The Mechanics of Piston Rings and PCV Valves: Understanding Engine Oil Contamination

When it comes to understanding how an engine works, many mechanics take for granted the intricate dance between combustion, air, fuel, and oil. At the heart of this process is the piston ring, which plays a critical role in sealing the cylinder and ensuring efficient combustion. However, this same system can also introduce contaminants into the crankcase, leading to increased pressure and potentially catastrophic consequences.

As combustion occurs within the piston-cylinder device, some of the resulting gases leak past the rings and into the crankcase. This air, along with oil mist, fuel, and contaminants, creates a mixture that is then circulated throughout the engine. If blow-by pressure becomes significant for an extended duration, it can lead to increased pressure within the engine block, making it essential to have a means of releasing this excess pressure.

This is where the positive crankcase ventilation (PCV) valve comes into play. Its primary function is to allow air to escape from the crankcase, thereby reducing pressure and preventing potential damage to the engine. By rerouting this air back into the intake system, the PCV valve effectively introduces a mixture of air and contaminants into the combustion chamber.

However, this process can also lead to the formation of gunk and carbon deposits on the intake valves and Pistons, which can compromise engine performance and longevity. To mitigate this issue, an oil catch can is often employed. This device reroutes the contaminated air back into itself, capturing the oil mist and other contaminants in a separate compartment.

The design and functionality of these oil catch cans vary widely, with some models featuring simple tubes connected to a filter or baffle system. However, more advanced designs may incorporate multiple compartments, baffles, and even secondary filtration systems to ensure that only air escapes while keeping the oil contained. It is essential to select an oil catch can that effectively addresses these issues.

Some of the benefits of using an oil catch can include preventing knock or pre-ignition caused by contaminants, reducing carbon buildup on intake valves and Pistons, and minimizing the risk of engine damage due to excessive pressure. Additionally, draining the catch can periodically helps maintain its effectiveness.

Despite its benefits, there are several reasons why oil catch cans have not become a more widespread practice in the automotive industry. One major factor is cost – adding an extra component to the engine increases the overall expense. Furthermore, some mechanics may be hesitant to introduce another maintenance task into their routine, preferring to focus on simpler tasks like oil changes and filter replacements.

The case of water methanol injection systems provides a similar analogy. Like oil catch cans, these systems are designed to mitigate specific issues (in this case, engine knock caused by low-octane fuel) but require regular replenishment and maintenance to remain effective. While some vehicle manufacturers have adopted Urea injection as a standard feature, others continue to rely on simpler solutions or neglect maintenance entirely.

Ultimately, the decision to employ an oil catch can depends on individual priorities and preferences. For those who value optimal engine performance and longevity, incorporating this device into their routine may prove worthwhile. However, for those who prefer a more streamlined approach or are unwilling to introduce another maintenance task, there are alternative solutions available.

"WEBVTTKind: captionsLanguage: enhello everyone and welcome in this video we're going to be talking about what are oil catch cans what they do and how they work and so getting right into it looking here we have our engine here is our engine block within it we have the cylinder sleeve our piston connecting rod crankshaft uh things like that so here we have our engine we've got the exhaust on one side the intake on the other and in order to talk about oil catch cans we kind of need to understand blowby and for a greater explanation of how this actually works I have a video on piston rings which I get into great detail but essentially you have a combustion occur within your piston cylinder device and some of that combustion leaks past some of that air leaks past into your crank case and so that adds H pressure to this crank case and within this crank case not only do you have that air but you have kind of an oil Mist you have the contaminants that are leaking in uh the fuel perhaps and so you've got this mixture of air and oil and fuel and contaminants and things like that that are going to be mixing around within your crank case now if you have blow by a curve uh for significant duration of course you're going to build up the pressure within this engine block so you need to be able to let that pressure escape and so that's why we have a PCV valve or a positive crank case ventilation valve now that what that does is it allows that air to escape and so that air escapes what we've got here is a mixture though of air and you know oil contaminants and oil Mist uh somewhat in there and so traditionally what you'll do is you'll reroute that back to your intake so you're drawing in air from your intake this is pulling a vacuum this is is going to be at a higher pressure so it's going to draw that in and put it back into your combustion chamber well that means you're taking that oil mist and you're putting it on your intake valves you're putting on your Pistons things like that and of course you can have things build up you can have Gunk build up because of that so what an oil catch can does is you're rerouting that uh that air and those contaminants and oil and things like that into this catch can and so you can see you've got one tube coming in and that's going to drop everything in and then you've got a filter you've got baffles uh and those are going to block off that oil so that only the air can get past and then you can reroute that air back in now you're going to have different quality of oil catch cans out there so you want to make sure that there's actually something going on inside some of them will literally just have two hoses just a real cheap thing where you have one hose coming in and another hose and you're really not going to be doing all that much you want to make sure you've got uh like a filter or some baffling systems in there so that that oil can't leave and so you catch all of that oil in there uh and then that air is rerouted back in and you don't have to worry about getting Gunk uh getting that oil spraying it on your intake valves getting on your Pistons things like that and so the benefits of using something like this uh you can prevent knock or pre-ignition uh by not inserting these contaminants within there if those contaminants were to heat up uh they could cause you know different scenarios where you could have knock or preignition you can also you know try and prevent some of that carbon buildup that's going to occur on your intake valves and on your Pistons U because you're going to be rerouting that stuff so that you're no longer spraying that oil right back on top of your uh intake valve or on top of your piston uh so some good benefits of using something like this now you will have to drain this occasionally of course as it fills up with oil um and so we're going to get into kind of you know why isn't something a system like this more prevalent uh on the market and I think there's a couple of reasons uh two of the major ones being it's an added cost it's an added object that you have to throw in there and you can kind of get away with just rerouting it and burning it off um and then the other thing is you know people are lazy that's the reality of it people just don't want another maintenance task uh and having to drain this every so often would be another maintenance task so if you think about uh why water methanol never took off um which I do have a video explaining how that works uh same type of thing it's something you have to refill over time people just want to put in gas and go and forget about it uh remembering to change their oil is challenge enough and so you know similar thing with diesel Ura injection you know people don't want to add uh that Ura in order to have those injectors have the clean exhaust fluid and so that's another thing that people just kind of forget to do along with that water methanol injection so it's just another step uh that isn't necessary but it can certainly help prevent you know getting your Pistons dirty or your valves dirty uh so something that could be worthwhile doing so thank you guys for watching and if you have any questions or comments feel free to leave those belowhello everyone and welcome in this video we're going to be talking about what are oil catch cans what they do and how they work and so getting right into it looking here we have our engine here is our engine block within it we have the cylinder sleeve our piston connecting rod crankshaft uh things like that so here we have our engine we've got the exhaust on one side the intake on the other and in order to talk about oil catch cans we kind of need to understand blowby and for a greater explanation of how this actually works I have a video on piston rings which I get into great detail but essentially you have a combustion occur within your piston cylinder device and some of that combustion leaks past some of that air leaks past into your crank case and so that adds H pressure to this crank case and within this crank case not only do you have that air but you have kind of an oil Mist you have the contaminants that are leaking in uh the fuel perhaps and so you've got this mixture of air and oil and fuel and contaminants and things like that that are going to be mixing around within your crank case now if you have blow by a curve uh for significant duration of course you're going to build up the pressure within this engine block so you need to be able to let that pressure escape and so that's why we have a PCV valve or a positive crank case ventilation valve now that what that does is it allows that air to escape and so that air escapes what we've got here is a mixture though of air and you know oil contaminants and oil Mist uh somewhat in there and so traditionally what you'll do is you'll reroute that back to your intake so you're drawing in air from your intake this is pulling a vacuum this is is going to be at a higher pressure so it's going to draw that in and put it back into your combustion chamber well that means you're taking that oil mist and you're putting it on your intake valves you're putting on your Pistons things like that and of course you can have things build up you can have Gunk build up because of that so what an oil catch can does is you're rerouting that uh that air and those contaminants and oil and things like that into this catch can and so you can see you've got one tube coming in and that's going to drop everything in and then you've got a filter you've got baffles uh and those are going to block off that oil so that only the air can get past and then you can reroute that air back in now you're going to have different quality of oil catch cans out there so you want to make sure that there's actually something going on inside some of them will literally just have two hoses just a real cheap thing where you have one hose coming in and another hose and you're really not going to be doing all that much you want to make sure you've got uh like a filter or some baffling systems in there so that that oil can't leave and so you catch all of that oil in there uh and then that air is rerouted back in and you don't have to worry about getting Gunk uh getting that oil spraying it on your intake valves getting on your Pistons things like that and so the benefits of using something like this uh you can prevent knock or pre-ignition uh by not inserting these contaminants within there if those contaminants were to heat up uh they could cause you know different scenarios where you could have knock or preignition you can also you know try and prevent some of that carbon buildup that's going to occur on your intake valves and on your Pistons U because you're going to be rerouting that stuff so that you're no longer spraying that oil right back on top of your uh intake valve or on top of your piston uh so some good benefits of using something like this now you will have to drain this occasionally of course as it fills up with oil um and so we're going to get into kind of you know why isn't something a system like this more prevalent uh on the market and I think there's a couple of reasons uh two of the major ones being it's an added cost it's an added object that you have to throw in there and you can kind of get away with just rerouting it and burning it off um and then the other thing is you know people are lazy that's the reality of it people just don't want another maintenance task uh and having to drain this every so often would be another maintenance task so if you think about uh why water methanol never took off um which I do have a video explaining how that works uh same type of thing it's something you have to refill over time people just want to put in gas and go and forget about it uh remembering to change their oil is challenge enough and so you know similar thing with diesel Ura injection you know people don't want to add uh that Ura in order to have those injectors have the clean exhaust fluid and so that's another thing that people just kind of forget to do along with that water methanol injection so it's just another step uh that isn't necessary but it can certainly help prevent you know getting your Pistons dirty or your valves dirty uh so something that could be worthwhile doing so thank you guys for watching and if you have any questions or comments feel free to leave those below\n"