Catch Can Full
01-13-2018, 06:54 PM
#41
New Member
Your getting off topic here bra. I appreciate all the drawings but I wasn't looking to get into semantics regarding pcv systems and oil catch cans and I certainly don't need to be "at a full understanding", or at least what you believe to be a full understanding of the pcv system.
The oil in the pipes of the fi guys is not due to turbo seals blowing out. I was actually thinking about what I read a couple months back from oldman350z and it was regarding superchargers, the pcv system and preventing oil from getting into the intercooler piping.
All b.s. aside, if you have a catch can and it's vented, you no longer have a positive crankcase ventilation system so ditch the can, put a filter on both the valve covers and call it a day or, with all the oil that's being caught, pull the dipstick and extend the hose that was going to the catch can and shove it into the dip stick opening. Recycling.
The oil in the pipes of the fi guys is not due to turbo seals blowing out. I was actually thinking about what I read a couple months back from oldman350z and it was regarding superchargers, the pcv system and preventing oil from getting into the intercooler piping.
All b.s. aside, if you have a catch can and it's vented, you no longer have a positive crankcase ventilation system so ditch the can, put a filter on both the valve covers and call it a day or, with all the oil that's being caught, pull the dipstick and extend the hose that was going to the catch can and shove it into the dip stick opening. Recycling.
01-14-2018, 06:22 AM
#42
New Member
You just gave him terrible advice again. Recycling will not work. That would pressurize the crankcase. You should look at the "schemantics" some more before you try to advise someone.
lol honest mistake; thought schematic was misspelled
lol honest mistake; thought schematic was misspelled
Last edited by yosip1115; 01-14-2018 at 08:14 PM.
01-14-2018, 07:12 AM
#43
New Member
Sounds like your panties are getting stuck in the crack there bud. I haven't given any bad advice yet. It's actually where anyone with a little common sense would start, where the problem is most obvious and work from there, now **** off
Schemantics?
Last edited by onevq35de; 01-14-2018 at 07:13 AM.
01-14-2018, 05:44 PM
#45
Registered User
Thread Starter
The motor was replaced, I have an invoice from the shop that did the work. There is only one hose going to the catch can. Where does that driver side valve cover usually vent to?There car doesn’t really have much on it, just bolt ons. intake, exhaust, plenum spacer, oil cooler, koyo radiator, sway bad, brakes, control arms, completely gutted, caged, and safety restraints for road racing.
Last edited by Thefbomb13; 01-14-2018 at 05:47 PM.
01-14-2018, 05:55 PM
#46
New Member
Driver side to intake pipe where the pcv system draws fresh, metered air.
01-14-2018, 05:57 PM
#47
New Member
Both of the valve covers usually vent back into the intake just before the throttle body. They're connected in front and a tube goes from the back of the drivers side one to the bottom of the intake pipe
01-14-2018, 06:05 PM
#48
New Member
Gonna try to unsubscribe from this thread. Yosip buddy, you're making my nutz itch something fierce.
Both valve covers do not usually vent back into the intake. The passenger side runs from the pcv valve to the lower collector and the crank case draws air via the driver side valve cover to intake pipe.
fbomb, get a fsm and follow that before you end up getting some truly bad advice.
Yep. First time I unsub'd. VQ out !!!
Both valve covers do not usually vent back into the intake. The passenger side runs from the pcv valve to the lower collector and the crank case draws air via the driver side valve cover to intake pipe.
fbomb, get a fsm and follow that before you end up getting some truly bad advice.
Yep. First time I unsub'd. VQ out !!!
Last edited by onevq35de; 01-14-2018 at 06:08 PM.
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01-14-2018, 07:01 PM
#50
Registered User
Thread Starter
01-14-2018, 08:06 PM
#51
New Member
In terms of preventing oil lost through the PCV system (which is separate from the valve cover venting system fyi...) a vented catch can is the best option.
Is there any chance you are adding too much oil? If you're able to verify that your oil level is about mid dip stick then it sounds like you have a problem on your hands. Just do the compression test on a warm engine to be sure it isn't something else, but excessive blowby is a sign of worn piston rings.
01-16-2018, 04:24 PM
#52
Registered User
Thread Starter
You are right. You would effectively be increasing the average pressure differential by introducing vacuum; pulling more oil into the plenum than you are seeing now in the vented catch can, and you would have no way to monitor how much like you can now. I'm sure that guys posts will be edited in no time to hide all of that bs he was saying. Shame.
In terms of preventing oil lost through the PCV system (which is separate from the valve cover venting system fyi...) a vented catch can is the best option.
Is there any chance you are adding too much oil? If you're able to verify that your oil level is about mid dip stick then it sounds like you have a problem on your hands. Just do the compression test on a warm engine to be sure it isn't something else, but excessive blowby is a sign of worn piston rings.
In terms of preventing oil lost through the PCV system (which is separate from the valve cover venting system fyi...) a vented catch can is the best option.
Is there any chance you are adding too much oil? If you're able to verify that your oil level is about mid dip stick then it sounds like you have a problem on your hands. Just do the compression test on a warm engine to be sure it isn't something else, but excessive blowby is a sign of worn piston rings.
I’m definitely always putting the right amount of oil in. So we think that maybe because the PCV is still in the car it’s recirculating the blow-by gases on the passenger side thus creating more crankcase pressure in the driver side valve cover.. does that make sense? Is that possible?I don’t even know why my car still has a PCV in it at all.. should’ve taken this out when I bought the car.Also, can you tell me how to space my damn messages out? Wth lol
Last edited by Thefbomb13; 01-16-2018 at 04:28 PM.
01-16-2018, 05:02 PM
#53
New Member
I’m definitely always putting the right amount of oil in. So we think that maybe because the PCV is still in the car it’s recirculating the blow-by gases on the passenger side thus creating more crankcase pressure in the driver side valve cover.. does that make sense? Is that possible?I don’t even know why my car still has a PCV in it at all.. should’ve taken this out when I bought the car.Also, can you tell me how to space my damn messages out? Wth lol
It's pretty deceiving that the PCV valve is located on the valve cover. The PCV is routed through the valve cover, but it is completely sealed off from the valve cover's internals.
The two valve covers are attached to each other and the gasses that are expelled from them go through the drivers valve cover and into the intake before the throttle body like we discussed.
Simultaneously, the crankcase pressure (yes blowby like you said) is vented through the PCV valve, but none of this blowby ever goes into the valve covers. It's like a bulkhead fitting if you're familiar.
Excessive blowby causes a higher airflow rate through the crankcase and out of the PCV valve which takes some oil with it. In the case of the VQ, it happens to take quite a lot of oil with it as it escapes... Hence the oil "consumption" issue.
There are other factors that add to this like common leaky valve cover gaskets, and oil being burned through the rings themselves, but I believe the majority of "consumption" is due to blowby pushing oil mist out of the PCV valve. All that it takes is one time not checking the oil level and this phenomenon snowballs.
It's a real issue, mainly when you drive the car hard like we do. If you were just cruising around town, it would take a good amount of miles to rid the engine of a quart.
I have a 40k mile old longblock, I drive it hard whenever I drive it, and there is a lot of blowby when I'm boosting like CK said earlier. I push a lot of oil out of the PCV and check my level every weekend. I top it up to 3/4 of the dipstick indicator in the morning on Saturday and check it on Sunday if I drive it again. Honestly I "burn" a quarter of a quart every couple hundred miles. I have some other small leaks too; valve cover at least.
I had a high mileage engine that would produce a lot of blowby at idle... My low mileage one does not do that. That being said, I did not fill up my catch can regularly... You're dealing with a different beast here.
Do you feel a lot of air escaping from the PCV valve at idle? The rings in one cylinder were shot on my engine that I felt that on. That was the one who's compression was at 115 that I told you about. 85 on first crank, 115 in subsequent cranks...
If you had a catch can that was vented, inlet high on the can, outlet low, and breather on top, you could literally recycle like onevq said. That way it would give the blowby somewhere to go.
But again, please please please do a compression test. Warm engine. And post up the numbers. Did you always have this issue, around the time you got 170 on all cylinders, or is this new? Like I said just one slip and bye bye rings, hello blowby. More pics can't hurt if your compression test checks out OK.
I'm curious if the built block guys still have oil consumption issues. James? lol
Last edited by yosip1115; 01-16-2018 at 05:33 PM.
01-16-2018, 07:51 PM
#54
Registered User
Thread Starter
I just use the enter key when I'm typing to make paragraphs. Might be a phone glitch if you're on mobile.
It's pretty deceiving that the PCV valve is located on the valve cover. The PCV is routed through the valve cover, but it is completely sealed off from the valve cover's internals.
The two valve covers are attached to each other and the gasses that are expelled from them go through the drivers valve cover and into the intake before the throttle body like we discussed.
Simultaneously, the crankcase pressure (yes blowby like you said) is vented through the PCV valve, but none of this blowby ever goes into the valve covers. It's like a bulkhead fitting if you're familiar.
Excessive blowby causes a higher airflow rate through the crankcase and out of the PCV valve which takes some oil with it. In the case of the VQ, it happens to take quite a lot of oil with it as it escapes... Hence the oil "consumption" issue.
There are other factors that add to this like common leaky valve cover gaskets, and oil being burned through the rings themselves, but I believe the majority of "consumption" is due to blowby pushing oil mist out of the PCV valve. All that it takes is one time not checking the oil level and this phenomenon snowballs.
It's a real issue, mainly when you drive the car hard like we do. If you were just cruising around town, it would take a good amount of miles to rid the engine of a quart.
I have a 40k mile old longblock, I drive it hard whenever I drive it, and there is a lot of blowby when I'm boosting like CK said earlier. I push a lot of oil out of the PCV and check my level every weekend. I top it up to 3/4 of the dipstick indicator in the morning on Saturday and check it on Sunday if I drive it again. Honestly I "burn" a quarter of a quart every couple hundred miles. I have some other small leaks too; valve cover at least.
I had a high mileage engine that would produce a lot of blowby at idle... My low mileage one does not do that. That being said, I did not fill up my catch can regularly... You're dealing with a different beast here.
Do you feel a lot of air escaping from the PCV valve at idle? The rings in one cylinder were shot on my engine that I felt that on. That was the one who's compression was at 115 that I told you about. 85 on first crank, 115 in subsequent cranks...
If you had a catch can that was vented, inlet high on the can, outlet low, and breather on top, you could literally recycle like onevq said. That way it would give the blowby somewhere to go.
But again, please please please do a compression test. Warm engine. And post up the numbers. Did you always have this issue, around the time you got 170 on all cylinders, or is this new? Like I said just one slip and bye bye rings, hello blowby. More pics can't hurt if your compression test checks out OK.
I'm curious if the built block guys still have oil consumption issues. James? lol
It's pretty deceiving that the PCV valve is located on the valve cover. The PCV is routed through the valve cover, but it is completely sealed off from the valve cover's internals.
The two valve covers are attached to each other and the gasses that are expelled from them go through the drivers valve cover and into the intake before the throttle body like we discussed.
Simultaneously, the crankcase pressure (yes blowby like you said) is vented through the PCV valve, but none of this blowby ever goes into the valve covers. It's like a bulkhead fitting if you're familiar.
Excessive blowby causes a higher airflow rate through the crankcase and out of the PCV valve which takes some oil with it. In the case of the VQ, it happens to take quite a lot of oil with it as it escapes... Hence the oil "consumption" issue.
There are other factors that add to this like common leaky valve cover gaskets, and oil being burned through the rings themselves, but I believe the majority of "consumption" is due to blowby pushing oil mist out of the PCV valve. All that it takes is one time not checking the oil level and this phenomenon snowballs.
It's a real issue, mainly when you drive the car hard like we do. If you were just cruising around town, it would take a good amount of miles to rid the engine of a quart.
I have a 40k mile old longblock, I drive it hard whenever I drive it, and there is a lot of blowby when I'm boosting like CK said earlier. I push a lot of oil out of the PCV and check my level every weekend. I top it up to 3/4 of the dipstick indicator in the morning on Saturday and check it on Sunday if I drive it again. Honestly I "burn" a quarter of a quart every couple hundred miles. I have some other small leaks too; valve cover at least.
I had a high mileage engine that would produce a lot of blowby at idle... My low mileage one does not do that. That being said, I did not fill up my catch can regularly... You're dealing with a different beast here.
Do you feel a lot of air escaping from the PCV valve at idle? The rings in one cylinder were shot on my engine that I felt that on. That was the one who's compression was at 115 that I told you about. 85 on first crank, 115 in subsequent cranks...
If you had a catch can that was vented, inlet high on the can, outlet low, and breather on top, you could literally recycle like onevq said. That way it would give the blowby somewhere to go.
But again, please please please do a compression test. Warm engine. And post up the numbers. Did you always have this issue, around the time you got 170 on all cylinders, or is this new? Like I said just one slip and bye bye rings, hello blowby. More pics can't hurt if your compression test checks out OK.
I'm curious if the built block guys still have oil consumption issues. James? lol
I don’t drive the car much so it’s hard to tell when this issue initially happened, but after we noticed that the catch can was filling up we did a compression test and the results were decent, most of the cylinders were 180-185 and had one that was 170.. I don’t remember if the motor was cold or warm.
But I did pull off the intake manifold, and valve covers to check out the cam shafts and valves(thought we bent a valve on a miss shift but the noise was timing chain). Intake manifold gaskets weren’t that great but I reused them anyway because I wasn’t in a competitive class so I said F it, I’ll just beat the car up and rebuild it for next season. You think valve cover gasket could be a possible issue?
As for the recycling theory, you’re saying from driver side manifold to inlet/outlet into where the pcv was/is?
01-17-2018, 04:41 AM
#55
New Member
Hmmmmm very interesting. If you've compression tested after noting the catch can issue something else is up.
But no I was saying PCV valve>vented catch can> and set it up to drain the oil back into the crankcase, not the intake manifold. You would want to set it up so the oil never restricts the flow of blowby, aka having the inlet be above the outlet. It really isn't a good idea though. It's a serious bandaid, we should find the root cause.
Can you post up a video going over the entire engine bay? I've never heard of this happening if the compression is good and the oil isn't being overfilled.
The valve cove gaskets will have nothing to do with this because the PCV system is 100% separate from the valve cover oil vapor containment system
Could it be from hard right corners? Maybe someone else has had this issue on a seemingly healthy engine. In for answers
But no I was saying PCV valve>vented catch can> and set it up to drain the oil back into the crankcase, not the intake manifold. You would want to set it up so the oil never restricts the flow of blowby, aka having the inlet be above the outlet. It really isn't a good idea though. It's a serious bandaid, we should find the root cause.
Can you post up a video going over the entire engine bay? I've never heard of this happening if the compression is good and the oil isn't being overfilled.
The valve cove gaskets will have nothing to do with this because the PCV system is 100% separate from the valve cover oil vapor containment system
Could it be from hard right corners? Maybe someone else has had this issue on a seemingly healthy engine. In for answers
01-17-2018, 01:59 PM
#56
Registered User
Thread Starter
It won’t let me upload my videos.. I thought they were too long so I cut them and made em 30 seconds long and then tried posting 1 at a time but I’m having trouble..
01-20-2018, 05:48 AM
#59
New Member
Catch cans are usually run directly into the PCV valve, not the drivers side valve cover. Some have both going into it, but this is not necessary:
Drivers side valve cover is usually vented through a breather filter because almost nothing comes out of there, even at WOT. Oil vapors usually come out of there really slowly at WOT, like if you took a puff of a cigar and just opened your mouth. It just oozes. I've seen it on the dyno.
The PCV valve is another story. At WOT a lot more comes out of that (which leads me to believe the PCV valve is a direct route to the crankcase and just happens to be located on the valve cover).
Any signs that the passenger side valve cover was modified for some reason? You mentioned it a bit in the video.
That would mix PCV with valvetrain blowby; potentially taking a lot of oil from the valvetrain with it into the catchcan.
You also mentioned that the PCV valve went back into the plenum. At WOT the path of least resistance for PCV pressure could have been through the valve covers and into your catch can instead of back into the intake manifold.
What do you think
Drivers side valve cover is usually vented through a breather filter because almost nothing comes out of there, even at WOT. Oil vapors usually come out of there really slowly at WOT, like if you took a puff of a cigar and just opened your mouth. It just oozes. I've seen it on the dyno.
The PCV valve is another story. At WOT a lot more comes out of that (which leads me to believe the PCV valve is a direct route to the crankcase and just happens to be located on the valve cover).
Any signs that the passenger side valve cover was modified for some reason? You mentioned it a bit in the video.
That would mix PCV with valvetrain blowby; potentially taking a lot of oil from the valvetrain with it into the catchcan.
You also mentioned that the PCV valve went back into the plenum. At WOT the path of least resistance for PCV pressure could have been through the valve covers and into your catch can instead of back into the intake manifold.
What do you think
01-20-2018, 08:34 AM
#60
Registered User
Thread Starter
Catch cans are usually run directly into the PCV valve, not the drivers side valve cover. Some have both going into it, but this is not necessary:
Drivers side valve cover is usually vented through a breather filter because almost nothing comes out of there, even at WOT. Oil vapors usually come out of there really slowly at WOT, like if you took a puff of a cigar and just opened your mouth. It just oozes. I've seen it on the dyno.
The PCV valve is another story. At WOT a lot more comes out of that (which leads me to believe the PCV valve is a direct route to the crankcase and just happens to be located on the valve cover).
Any signs that the passenger side valve cover was modified for some reason? You mentioned it a bit in the video.
That would mix PCV with valvetrain blowby; potentially taking a lot of oil from the valvetrain with it into the catchcan.
You also mentioned that the PCV valve went back into the plenum. At WOT the path of least resistance for PCV pressure could have been through the valve covers and into your catch can instead of back into the intake manifold.
What do you think
Drivers side valve cover is usually vented through a breather filter because almost nothing comes out of there, even at WOT. Oil vapors usually come out of there really slowly at WOT, like if you took a puff of a cigar and just opened your mouth. It just oozes. I've seen it on the dyno.
The PCV valve is another story. At WOT a lot more comes out of that (which leads me to believe the PCV valve is a direct route to the crankcase and just happens to be located on the valve cover).
Any signs that the passenger side valve cover was modified for some reason? You mentioned it a bit in the video.
That would mix PCV with valvetrain blowby; potentially taking a lot of oil from the valvetrain with it into the catchcan.
You also mentioned that the PCV valve went back into the plenum. At WOT the path of least resistance for PCV pressure could have been through the valve covers and into your catch can instead of back into the intake manifold.
What do you think
Don’t you think that the catch can is essentially acting as a breather filter for the driver side valve cover? If I did have just a breather filter wouldn’t all the oil just spit into engine bay if I didn’t have a catch can? Like I said in the video I’m not sure how the car was setup after it was de-turbo’d. I’m not sure the guy even raced the car after it was repaired.I’ve taken the intake off there was no oil in the valley, the pcv hose had no oil in it as well. So I just don’t see the catch can consuming more oil if I deleted the pcv all together. What if I have blow-by in one of the even number cylinders valve stems?
Last edited by Thefbomb13; 01-20-2018 at 08:36 AM.