When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Evo GeneralDiscuss any generalized technical Evo related topics that may not fit into the other forums.
Please do not post tech and rumor threads here.
Sponsored by: RavSpec - JDM Wheels Central
yea I was looking some stuff last night and finally found what I needed to know, it was more on the lines do we need to connect to the intake manifold which we do, you cannot block off the intake pcv valve to the crankcase
going to probably buy another catch can here later this week for the dual setup
yea I was looking some stuff last night and finally found what I needed to know, it was more on the lines do we need to connect to the intake manifold which we do, you cannot block off the intake pcv valve to the crankcase
going to probably buy another catch can here later this week for the dual setup
x2 on the dual catch can set up, I'm sporting the ones from Radium Engineering.
The one between the pcv & intake manifold always catches nasty gasy oily muck while the one between the valve cover & the intake is bone dry.
I mean. Catch cans are for blown engines or engines where the OEM baffle has failed for some reason. IF you are finding oil in any of the PCV hoses it usually means a clog, maintenance issue, or otherwise failure of part of the system. brand new engines from the factory never include 'catch cans' because healthy engines don't use them.
The only exception to this rule is when the OEM baffle simply isn't up to the challenge of engine modifications made. In that case, the engine is no longer original parts, and the baffle needs to be improved somehow.
That means cutting/welding/fabricating inside the OEM baffle for improvements. i.e. finding out why it is inadequate and making a modification to correct the issue.
for example in Honda engines where redline is raised and the vehicle is tracked, engine oil pools in the valve cover baffle causing liquid oil to clog the pcv hoses which leads to failure of the pcv system.
the 'fix' as terrible as it sounds was to drill a choice few holes in the baffle to allow oil to drain back to the head, solving the issue from the inside.
To install a catch can externally would only be a 'band-aid'. The reason this is not a good idea is because now you still have liquid oil traversing an orifice where oil is unwanted, i.e. taking up space inside a PCV tube, which reduces the volume (effective diameter) Of that/those tubes, thus reducing effective PCV action, and can still lead to blown oil seals and general engine failure.
I think everyone is missing the point on this post, I know what a catch can does and how to install them with hoses to the valve cover, I wanted to know if I could remove the PCV valve that was connected on the intake manifold and re route the 2 lines to the catch can directly from the valve cover.
In this case you cannot do that because the car will run extremely rough which in my case it did.Basically after searching for several hours that is unmetered air that is being circulated still "basically a boost leak"
So I went to lowes to get the barb and thread it back in, after connecting the valve cover to the intake manifold the car runs like it did before.
I was not sure if it was a pointless thing or not, but now i plan on doing 2 catch cans since the PCV valve is needed on the intake manifold
You don't want additional crankcase volume because it reduces effectiveness of PCV
You don't want any catch cans as generally when people see them (mechanics and knowledgeable folks) they will think the engine is hurt or damaged, and blowing oil
A catch can is a sign there is something wrong with the engine.
I mean. Catch cans are for blown engines or engines where the OEM baffle has failed for some reason. IF you are finding oil in any of the PCV hoses it usually means a clog, maintenance issue, or otherwise failure of part of the system. brand new engines from the factory never include 'catch cans' because healthy engines don't use them.
The only exception to this rule is when the OEM baffle simply isn't up to the challenge of engine modifications made. In that case, the engine is no longer original parts, and the baffle needs to be improved somehow.
That means cutting/welding/fabricating inside the OEM baffle for improvements. i.e. finding out why it is inadequate and making a modification to correct the issue.
for example in Honda engines where redline is raised and the vehicle is tracked, engine oil pools in the valve cover baffle causing liquid oil to clog the pcv hoses which leads to failure of the pcv system.
the 'fix' as terrible as it sounds was to drill a choice few holes in the baffle to allow oil to drain back to the head, solving the issue from the inside.
To install a catch can externally would only be a 'band-aid'. The reason this is not a good idea is because now you still have liquid oil traversing an orifice where oil is unwanted, i.e. taking up space inside a PCV tube, which reduces the volume (effective diameter) Of that/those tubes, thus reducing effective PCV action, and can still lead to blown oil seals and general engine failure.
Considering that if you put a catch can on a brand new EVO it will fill up with nasty gunk I reject your premise that only "blown engines" or "engines with failed baffles" need them. The Mitsubishi Starion came from the factory with a catch can setup... but it was designed to empty back into the oil pan rather than being emptied by the owner at each oil change... a horrible error with the kind of nasty crap you get in a catch can.
In short, if you have an EVO in any form and don't have a catch can, the inside of your intake manifold is coated in crap, most of it from the PCV system.
Considering that if you put a catch can on a brand new EVO it will fill up with nasty gunk I reject your premise that only "blown engines" or "engines with failed baffles" need them. The Mitsubishi Starion came from the factory with a catch can setup... but it was designed to empty back into the oil pan rather than being emptied by the owner at each oil change... a horrible error with the kind of nasty crap you get in a catch can.
In short, if you have an EVO in any form and don't have a catch can, the inside of your intake manifold is coated in crap, most of it from the PCV system.
Keith
If the oil returns to the pan, then it isn't a catch can. I know exactly what you are talking about because sr20det 2.0L turbo engines from 1989 to 1994 have the same exact OEM piece, a "black can" that isn't a can, it simply drains back to the oil pan. They did this in that era because Valve cover baffles were not yet up the challenge of separating oil and air properly (early 90's it was a challenge I guess for engines running 20psi+ of boost to keep all their oil inside). Then in 1995 they eliminated it completely and just use 1 hose from the valve cover to the turbo intake from that point onwards, for all turbo engines, not just SR20 but Nissans all famous RB series and Toyota 2JZ series all had adequate baffles since 95 to not need such a piece. 1995. 1995.
What you are saying is that Mitsubishi engineers never figured out how to design an oil baffle. That they came all the way from 80's to now, and managed to create the only 2.0L 4-cylinder turbo that doesn't have a properly designed oil baffle. That the engineers still can't figure that out and it needs a catch can device immediately.
I would rather choose to believe that the engineers designed the 2.0L perfectly in all aspects including crankcase baffle system, and that nothing needs to be added or done here. Just properly maintain it and pull a little harder whenever you can on it (vacuum pumps and higher seals, custom designs which improve it are fine). A small amount of oil flow is expected when intake manifold driven pcv but most of it should stop in the baffle. The minute you start to see oil, and complain about oil showing up, now we need numbers. We need to know exactly how much pressure in the crankcase and atmosphere under these conditions and we do this with a sensor logging at a high rate reading crankcase pressure in small increments as 0.1" H2O.
If you came to me with a $9999999 race car and complained about oil flow in the intake manifold, this is where we immediately go. There is no catch can lol. You put a sensor on the expensive engine and it will reveal how to proceed in crankcase system/oil evacuation containment.
And the other extreme:
If we adjust the car price to $0.00001 or free. Now the use of such equipment is laughable. Nobody will spend $5 on a car worth less than $0.000000001. So what can we do for free and how can we diagnose for free. A can is the cheapest option, more or less for "free". Obviously in reality we can use things like leakdown tests and compression tests but if the car is truly so cheap, maybe those tools are out of reach as well. All we can do is look, listen, and go from there, I am just setting up our possible actions to fix the issue. So lets ask what is the root cause first:
The root cause of crankcase pressure is easy to pinpoint: pressure which inappropriately leaves the combustion chamber or intake air pathway and enters the crankcase.
That is what I might call a seal failure, or damaged seal. Seals not doing their jobs.
If we can take apart the engine and examine the sealing surfaces (ex piston rings) we might find the engine was run with a poor quality air filter, or no air filter, and there is damage to the sealing surfaces. This is probably one root cause of high blow-by in OEM high mileage performance engines. The air contains several hundred thousand particulate or some ridiculous amount to even consider letting it inside a device with compresses and burns any mixture and is made of metal. Anyways- usually the root cause is a maintenance issue, somebody modified or failed to maintain seals. It seems like the highest mileage engines would not be coincidentally linked to the use of original airbox components and oem filters, as it directly influences damage to the physical parts of a working machine. The highest quality OEM imported engines always contain updated original airbox and pcv equipment.
So root cause in factory engine is damaged piston rings or similar damaged internal oil/air seals.Considering where the pressure comes from which we did. Or poorly designed. Its either actually poorly designed, or, its damaged, and I just can't believe that its poorly designed.
So diagnose, fix? Whats the easiest thing to do. Install a can to catch whatever is blowing out. The catch can is the easiest thing to do, to bandaid and keep driving the engine and try to forget that something is wrong and it is blowing oil.
In my mind, the less of these hoses and connections I see, the less corrective measuring I see on the engine, especially on the surface where you can see it from the bay(nevermind the hidden special device engineered to fully contain high output necessary oilflow), is a sign that there is trouble with oil flow, that the owner is struggling with the flow of oil emanating from the engine in some capacity. That the oil system has something wrong with it.
Therefore, the engine bay with the fewest visible measures taken is the one that I am interested in.
That there is a careless dismissal of the very notion that oil might come flying out anywhere is laughable.
The fact you can connect a 'catch can' to any engine and suddenly start collecting 'nasty junk' is irrelevant. That happens because of the way the can is installed, it does not happen during the engine's normal operation or the factory would have taken notice. An improperly installed additional crankcase volume will be subjected to non-crankcase like conditions, i.e. stagnant collection of water and oil. During normal operating conditions water is driven off by the high temperature of engine oil, which will not happen to oil that sits collected in a container on the side of the engine.
I can add an external, stagnant oil reservoir to any engine and see that same 'nasty stuff' building up over time. It doesn't mean the engine is bad or good, it just happens because of the changing temperature and water vapor in the air coming and going as oil heats and then cools, nearby in the crankcase to which it is connected apparently.
A healthy engine should never have a catch can. If oil mist or vapor is noticably entering the intake manifold on an engine with 000500 miles or similar (brand new) then it means the oil baffle was improperly designed. Or working as intended. Some oil flow may be expected and maybe they did measure it and found that it didn't really hurt anything. In sr20 applications there is always a little bit oil residue on the insides of turbocharger inlet plumbing, but the tube is convoluted in such a way that the majority of the mess made from 120,000 miles of driving is trapped in the intake tube, where I come along 20 years later and wash it once with degreaser to get it back to new looking, and then maintain it by washing it out once in a while as part of a routine schedule. I find hard to believe on an engine such as 4G63 considering how well it is designed, how often they are turbo, how long its been around, that the oil control is lacking. It is far more likely that the owners simply lack the attention to detail required to maintain the PCV systems and gradually make it worse by adding all these external components and fail to maintain whats already there. I've never had an engine, non turbo or otherwise, with good piston ring seal (good compression, air filter) that needed some kind of catch device.
Last edited by KingTal0n; May 5, 2019 at 03:07 PM.
If the oil returns to the pan, then it isn't a catch can. I know exactly what you are talking about because sr20det 2.0L turbo engines from 1989 to 1994 have the same exact OEM piece, a "black can" that isn't a can, it simply drains back to the oil pan. They did this in that era because Valve cover baffles were not yet up the challenge of separating oil and air properly (early 90's it was a challenge I guess for engines running 20psi+ of boost to keep all their oil inside). Then in 1995 they eliminated it completely and just use 1 hose from the valve cover to the turbo intake from that point onwards, for all turbo engines, not just SR20 but Nissans all famous RB series and Toyota 2JZ series all had adequate baffles since 95 to not need such a piece. 1995. 1995.
What you are saying is that Mitsubishi engineers never figured out how to design an oil baffle. That they came all the way from 80's to now, and managed to create the only 2.0L 4-cylinder turbo that doesn't have a properly designed oil baffle. That the engineers still can't figure that out and it needs a catch can device immediately.
I would rather choose to believe that the engineers designed the 2.0L perfectly in all aspects including crankcase baffle system, and that nothing needs to be added or done here. Just properly maintain it and pull a little harder whenever you can on it (vacuum pumps and higher seals, custom designs which improve it are fine). A small amount of oil flow is expected when intake manifold driven pcv but most of it should stop in the baffle. The minute you start to see oil, and complain about oil showing up, now we need numbers. We need to know exactly how much pressure in the crankcase and atmosphere under these conditions and we do this with a sensor logging at a high rate reading crankcase pressure in small increments as 0.1" H2O.
If you came to me with a $9999999 race car and complained about oil flow in the intake manifold, this is where we immediately go. There is no catch can lol. You put a sensor on the expensive engine and it will reveal how to proceed in crankcase system/oil evacuation containment.
And the other extreme:
If we adjust the car price to $0.00001 or free. Now the use of such equipment is laughable. Nobody will spend $5 on a car worth less than $0.000000001. So what can we do for free and how can we diagnose for free. A can is the cheapest option, more or less for "free". Obviously in reality we can use things like leakdown tests and compression tests but if the car is truly so cheap, maybe those tools are out of reach as well. All we can do is look, listen, and go from there, I am just setting up our possible actions to fix the issue. So lets ask what is the root cause first:
The root cause of crankcase pressure is easy to pinpoint: pressure which inappropriately leaves the combustion chamber or intake air pathway and enters the crankcase.
That is what I might call a seal failure, or damaged seal. Seals not doing their jobs.
If we can take apart the engine and examine the sealing surfaces (ex piston rings) we might find the engine was run with a poor quality air filter, or no air filter, and there is damage to the sealing surfaces. This is probably one root cause of high blow-by in OEM high mileage performance engines. The air contains several hundred thousand particulate or some ridiculous amount to even consider letting it inside a device with compresses and burns any mixture and is made of metal. Anyways- usually the root cause is a maintenance issue, somebody modified or failed to maintain seals. It seems like the highest mileage engines would not be coincidentally linked to the use of original airbox components and oem filters, as it directly influences damage to the physical parts of a working machine. The highest quality OEM imported engines always contain updated original airbox and pcv equipment.
So root cause in factory engine is damaged piston rings or similar damaged internal oil/air seals.Considering where the pressure comes from which we did. Or poorly designed. Its either actually poorly designed, or, its damaged, and I just can't believe that its poorly designed.
So diagnose, fix? Whats the easiest thing to do. Install a can to catch whatever is blowing out. The catch can is the easiest thing to do, to bandaid and keep driving the engine and try to forget that something is wrong and it is blowing oil.
In my mind, the less of these hoses and connections I see, the less corrective measuring I see on the engine, especially on the surface where you can see it from the bay(nevermind the hidden special device engineered to fully contain high output necessary oilflow), is a sign that there is trouble with oil flow, that the owner is struggling with the flow of oil emanating from the engine in some capacity. That the oil system has something wrong with it.
Therefore, the engine bay with the fewest visible measures taken is the one that I am interested in.
That there is a careless dismissal of the very notion that oil might come flying out anywhere is laughable.
The fact you can connect a 'catch can' to any engine and suddenly start collecting 'nasty junk' is irrelevant. That happens because of the way the can is installed, it does not happen during the engine's normal operation or the factory would have taken notice. An improperly installed additional crankcase volume will be subjected to non-crankcase like conditions, i.e. stagnant collection of water and oil. During normal operating conditions water is driven off by the high temperature of engine oil, which will not happen to oil that sits collected in a container on the side of the engine.
I can add an external, stagnant oil reservoir to any engine and see that same 'nasty stuff' building up over time. It doesn't mean the engine is bad or good, it just happens because of the changing temperature and water vapor in the air coming and going as oil heats and then cools, nearby in the crankcase to which it is connected apparently.
A healthy engine should never have a catch can. If oil mist or vapor is noticably entering the intake manifold on an engine with 000500 miles or similar (brand new) then it means the oil baffle was improperly designed. Or working as intended. Some oil flow may be expected and maybe they did measure it and found that it didn't really hurt anything. In sr20 applications there is always a little bit oil residue on the insides of turbocharger inlet plumbing, but the tube is convoluted in such a way that the majority of the mess made from 120,000 miles of driving is trapped in the intake tube, where I come along 20 years later and wash it once with degreaser to get it back to new looking, and then maintain it by washing it out once in a while as part of a routine schedule. I find hard to believe on an engine such as 4G63 considering how well it is designed, how often they are turbo, how long its been around, that the oil control is lacking. It is far more likely that the owners simply lack the attention to detail required to maintain the PCV systems and gradually make it worse by adding all these external components and fail to maintain whats already there. I've never had an engine, non turbo or otherwise, with good piston ring seal (good compression, air filter) that needed some kind of catch device.
1. Does a catch can on a new EVO catch stuff? Yes
2. Is it enough to cause a warranty repair within the warranty time frame? No
A catch can on any engine will 'catch stuff'. That isn't a reason to add one lol.
"hey if I put a stagnant reservoir externally to the warming, environmentally exposed lubrication supply for a machine which smashes and burns carbon in the presence of suitable oxygen source, it catches stuff"
You know, its quite a statement. But you have to ask yourself what was the point of doing that.
"Why did you add an external pointless reservoir, just to catch the wispy ends of daily operating and cooldown procedures? Where components condense and form all manner of bonds (covalent, hydrogen, hydrophobic, they all conglomerate) and atomic size versus circulatory status becomes irreverent (since it cannot flow through any 'filters' there is a mass of unknown/any size being formed, similar to an Embolism in the human body capable of being re-introduced to the blood stream (or oil system). This is why all factory 'catch' devices are in reality circulation improvers, they bring the oil back to the oil pan and create safe haven for hard forming carbon conglomerates which form due to negligence after 10-20 years depending on maintenance of factory pcv and air filtration.
