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Discussion Starter #1 (Edited)
I have uploaded a quick video using a borescope showing the inside of cylinder 1 of my 12' cruze eco with 300k miles.


I see normal carbon buildup I also see an area where I believe the injector spray is being focused. Each of the four cylinder pistonheads have this same "clean" area on the exact same side. I have just recently used an entire tank full of amsoil pi. I would say unless it cleans other parts of the fuel system just cleaning this small area on the pistonhead seems uncessary.



Despite the carbon buildup im still acheiveing above average mpg and engine power is still as strong as its ever been.


Here is the link.

Cylinder 3 https://www.youtube.com/watch?v=LXuqWRvhIdY&feature=youtu.be

Cylinder 1 https://www.youtube.com/watch?v=OYJV1KGoh20
 

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Yeah I clicked on just one, haha. Thanks for updating it.

As I noted on the Facebook group, you have the carbon build-up coming off only on one side of the piston, which happens to be the same side of the piston that the intake valves are on. As a result, it shouldn't surprise you to hear that after you ran AMSOIL PI through one tank of gas, the cleaner hits that side of the piston directly. Remember that the valve comes in at an angle and the air charge is redirected by the valve onto the combustion chamber and onto that specific edge of the piston. That's why you're seeing so much of the carbon build-up cleaned off in that area and not everywhere else. A few more runs of PI and you'll start to see more and more of the build-up coming off.
 

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I posted about Seafoam every oil change/plug regap. Left out only 42K miles and part of the reason I did it is I'm on coil pack #3

Pics look different than what I saw in person(focus sucks) but that little dark ring is all I saw after cleaning it.

 

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Discussion Starter #7
if your curious about getting a glimpse of the combustion chamber usb borescopes are inexpensive and they connect to any desktop or laptop using a usb.

im considering using an eye drop of cleaner and dropping onto the piston head.
 

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That's amazingly clean after 300,000 miles. Do I need to update your 250,000 badge?
 

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if your curious about getting a glimpse of the combustion chamber usb borescopes are inexpensive and they connect to any desktop or laptop using a usb.

im considering using an eye drop of cleaner and dropping onto the piston head.
I don't know what results you would get with that approach as I've never tried it. I would personally just continue using it in the gas tank but I do know that some shops use PI in their induction cleaner systems for what it's worth.
 

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Discussion Starter #11
Yeah Im a little hesitant about putting any liquid directly onto the piston even if its a small amount. I probably wont end up trying it.

I was looking at other videos of pistonheads and even though my pistonheads are covered with buildup its not nearly as bad as some of the buildup on the other pistonheads i was looking at. I know they didnt have nearly the same amount of miles I have. At 300k i would say those pistonheads are in decent condition. The buildup isnt oily or greasy buildup it looks to be a relativly thing layer.



Im assuming amsoil pi did what its designed to do cleaning other parts of the fuel system but trying to clean the entire pistonhead seems impossible. If it just cleans that one part of the pistonhead it doesnt seem like it does much good. I understand fuel cleaners are designed to help prevent rather then completely clean.
 

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Just for my education, why is a completely clean piston head desired? Sure too much junk is bad. And at least on a gasser, you don't want hot build-up causing pre-ignition. But what's the downside to a light build-up? Seems to me it would provide a bit of insulation for the piston and keep it cooler. Just as long as it doesn't keep building, is there a problem?
 

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Discussion Starter #13
From what I understand its the opposite.....less buildup or none is keeps the chamber cooler. This is normal buildup im happy with the way it looks. If I can get a cleaner piston by using more amsoil I will otherwise im content with the way it is.
 

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From what I understand its the opposite.....less buildup or none is keeps the chamber cooler.
I wouldn't call that opposite - "insulation" causing a hotter chamber but cooler parts makes sense to me. It does change the way the heat flows. It might affect efficiency, but I generally favor longer engine life over peak efficiency. So I'm curious as to what the long-term affects are.
 

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Yeah Im a little hesitant about putting any liquid directly onto the piston even if its a small amount. I probably wont end up trying it.

I was looking at other videos of pistonheads and even though my pistonheads are covered with buildup its not nearly as bad as some of the buildup on the other pistonheads i was looking at. I know they didnt have nearly the same amount of miles I have. At 300k i would say those pistonheads are in decent condition. The buildup isnt oily or greasy buildup it looks to be a relativly thing layer.

Im assuming amsoil pi did what its designed to do cleaning other parts of the fuel system but trying to clean the entire pistonhead seems impossible. If it just cleans that one part of the pistonhead it doesnt seem like it does much good. I understand fuel cleaners are designed to help prevent rather then completely clean.
On another 1.4T engine, AMSOIL PI cleaned about 60% of the surface of the piston on the first application (engine had about 35k miles using Shell fuel). However, you haven't used a truly good top end cleaner for a long time and you have 300k miles now, so there was a lot of build-up to clean. You can't expect miracles out of one bottle, especially when the manufacturer recommends treatment every 4k miles. Using top tier fuel does help, which is why I said you could probably go up to 10k miles. The problem with making conclusions about how the piston looks now is that you don't know what it looked like before the PI treatment. How do you know it didn't look as bad as the others you've seen? As you can see from the video, the build-up is pretty thick on some parts of the piston.

Just for my education, why is a completely clean piston head desired? Sure too much junk is bad. And at least on a gasser, you don't want hot build-up causing pre-ignition. But what's the downside to a light build-up? Seems to me it would provide a bit of insulation for the piston and keep it cooler. Just as long as it doesn't keep building, is there a problem?
A completely clean piston head is not absolutely necessary, but deposits do cause the formation of hot spots. Hot spots cause knock, which significantly reduces engine efficiency, particularly at heavy loads with high intake air temps. I'm referring to stop and go traffic with A/C on and you needing to get out of your way very quickly. Those are the conditions during which these deposits will start making a significant difference. Light build-up is not going to harm anything, but where do you draw the line? At what point does build-up become "too much?" Sure, you don't need the piston to be absolutely spotless, but will you be pulling your spark plugs every 10k miles to check how bad it gets before using a product to clean them? If my understanding is correct, top tier fuel was used in this engine.

I wouldn't call that opposite - "insulation" causing a hotter chamber but cooler parts makes sense to me. It does change the way the heat flows. It might affect efficiency, but I generally favor longer engine life over peak efficiency. So I'm curious as to what the long-term affects are.
Long term effects also include the wearing of piston rings due to build-up around the edge of the piston. This is actually a very common issue with Northstar V8 engines, which are never run hot enough to get the deposits burned out on a regular basis (old people). These often become oil burners because the deposits start to cause problems. The combustion chamber is a notably bigger issue than the piston is, however, as that's where the deposits are most likely to generate hot spots.

Fortunately, we have an engine that is extremely good at responding to knock, but on older engines, these build-ups can cause a lot of problems with pre-ignition due to the aforementioned hot spots.
 

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Long term effects also include the wearing of piston rings due to build-up around the edge of the piston. This is actually a very common issue with Northstar V8 engines, which are never run hot enough to get the deposits burned out on a regular basis (old people).
Yet another reason why a low-mileage (city) car might be a worse choice than a high-mileage (highway) car.
 
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