycle, the metals expand and contract. But they don't really care how many miles you drive between those cycles, whether your trip is two miles or 200 miles, it's still just two cycles. Now, Vic Shepard's Tundra was a 2007 and was given to Toyota in 2016, which means our friend Vic drove 125,000 miles a year, that's 10 times more than the average person, but that's still only 10 years of engine cycles.

Maybe even less, because if you drive all day your engine doesn't always have time to cool down. Starting and cooling down are the most difficult times for an engine. If you've ever taken a hot glass out of the dishwasher and poured ice water into it, there's a chance it might break in your hand—the rapid change in temperature shrinks the glass and weakens it. And the more drastic the change, the more stress you are under, well that is exactly what is happening to your engine. And that's not just the block in the head, but all the components.

So even though this Tundra engine had 1 million miles on it, it had gone through the 120,000 mile car engine cycle. Now the 2UZ remains a reliable engine, forgetting about engine cycles. It has very good cooling, it has a very strong head gasket, so they can still go a long way anyway. And there are other engines of all types of configurations and sizes that are exceptions to these rules. But aside from the use case of the engine's own parts, it's an important part of calculating engine reliability and longevity - even if you have a "bulletproof engine" quote, how you use it will make a difference. .

But at least now you know exactly what you need to choose a reliable engine and keep it running until the end of time, or until you give it to your sister and then she sells it to you. Let's write down in the comments what we should change for Pumphrey's AE86, they took out the engine and took the money. If you haven't seen it, check out that episode and follow Donut Media on Instagram and Twitter @donutmedia. follow meon Instagram @jeremiahburton. And until next time, goodbye for now. (soft and happy music)