Inside neglected Prius engine after 500,000 km

[enzoalec92]

https://jalopnik.com/check-out-what-a-toyota-prius-engine-looks-like-after-3-1848018980

<Check Out What A Toyota Prius Engine Looks Like After 303,000 Miles
This Prius engine was neglected, but it was still alive and kicking.

Screenshot: Speedkar99 / YouTube (Other)

A Toyota Prius has joined my shared fleet in what so far is a positive Carvana experience. Since I love knowing all I can about every vehicle in the fleet I’ve been binging all sorts of Prius videos. One of the ones that I’ve come across is a detailed teardown of a high-mileage 2004 Prius engine that looks good, even after some neglect.

A few readers have expressed concerns about picking up a Prius with 90,000 miles and expecting to run it 30,000 miles a year. That kind of driving can be hard on a car. Yet, I’ve seen plenty of second and third-generation Prii driving around in taxi service with more than 300,000 miles and still kicking. If, like me, you wonder what the engine of a high-mileage Prius looks like, YouTuber Speedkar99 tore one down and examined its wear.

The engine here is a 1.5-liter 1NZ-FXE inline-four from a second-generation Prius with 303,561 miles.

This engine uses a low compression ratio and a high expansion ratio. This works by holding the intake valve open longer for a reverse flow of intake air into the intake manifold, simulating an Atkinson-cycle engine. The result is less power but more efficiency, perfect for a hybrid. The 2ZR-FXE uses a similar system.

Screenshot: Speedkar99 / YouTube (Other)

The YouTuber informs us at the beginning of the video that the engine was running fine without issues before the teardown. The Prius the engine was taken out of was a parts vehicle.

Our host tears through the engine, giving us a thorough explanation of how everything works. But we’re here to see how this engine has fared over 17 years, and the video certainly delivers.

First up is a tour through the positive crankcase ventilation system and even the throttle body, which presents some dirty build-up and could use some good cleaning.

Screenshot: Speedkar99 / YouTube (Other)

But the valves appear to be clean thanks to the injectors.

Next, we take a peek under the timing chain cover, where things look a little discolored. The YouTuber says that this is likely because the car may have not gotten timely oil changes but even then, there isn’t a lot of wear.

Screenshot: Speedkar99 / YouTube (Other)

The camshafts and the head also look clean for the mileage they’ve gone through.

Screenshot: Speedkar99 / YouTube (Other)

Further in the teardown, the YouTuber cracked open the oil pan to reveal a sad sight.

Screenshot: Speedkar99 / YouTube (Other)

Yep, that’s sludge. They blame the sludge on cheap oil, the cheap oil filter and deferred oil changes.

The filter in the oil pump pickup tube appeared to be pretty gunked up and the pistons have some carbon buildup on them. The bigger point of concern for the YouTuber was clogged-up oil control rings on the pistons.

Screenshot: Speedkar99 / YouTube (Other)

The host explains that this could mean that the engine might not have been getting proper lubrication there.

Overall, the engine looks pretty good despite some neglect. It’s no wonder why Prii are able to rack up so many miles on their odometers when they appear to be so durable. Still, the sludge build-up is a perfect example of why you should always keep up on your maintenance.>

Quote

With Toyota's renowned reputation for building figuratively - maybe even literally! (1)(2)(3) - bulletproof vehicles throughout their history, I'm sure this Prius still running smoothly despite over a decade's worth of neglect comes as a surprise to no one. After all, Nolan Sykes explains their manufacturing process and why they're so damn reliable in this video: 

 

That being said, I still can't help but cringe at the amount of sludge buildup in the oil pan and on the timing chain and pistons. 😱 For those of you who always like to delay your car's maintenance thinking there's no point spending money when there's nothing wrong, mai tu liao!

 

[D3badge]

Have you wonder why the same engine CC size Japanese cars in generally churn out much less horsepowers? My guess is for engine reliability. Eg. F1 engine small CC but can produce 1000 hp but after a few races engine is gone.

just thinking 🤔 

[Watwheels]

13 hours ago, D3badge said:

Have you wonder why the same engine CC size Japanese cars in generally churn out much less horsepowers? My guess is for engine reliability. Eg. F1 engine small CC but can produce 1000 hp but after a few races engine is gone.

just thinking 🤔 

FYI the Prius engine's combustion cycle is running on Atkinson cycle, there is also a 2.5L engine also running on Atkinson cycle in their hybrid vehicles. Most other Toyota engines are running on Otto cycle.

Go Google what is Atkinson cycle in a combustion engine and what is Otto cycle.

You cannot compare passenger cars with F1 cars. They have to meet different sets of rules. Passenger cars have to meet FC and CO2 emissions. F1 cars have to meet their F1 regulations. Not an Apple to Apple comparison.

 

Edited November 10, 2021 by Watwheels

[Watwheels]

Notice the cylinders and pistons isnt in cylindrical shape. It doesnt look exactly round. It somewhat looks squarish almost.

That's because Toyota is trying to use bigger valves for both intake and exhaust.

[Sdf4786k]

14 hours ago, D3badge said:

Have you wonder why the same engine CC size Japanese cars in generally churn out much less horsepowers? My guess is for engine reliability. Eg. F1 engine small CC but can produce 1000 hp but after a few races engine is gone.

just thinking 🤔 

The same goes for small Cc engine n go mod to try to make a donkey run like a horse but end up looking like an ass when the car becomes unreliable.. of course there are the 2JZ engines that comes stock n can mod to 1000bhp but in this current era, there are few that reach that level .. like James Bond would say .. live to die another day or no time to die 😂 

[Unfazed]

Wow 😮

Thanks to TS for this vid! Would be interesting to see same kinda vids for other engines too.

Now that engine would need a thorough cleanup it seems, look at the sludge buildup too.

[Unfazed]

@Watwheels 

2 hours ago, Watwheels said:

FYI the Prius engine's combustion cycle is running on Atkinson cycle, there is also a 2.5L engine also running on Atkinson cycle in their hybrid vehicles. Most other Toyota engines are running on Otto cycle.

Go Google what is Atkinson cycle in a combustion engine and what is Otto cycle.

You cannot compare passenger cars with F1 cars. They have to meet different sets of rules. Passenger cars have to meet FC and CO2 emissions. F1 cars have to meet their F1 regulations. Not an Apple to Apple comparison.

 

Thank you for this great vid too to let us know the different kind of engine Toyota is using, now i wonder does the NR series of Toyota engines in models like Vios uses the Otto cycle?

Wah....with this vid and the vid from TS, where is our Anti-T or Toyota basher when we need some healthy debates? 😆😉

[enzoalec92]

On 11/9/2021 at 7:53 PM, D3badge said:

Have you wonder why the same engine CC size Japanese cars in generally churn out much less horsepowers? My guess is for engine reliability. Eg. F1 engine small CC but can produce 1000 hp but after a few races engine is gone.

just thinking 🤔 

 

On 11/10/2021 at 8:50 AM, Watwheels said:

FYI the Prius engine's combustion cycle is running on Atkinson cycle, there is also a 2.5L engine also running on Atkinson cycle in their hybrid vehicles. Most other Toyota engines are running on Otto cycle.

Go Google what is Atkinson cycle in a combustion engine and what is Otto cycle.

You cannot compare passenger cars with F1 cars. They have to meet different sets of rules. Passenger cars have to meet FC and CO2 emissions. F1 cars have to meet their F1 regulations. Not an Apple to Apple comparison.

 

Thanks @Watwheels for highlighting from the article the Atkinson-cycle aspect of this engine and linking a video for those who may not know what it means! It's amazing how much the humble internal combustion engine has evolved in the car's nearly 1.5-century history!

Thanks also for answering @D3badge's question already! I'd just like to add that not only do the design considerations differ between consumer and racing cars, but they also run on different fuels. Road cars are tuned for long-term reliability and maximum fuel efficiency at far lower speeds, so they have lower compression ratios and usually consume just 95 RON petrol that's a worldwide standard. Meanwhile, F1 engines are designed to extract the maximum amount of horsepower without (much) consideration for durability - mostly as long as they last a few races - so they run special blends specifically tailored to each team's engine. Next year, they'll even have to switch to E10, which will certainly shake things up even more than just the new aero packages.

On 11/10/2021 at 9:01 AM, Watwheels said:

Notice the cylinders and pistons isnt in cylindrical shape. It doesnt look exactly round. It somewhat looks squarish almost.

That's because Toyota is trying to use bigger valves for both intake and exhaust.

That's an interesting observation, and it definitely makes sense in enhancing the Atkinson cycle's philosophy of maximising expansion vs compression ratio. Just like our noses, bigger nostrils scientifically mean more pisai can get trapped in it. 🤣

23 hours ago, Sdf4786k said:

The same goes for small Cc engine n go mod to try to make a donkey run like a horse but end up looking like an ass when the car becomes unreliable.. of course there are the 2JZ engines that comes stock n can mod to 1000bhp but in this current era, there are few that reach that level .. like James Bond would say .. live to die another day or no time to die 😂 

@Sdf4786k Ah yes, the Jay-Z twins! 😂 There's a reason why its overengineered status has led it to become a thing of legend. I just wish we could go back to the late '80s to early 00's when the best enthusiast cars were being released; it seems like we've regressed a long way since then. 😢

22 hours ago, Unfazed said:

Wow 😮

Thanks to TS for this vid! Would be interesting to see same kinda vids for other engines too.

Now that engine would need a thorough cleanup it seems, look at the sludge buildup too.

@Unfazed No worries, I'm just sharing what I find interesting! I don't think other engines would be in such good shape after so much neglect though; it's a testament to Toyota's engineering quality, although the amount of sludge in the oil pan still haunts me though. 👻😱

22 hours ago, Unfazed said:

@Watwheels 

Thank you for this great vid too to let us know the different kind of engine Toyota is using, now i wonder does the NR series of Toyota engines in models like Vios uses the Otto cycle?

Wah....with this vid and the vid from TS, where is our Anti-T or Toyota basher when we need some healthy debates? 😆😉

Every 4-stroke engine that doesn't rely on the Atkinson cycle's method of opening the intake valve during compression is in essence an Otto-cycle engine. That being said, please don't encourage the trolls, because fanboy-ism is highly contagious and incurable once introduced into forum threads! 😷

[Toeknee_33]

On 11/10/2021 at 8:50 AM, Watwheels said:

FYI the Prius engine's combustion cycle is running on Atkinson cycle, there is also a 2.5L engine also running on Atkinson cycle in their hybrid vehicles. Most other Toyota engines are running on Otto cycle.

Go Google what is Atkinson cycle in a combustion engine and what is Otto cycle.

You cannot compare passenger cars with F1 cars. They have to meet different sets of rules. Passenger cars have to meet FC and CO2 emissions. F1 cars have to meet their F1 regulations. Not an Apple to Apple comparison.

 

Just to add on, the current range of "Dynamic Force" engines, beginning with the Camry a few years back, runs on BOTH Atkinson and Otto cycles, switching back and forth depending on driving conditions, to maximise efficiency and power.