The Most Reliable Engines: What Makes Them Tick?

A lot of people can tell you what makes an engine more powerful. You can look at the displacement, you can look at the compression ratio, the amount of boost it makes if it's turbocharged. You can get a pretty good idea of how much horsepower in engine should make. But what makes an engine more reliable? What are the pieces that contribute the most to reliability?

And what things do the most reliable engines have in common? We looked at a ton of engines, talk to mechanics, drove through junk yards and today we're gonna show you what we found out, what the most reliable engines have inside them.

A Big Thanks to Keeps for Sponsorship Today's Video

We wanted to find out what makes an engine go the distance. To do this, we looked at a ton of engines, talked to mechanics, and even drove through junk yards to get a better understanding of what contributes to reliability.

What We Found Out

We found that there are several key factors that contribute to an engine's reliability. These include things like materials, design, and manufacturing processes.

We also discovered that the most reliable engines have some common characteristics, such as simple designs, robust materials, and careful attention to detail in the manufacturing process.

How You Can Get an Engine to Go a Million Miles

So what can you do to make sure your engine lasts for a million miles or more? We'll be sharing our top tips and secrets for keeping your engine running smoothly and reliably for years to come.

WEBVTTKind: captionsLanguage: en- A lot of people can tell you what makesan engine more powerful.You can look at the displacement,you can look at the compression ratio,the amount of boost itmakes if it's turbocharged.You can get a pretty goodidea of how much horsepowerin engine should make.But what makes an engine more reliable?What are the pieces thatcontribute the most to reliability?And what things do the mostreliable engines have in common?We looked at a ton ofengines, talk to mechanics,drove through junk yards andtoday we're gonna show youwhat we found out, whatthe most reliable engineshave inside them, andthen we're gonna tell youhow you can get an engine togo a million miles, let's go!(energetic upbeat music)- A big thanks to Keeps forsponsoring today's video.Thank you Keeps.- Uncle Jerry, I'm heating up your soup.- Thank you, nurse Nolan.- I'm not your nurse uncle Jerry.- Mmh, he's a peach.Ah, help, nurse Nolan couldyou help me out please?Okay, calm down Dave, calm down.Ever since I took Dave out of the basementhe's been eyeing my melon likeit's one of his precious ex.I told him, "This is no egg, Dave.I just happened to be one ofthe two out of the three guysto experience some formof male pattern baldness."But he wouldn't listen,that's deep flesh wounds.Maybe if I were to use Keeps,this wouldn't have happened.Keeps makes it easy by havinghair loss consultations onlinewith real doctors, then theyship your hair loss medicationdirectly through yourdoor every three monthsso you don't have to worry aboutyour follicles failing you.So when you're ready tostart your treatment,head on over to keeps.com/b2band get 50% off your first order.That's exactly half in caseyou didn't know that number.Hey, nurse Nolan, forget the soup,I'm ready for my sponge bath.- Oh!- Or you might've heard ofsomeone blowing a motor,and that is a pretty broad term,but to put it simply ablown motor is any damagethat is severe enough to requirean engine rebuild or engine swap,when it comes to reliabilityand damage over time,the biggest culprit of these failuresis some form of overheating.Overheating it can warp metalcomponents in an engine,it can melt or wear out gasketsand it can cause high pressuresand spots not designedto stand up to those pressures.So to combat overheating andengine has two main methods,good cooling and good oiling.Coolant gets chilled inyour radiator then flowsthrough the engine, cooling the metalsand gathering heat to takeit back to the radiator,to be cooled again.The pathways for thecoolant have got a coolthe entire block, not justthe first few cylinders.And engines like the Toyota3VZ, the coolant channelsare a little too small andin slow speed applicationslike off-roading, theradiator would strugglegetting the coolant cool enoughand it would be too hot by the time it gotto the furthest cylinders.That made for a prettycommon failure pointin the 3VZ's original head gasket.But the oil also prevents overheating.Engine oil is a lubricant betweenmetal parts in the engine,and a lubricant reduces frictionbetween those two metals,which means less heat.Now engines that have highcoolant and oil capacities tendto be some of the longerlasting, more reliable engines.Think about it, if a small engine losesa quarter liter of oil, it'sgonna have a bigger effectthan it would on a bigger engine.Bigger engines got more oil,so that loss of oil has lesseffect on the total volumeof oil in that engine.But it doesn't mean that youcan't have a good small engine.Honda's F series and even Toyotais 22RE, I used to have onein my Toyota pickup truck,frigging love that thing.I drove it without oil for a long time.Hey, if you know wheremy truck is calling meI want it back, my sister stole it.And one of the other thingsthat can affect oilingis actually your fuel.Have you ever noticedthat diesel engines tendto be more reliable than petrol engines?That's because petroleum-basedfuel is a detergent,it cleans the microfilm ofoil off the cylinder wallsand then as the pistongoes back up that oilis no longer there, butdiesel fuel actually actsas a lubricant and easesthe wear on the pistons.Engines like the Mercedes OM617and the Volkswagen 1.9 TDIcan easily do over 300,000 miles.But overheating is not theonly way that temperature comesinto play with engine reliability.I'm talking about thermal expansion.Now an engine has two mainparts to it, it's got the head,it's got the block, the headis where the valve train is,and the block is where yourpiston rods and crankshaft are.In between them is the head gasket,ahead and block are two separate piecesso that the engineinternals can be assembled.If it was just one pieceyou'd never be ableto get your pistons in there.So it's gotta be two pieces and the gasketin between those two pieceshas gotta be really good to prevent leaks.So now that you know thatwe got these two pieceswhat material do you make them out of?And you can make them out of cast iron,it's strong and cheap,but it's really heavyand it doesn't dissipate heat really well.Or you can make them out of aluminum,it's lighter and it's betterfor cooling, but it costs moreand it expands more whenmore heat is put to it.It's like a thousandth of an inch,but it's enough to get the precise partsof your engine rubbing against each other.And overheating cylindercan cause the pistonsand rings expand anddamage the cylinder walls.And then when the engine cools again,you got more space thereand you lose compressionand start burning oil, that's all bad.Aluminum expands more thantwice as much as cast ironwith the same change in temperature.It's because of this thatsome very reliable engineshave an iron block, but in aluminum head,you get the heat releaseof the aluminum in the headwith the rigidity of the iron block.This is obviously thebest setup in any enginewith an iron block and an aluminum headshould be good to go, right?Wrong, some of the leastreliable engines of the worldare also iron block andaluminum head combos.It all comes back to thermal expansion,as the engine heats up tonormal operating temperaturesthe block and head expandat two different ratesbecause they're made upof two different metals.Then when you turn theengine off they cool downat different rates as well.This starts to create a grindingeffect on the head gasketand over time it gets weaker and weaker.Engines that have this issue can be fixedwith a really strong headgasket, but if you're lookingfor top tier reliabilityyou'd want an iron blockand you'd want an iron head.But while all this is goingon inside of the enginethere are some telltalesigns outside of the enginethat can show you if yourengine is reliable or not.Picture a four cylinder engine,as pistons one and four go down,pistons two and three, go up.The inertia of the pistons going upis the same as the inertiaof the pistons going down.They balance each other out,now picture a V6 engine.Here no pistons are upand down at the same time,pistons one and two,they're connected atthe same crankshaft pen,and as they come up one after the other,the other four pistons are mid strokeand that makes this engine want to shake,this is called harmonic discordance,and it comes from an imbalancein the primary forcescaused by the pistons.Inline foreign engines cancelout these primary forces,reducing vibration andtherefore reducing wear.But they're not perfect,there are secondary forcesand these are caused by thepiston movement in the cylinder.So when a piston goes up anddown it actually travels fasterin the top half of the cylinderthan it does the bottom path.So at halfway throughthe pistons movement,it has moved half the length of the strokeplus a little bit extra.The primary forces are balanced,these secondary forces they are not.An engine like a straight-sixhas both the primaryand secondary forces balanced.Because of this, some ofthe most reliable enginesare straight-sixes,the Plymouth Slant-Six,the AMC inline-six and the Merc OM606can make it to 400,000miles with good maintenance.So if we take everything we've learned,large oil capacity, inline-six,all iron constructionand diesel lubrication, andwe searched for an enginewith all those traits, what would we find?We are looking at the all ironstraight-six turbo diesel,the Cummins 6BT 12 valve,this engine is so reliable,it outlasts the trucks that it comes in.Cummins actually has a million mile club,they send you a new cap plateto stick it on your truckonce you reach that million miles.It's kind of like ourown donut undergroundwhere we'll give you freestickers every couple of monthswith a bunch of other cool bonus stuff,you get to watch some behind the scenesof B2B and all other shows.- Do you need Alexis first aid kit?- Wow, I bet thosebandaids are expired.(chuckling)- Listen, they're not, I don'tthink bandaids expire, right?That's not a thing that's expirable.Do you wanna join?Hit that join button down below.So it looks like our theories work though.We took all the parts thatmake an engine reliable,put them in one engineand came away with oneof the most reliable engines on the road,that was pretty easy, almost too easy.What if I told you thatthere was an enginethat has gone hundredsof thousands of miles,some well over a millionmiles and it has almost noneof the reliability markerswe just talked about.It's Toyota's V8 from the 90s and 2000s.The beast inside thefamous million mile Tundra,in the engine, in my GX470, the 2UZ-FE.Now for those of youwho don't know in 2016,Toyota Tundra owner Vic Shepardwas given a brand new truckfrom Toyota in exchange for his 2007 modelthat had over a millionmiles on the odometer.But the 2UZ is nothing likewhat we described as reliable.Cross playing V8 like the 2UZneed a weighted counter shaftto balance out those primary forces.It's still balanced, but itadds weight and lowers peak RPM.The 2UZ also has half the oilcapacity of the Cummins 6BT.And it's also got an ironblock with an aluminum head.So how in the heck did this enginemake it past a million miles?Is it really good maintenance,or Toyota's just super over engineered?Well, yeah, it's thosethings but it mainlyhas to do with engine cycles.We measure an engines lifespan by milesbecause that's really theonly metric that we have.And it's that part thatwe as drivers care about.But for an engine the truecounter on its lifespanis engine cycles, when youstart the car to drive to work,the engine is cold, itworks just a little harderto warm itself up but then it's cruisingalong at operating temperature.And once you get to work, youpark the car, you turn it offand then the engine cools down.Once it's cool again, that's one cycleand when you drive back homefrom work, that's another cycleand each cycles, themetals expand and contract.But they don't really carehow many miles you drivein between those cycles, whetheryour commute is two milesor 200 miles, it's still only two cycles.Now, Vic Shepard's Tundra was a 2007and it was gifted to Toyota in 2016which means our buddy Vicdrove 125,000 miles a year,that's 10 times morethan the average person,but it's still only 10 yearsworth of engine cycles.Maybe even less, because ifyou're driving all day longyour engine doesn't alwayshave time to cool down.Start up and cool down are thehardest times for an engine.If you've ever taken a warmglass out of the dishwasherand put ice water in it,there's a chance itshattered right in your hand,the rapid change in temperature contractsthe glass weakening it.And the more drastic the change,the more stress it's under,well, that's exactly what'shappening in your engine.And that's just not the block in the headthat's all the components.So even though this Tundraengine made it 1 million milesit had gone through the enginecycle of 120,000 mile car.Now the 2UZ it's stilla dependable engine,forgetting engine cycles.It's got really good cooling,it's got very strong head gasket,so they can still goa long way regardless.And there are other enginesof all kinds of configurationsand sizes that areexceptions to these rules.But on top of the enginesown parts use caseis an important part ofcalculating engine reliabilityand longevity, even if you havea quote "bulletproof engine"how you use it is going tomake all the difference.But at least now, youknow exactly what you needto choose a reliable enginefor yourself and keep it goingtill the end of time, or untilyou give it to your sisterand then she sells it out from under you.Let us note down in thecomments what we should swapinto Pumphrey's AE86,they pulled his engine outand money pit if you haven'tseen it, check out that episodefollow Donut Media on Instagramand Twitter @donutmedia.Follow me on Instagram @jeremiahburton.And until next time, bye for now.(soft upbeat music)