IO have never seen a post where 50-60000 mile engines w/o catch cans are compared to same mileage with catch cans to prove it does anything. On some VW forums it is reported the cans made no difference.
Catch Cans...
- Thread starter wemay
- Start date
- Status
wemay
Site Donor 2023
Originally Posted By: ffhdriver
IO have never seen a post where 50-60000 mile engines w/o catch cans are compared to same mileage with catch cans to prove it does anything. On some VW forums it is reported the cans made no difference.
By far, most of the vw enthusiast websites I've gleaned, agree it works.
"The Humble Mechanic" Trusted VW Tech/Mechanic on youtube.
IO have never seen a post where 50-60000 mile engines w/o catch cans are compared to same mileage with catch cans to prove it does anything. On some VW forums it is reported the cans made no difference.
By far, most of the vw enthusiast websites I've gleaned, agree it works.
"The Humble Mechanic" Trusted VW Tech/Mechanic on youtube.
Originally Posted By: Linctex
Originally Posted By: Olas
The biggest problem with catch cans fitted inline with the PCV is that they still allow combusted gas into the cylinder, increasing charge temperature and displacing A/F mix.
If you calculate the HUGE volume of air flowing through an engine,
And compare that in relation to the teeny tiny bit of air going through the PCV valve....
You'd probably retract your statement.
............................
It sounds a LOT MORE like you are describing "Exhaust Gas Re-circulation" (EGR) ... NOT pcv
It's not about the volume of air as much as the idea of introducing non-combustible blowby from the crank case into the cylinder. All that should enter the cylinder is air and fuel.
Would you be happy to eat a small chunk of poop if it was only one ten thousandth Of your total yearly food intake?
The volume or percentage is irrelevant, it shouldn't be going in there at all!
Originally Posted By: Olas
The biggest problem with catch cans fitted inline with the PCV is that they still allow combusted gas into the cylinder, increasing charge temperature and displacing A/F mix.
If you calculate the HUGE volume of air flowing through an engine,
And compare that in relation to the teeny tiny bit of air going through the PCV valve....
You'd probably retract your statement.
............................
It sounds a LOT MORE like you are describing "Exhaust Gas Re-circulation" (EGR) ... NOT pcv
It's not about the volume of air as much as the idea of introducing non-combustible blowby from the crank case into the cylinder. All that should enter the cylinder is air and fuel.
Would you be happy to eat a small chunk of poop if it was only one ten thousandth Of your total yearly food intake?
The volume or percentage is irrelevant, it shouldn't be going in there at all!
Originally Posted By: spasm3
Could a catch can also be used to dose some solvent to the intake valves? Perhaps after its empty some b-12 or techron added to the can?
No, you're thinking of an inverse oiler.
Could a catch can also be used to dose some solvent to the intake valves? Perhaps after its empty some b-12 or techron added to the can?
No, you're thinking of an inverse oiler.
Originally Posted By: Olas
Originally Posted By: Linctex
Originally Posted By: Olas
The biggest problem with catch cans fitted inline with the PCV is that they still allow combusted gas into the cylinder, increasing charge temperature and displacing A/F mix.
If you calculate the HUGE volume of air flowing through an engine,
And compare that in relation to the teeny tiny bit of air going through the PCV valve....
You'd probably retract your statement.
............................
It sounds a LOT MORE like you are describing "Exhaust Gas Re-circulation" (EGR) ... NOT pcv
It's not about the volume of air as much as the idea of introducing non-combustible blowby from the crank case into the cylinder. All that should enter the cylinder is air and fuel.
Would you be happy to eat a small chunk of poop if it was only one ten thousandth Of your total yearly food intake?
The volume or percentage is irrelevant, it shouldn't be going in there at all!
Yeah, but road draft tubes left us in the 1960s, and for very good reasons.
Originally Posted By: Linctex
Originally Posted By: Olas
The biggest problem with catch cans fitted inline with the PCV is that they still allow combusted gas into the cylinder, increasing charge temperature and displacing A/F mix.
If you calculate the HUGE volume of air flowing through an engine,
And compare that in relation to the teeny tiny bit of air going through the PCV valve....
You'd probably retract your statement.
............................
It sounds a LOT MORE like you are describing "Exhaust Gas Re-circulation" (EGR) ... NOT pcv
It's not about the volume of air as much as the idea of introducing non-combustible blowby from the crank case into the cylinder. All that should enter the cylinder is air and fuel.
Would you be happy to eat a small chunk of poop if it was only one ten thousandth Of your total yearly food intake?
The volume or percentage is irrelevant, it shouldn't be going in there at all!
Yeah, but road draft tubes left us in the 1960s, and for very good reasons.
Originally Posted By: Shannow
Originally Posted By: Olas
Originally Posted By: Linctex
Originally Posted By: Olas
The biggest problem with catch cans fitted inline with the PCV is that they still allow combusted gas into the cylinder, increasing charge temperature and displacing A/F mix.
If you calculate the HUGE volume of air flowing through an engine,
And compare that in relation to the teeny tiny bit of air going through the PCV valve....
You'd probably retract your statement.
............................
It sounds a LOT MORE like you are describing "Exhaust Gas Re-circulation" (EGR) ... NOT pcv
It's not about the volume of air as much as the idea of introducing non-combustible blowby from the crank case into the cylinder. All that should enter the cylinder is air and fuel.
Would you be happy to eat a small chunk of poop if it was only one ten thousandth Of your total yearly food intake?
The volume or percentage is irrelevant, it shouldn't be going in there at all!
Yeah, but road draft tubes left us in the 1960s, and for very good reasons.
Road draft tubes are the start of the perfect crankcase scavenging system - road draft tube into vac pump, vac pump outlet to a catch can and then vented to atmosphere.
Cleaner inlet, better VE, constant depression for ring seal, no vacuum leak, no valve to plug up,
PCV is oly a good idea when crossing deep water.
Originally Posted By: Olas
Originally Posted By: Linctex
Originally Posted By: Olas
The biggest problem with catch cans fitted inline with the PCV is that they still allow combusted gas into the cylinder, increasing charge temperature and displacing A/F mix.
If you calculate the HUGE volume of air flowing through an engine,
And compare that in relation to the teeny tiny bit of air going through the PCV valve....
You'd probably retract your statement.
............................
It sounds a LOT MORE like you are describing "Exhaust Gas Re-circulation" (EGR) ... NOT pcv
It's not about the volume of air as much as the idea of introducing non-combustible blowby from the crank case into the cylinder. All that should enter the cylinder is air and fuel.
Would you be happy to eat a small chunk of poop if it was only one ten thousandth Of your total yearly food intake?
The volume or percentage is irrelevant, it shouldn't be going in there at all!
Yeah, but road draft tubes left us in the 1960s, and for very good reasons.
Road draft tubes are the start of the perfect crankcase scavenging system - road draft tube into vac pump, vac pump outlet to a catch can and then vented to atmosphere.
Cleaner inlet, better VE, constant depression for ring seal, no vacuum leak, no valve to plug up,
PCV is oly a good idea when crossing deep water.
Also,
Yeah, but road draft tubes left us in the 1960s, and for very good reasons.
Look at any carbureted VW, road draft tube vents straight into airbox with no 'fresh air in' hose and no valve. And every motorbike ever.
Road draft isnt as 'long dead' as you think..
Yeah, but road draft tubes left us in the 1960s, and for very good reasons.
Look at any carbureted VW, road draft tube vents straight into airbox with no 'fresh air in' hose and no valve. And every motorbike ever.
Road draft isnt as 'long dead' as you think..
Originally Posted By: Olas
Would you be happy to eat a small chunk of poop if it was only one ten thousandth Of your total yearly food intake?
careful there or we will start talking about the bugs and excrement we actually do eat
Originally Posted By: Olas
Road draft tubes are the start of the perfect crankcase scavenging system - road draft tube into vac pump, vac pump outlet to a catch can and then vented to atmosphere.
and the power for the vac pump comes from?
Would you be happy to eat a small chunk of poop if it was only one ten thousandth Of your total yearly food intake?
careful there or we will start talking about the bugs and excrement we actually do eat
Originally Posted By: Olas
Road draft tubes are the start of the perfect crankcase scavenging system - road draft tube into vac pump, vac pump outlet to a catch can and then vented to atmosphere.
and the power for the vac pump comes from?
Battery or alternator, or a belt. Is there an option I've missed?
Back to the poop analogy - waste is waste, it shouldn't go back in. Anybody disagree?
Back to the poop analogy - waste is waste, it shouldn't go back in. Anybody disagree?
Originally Posted By: Linctex
Originally Posted By: Olas
The biggest problem with catch cans fitted inline with the PCV is that they still allow combusted gas into the cylinder, increasing charge temperature and displacing A/F mix.
If you calculate the HUGE volume of air flowing through an engine,
And compare that in relation to the teeny tiny bit of air going through the PCV valve....
You'd probably retract your statement.
............................
It sounds a LOT MORE like you are describing "Exhaust Gas Re-circulation" (EGR) ... NOT pcv
The numbers don't lie. There are MILLIONS of cars and trucks without catch cans. And yet they run just fine. Our last van sold with half a million miles, did not consume oil at any measurable rate between OCI's, no smoke, no drips, and it had no catch can. How can this be when you hear all the ridiculous analogies?
If you have tons of blow by and poor sealing then you will have lots of oily vapor flowing through your PCV. If you have a normal running car then you may have a slightly cleaner intake tract. But it's a classic case of "want" versus "need".
Originally Posted By: Olas
The biggest problem with catch cans fitted inline with the PCV is that they still allow combusted gas into the cylinder, increasing charge temperature and displacing A/F mix.
If you calculate the HUGE volume of air flowing through an engine,
And compare that in relation to the teeny tiny bit of air going through the PCV valve....
You'd probably retract your statement.
............................
It sounds a LOT MORE like you are describing "Exhaust Gas Re-circulation" (EGR) ... NOT pcv
The numbers don't lie. There are MILLIONS of cars and trucks without catch cans. And yet they run just fine. Our last van sold with half a million miles, did not consume oil at any measurable rate between OCI's, no smoke, no drips, and it had no catch can. How can this be when you hear all the ridiculous analogies?
If you have tons of blow by and poor sealing then you will have lots of oily vapor flowing through your PCV. If you have a normal running car then you may have a slightly cleaner intake tract. But it's a classic case of "want" versus "need".
Originally Posted By: Olas
Road draft tubes are the start of the perfect crankcase scavenging system - road draft tube into vac pump, vac pump outlet to a catch can and then vented to atmosphere.
Cleaner inlet, better VE, constant depression for ring seal, no vacuum leak, no valve to plug up,
PCV is oly a good idea when crossing deep water.
I have nearly this exact setup, except:
Tube > Catch Can > Vac Pump > Airbox
You want the catch can before the vac pump if you are using an electric smog pump for a vac pump like I am. With a traditional race car belt driven pump, you want the catch can after, because race style pumps are lubricated by the oil mist that they capture.
I have never found any evidence of oily deposits either in the air box, or the air filter. Can wipe any part with the finger, and it's dry as a bone.
No stink, no harm to the environment, and if there is any adverse effect on power, it has surely been made up for by the vacuum on the crankcase. The pumps move enough air that I have been able to allow a little fresh air inlet to the crankcase without losing any vacuum, so I also get the full benefits of a PCV system.
Road draft tubes are the start of the perfect crankcase scavenging system - road draft tube into vac pump, vac pump outlet to a catch can and then vented to atmosphere.
Cleaner inlet, better VE, constant depression for ring seal, no vacuum leak, no valve to plug up,
PCV is oly a good idea when crossing deep water.
I have nearly this exact setup, except:
Tube > Catch Can > Vac Pump > Airbox
You want the catch can before the vac pump if you are using an electric smog pump for a vac pump like I am. With a traditional race car belt driven pump, you want the catch can after, because race style pumps are lubricated by the oil mist that they capture.
I have never found any evidence of oily deposits either in the air box, or the air filter. Can wipe any part with the finger, and it's dry as a bone.
No stink, no harm to the environment, and if there is any adverse effect on power, it has surely been made up for by the vacuum on the crankcase. The pumps move enough air that I have been able to allow a little fresh air inlet to the crankcase without losing any vacuum, so I also get the full benefits of a PCV system.
wemay
Site Donor 2023
Originally Posted By: SteveSRT8
...But it's a classic case of "want" versus "need".
Yup, and i want it. It's simple, i don't want the blow-by byproduct muck reintroduced into the engine. As explained in the video below, the reason it isn't standard is because its another maintenance item responsibility in a world where getting consumers to change their oil on time is challenging enough...
...But it's a classic case of "want" versus "need".
Yup, and i want it. It's simple, i don't want the blow-by byproduct muck reintroduced into the engine. As explained in the video below, the reason it isn't standard is because its another maintenance item responsibility in a world where getting consumers to change their oil on time is challenging enough...
I'm not a huge fan of what is known as a "catch can". The design we know as "catch can" was basically designed to keep exiting fluids from ending up on a race track surface and does precious little to remove oil vapor out of the air stream.
That which is known as a CCV or "crankcase filter" tends to be ridiculously better at the job.
CCVs and CCFs have been nearly a mandatory and standard part of diesel engines (the original direct injected engine) pretty much since the first second diesel engines started ingesting their own crankcase gases. This is the fact that flies right in the face of those who claim that "OEM does not use them" and "If they did anything, the OEM would use them". They do, in a major way.
If you're serious about removing oil from the crankcase gases, the one to use is this style:
This is used on a LOT of diesel engines, straight from the OEM. You can wipe the outlet tube with a white glove on these engines and not find oil deposited. The media used there removes the oil vapor and returns it to a liquid state.
This is NOT a "catch can" however. It is absolutely not intended to store oil. The nipple at the bottom is a drain, designed to return oil to the crankcase. You would have to either have that drain go down into a separate oil reservoir, or devise a way for it to drain back to the crankcase. The inlet and outlet are also very large. You would need to step down the inlet and outlet to the sizes you need to use through adapters.
Sounds like a pain to deal with, but that CCV right there is the last word on removing oil from the crankcase discharge. The air returning to your engine will be dry.
That which is known as a CCV or "crankcase filter" tends to be ridiculously better at the job.
CCVs and CCFs have been nearly a mandatory and standard part of diesel engines (the original direct injected engine) pretty much since the first second diesel engines started ingesting their own crankcase gases. This is the fact that flies right in the face of those who claim that "OEM does not use them" and "If they did anything, the OEM would use them". They do, in a major way.
If you're serious about removing oil from the crankcase gases, the one to use is this style:
This is used on a LOT of diesel engines, straight from the OEM. You can wipe the outlet tube with a white glove on these engines and not find oil deposited. The media used there removes the oil vapor and returns it to a liquid state.
This is NOT a "catch can" however. It is absolutely not intended to store oil. The nipple at the bottom is a drain, designed to return oil to the crankcase. You would have to either have that drain go down into a separate oil reservoir, or devise a way for it to drain back to the crankcase. The inlet and outlet are also very large. You would need to step down the inlet and outlet to the sizes you need to use through adapters.
Sounds like a pain to deal with, but that CCV right there is the last word on removing oil from the crankcase discharge. The air returning to your engine will be dry.
Originally Posted By: Linctex
Originally Posted By: spasm3
Could a catch can also be used to dose some solvent to the intake valves? Perhaps after its empty some b-12 or techron added to the can?
It would never be distributed evenly - one or two valves might see the whole dose, while the others get none.
I just wonder if the solvent distribution would be different than the oil vapor from the pvc. Would there be any potential harm i dosing like this?
Originally Posted By: spasm3
Could a catch can also be used to dose some solvent to the intake valves? Perhaps after its empty some b-12 or techron added to the can?
It would never be distributed evenly - one or two valves might see the whole dose, while the others get none.
I just wonder if the solvent distribution would be different than the oil vapor from the pvc. Would there be any potential harm i dosing like this?
Originally Posted By: wemay
Originally Posted By: SteveSRT8
...But it's a classic case of "want" versus "need".
Yup, and i want it. It's simple, i don't want the blow-by byproduct muck reintroduced into the engine. As explained in the video below, the reason it isn't standard is because its another maintenance item responsibility in a world where getting consumers to change their oil on time is challenging enough...
I am a firm believer in folks being able to mod their cars in almost any way they desire.
I just don't like folks telling others that they must mod the way they did just "because"! While a catch can helps you believe that the car will run better it is highly unlikely to do anything noticeable.
Originally Posted By: SteveSRT8
...But it's a classic case of "want" versus "need".
Yup, and i want it. It's simple, i don't want the blow-by byproduct muck reintroduced into the engine. As explained in the video below, the reason it isn't standard is because its another maintenance item responsibility in a world where getting consumers to change their oil on time is challenging enough...
I am a firm believer in folks being able to mod their cars in almost any way they desire.
I just don't like folks telling others that they must mod the way they did just "because"! While a catch can helps you believe that the car will run better it is highly unlikely to do anything noticeable.
wemay
Site Donor 2023
Originally Posted By: SteveSRT8
I am a firm believer in folks being able to mod their cars in almost any way they desire.
I just don't like folks telling others that they must mod the way they did...
I hope you're not insinuating that I'm telling others to do this because i have. Because that's not the case. But there's also a distinction between being a snob about your mods and explaining why you belive a certain mod works for you. Doing so without being a knucklehead is key.
I am a firm believer in folks being able to mod their cars in almost any way they desire.
I just don't like folks telling others that they must mod the way they did...
I hope you're not insinuating that I'm telling others to do this because i have. Because that's not the case. But there's also a distinction between being a snob about your mods and explaining why you belive a certain mod works for you. Doing so without being a knucklehead is key.
Originally Posted By: SteveSRT8
If you have tons of blow by and poor sealing then you will have lots of oily vapor flowing through your PCV. If you have a normal running car then you may have a slightly cleaner intake tract.
And everything in between. Shall those seeing shades of grey call it needed wants? Maybe time is an issue so a judgement call to determine the vehicle's expected or desired length of service with or without would be appropriate? Oh wait - that's a want, not a need! Maybe we only really "need" the car until next week...
If you have tons of blow by and poor sealing then you will have lots of oily vapor flowing through your PCV. If you have a normal running car then you may have a slightly cleaner intake tract.
And everything in between. Shall those seeing shades of grey call it needed wants? Maybe time is an issue so a judgement call to determine the vehicle's expected or desired length of service with or without would be appropriate? Oh wait - that's a want, not a need! Maybe we only really "need" the car until next week...
Originally Posted By: DoubleWasp
If you're serious about removing oil from the crankcase gases, the one to use is this style:
Not finding it in the usual online places, eBay, Amazon - Got a link?
If you're serious about removing oil from the crankcase gases, the one to use is this style:
Not finding it in the usual online places, eBay, Amazon - Got a link?
Originally Posted By: SteveSRT8
If you have tons of blow by and poor sealing then you will have lots of oily vapor flowing through your PCV. If you have a normal running car then you may have a slightly cleaner intake tract. But it's a classic case of "want" versus "need".
I totally get what you are saying Steve, but i think a lot of interest here is for DI engines. That's my interest.
If you have tons of blow by and poor sealing then you will have lots of oily vapor flowing through your PCV. If you have a normal running car then you may have a slightly cleaner intake tract. But it's a classic case of "want" versus "need".
I totally get what you are saying Steve, but i think a lot of interest here is for DI engines. That's my interest.
Originally Posted By: UberArchetype
Originally Posted By: DoubleWasp
If you're serious about removing oil from the crankcase gases, the one to use is this style:
Not finding it in the usual online places, eBay, Amazon - Got a link?
I found it on amazon , provent 200. Its not cheap.
https://www.amazon.com/Mann-Hummel-62575...eywords=provent
The only issue i see, is you have to have a collection can as well, unless you make the oil outlet a road draft tube. I don't know if an open leak in the pvc system will set a code.
Originally Posted By: DoubleWasp
If you're serious about removing oil from the crankcase gases, the one to use is this style:
Not finding it in the usual online places, eBay, Amazon - Got a link?
I found it on amazon , provent 200. Its not cheap.
https://www.amazon.com/Mann-Hummel-62575...eywords=provent
The only issue i see, is you have to have a collection can as well, unless you make the oil outlet a road draft tube. I don't know if an open leak in the pvc system will set a code.
Last edited:
- Status
Similar threads
