PCV Catch Can ?

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LH23H2R

LH23H2R

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I'm certain that this topic has been brought up an untold number of times , but here it goes again ...

I've been thinking more and more about PCV Catch Cans , and potentially adding one to my '72 Coronet .
It behooves me to know that motor oil is coking-up the heat crossover in the intake ( a friend of mine did the 'burn & scrape' to it 2 years ago when we replaced the head gaskets . That sucker was absolutely plugged all to hell ! ) , which , to me , is highly inefficient in operation !

Now , are PCV Catch Cans a streetable addition ?

How many of you here have a PCV C.C. on your street motors ?

Are they effective ?

Are they a ***** to make via DIY ?

Thanks much . Pics of your Catch Cans would be great !
 
I have only seen them used with vacuum pumps.How would this connect to the heat crossover?
 
WTF is a "PCV catch can"? the oil belongs BACK IN THE CRANKCASE, not in some "catch can"
 
It goes between the pcv in the valve cover and the intake manifold. They are supposed to separate any oil vapor from combustible vapor before it goes back into the intake manifold to be burned. I don't think it would hurt to add one. A lot of people put them on the new Hemi engines, they like to burn a lot of oil through the pcv for some reason. You could make one or buy them some are expensive.
 
JGC403 said:
It goes between the pcv in the valve cover and the intake manifold. They are supposed to separate any oil vapor from combustible vapor before it goes back into the intake manifold to be burned. I don't think it would hurt to add one. A lot of people put them on the new Hemi engines, they like to burn a lot of oil through the pcv for some reason. You could make one or buy them some are expensive.
Click to expand...

But it goes into the intake not the crossover.
 
the PCV is the reason why oil cokes-up the heat crossover . It's supposed to ventilate back-into the induction via the carb's base's ported-vacuum ; it's a closed-system .

By-and-large , PCV is a good thing . It originated in 1961 ( Ca. ; 1962 in the other 49 states ) as "CCV" and was an open-system , relatively speaking . It took the place of Road Draft Tubes .

Granted , if one's car is driven at expressway speeds for a reasonable amount of time , and the engine is completely warmed-up to operating temperature , the oil-coking is minimalised , but a problem never-the-less .

I just wanted to know if the PCV oil catch can was a streetable endevour .
Seems like it is , even though it originated in race applications .

I don't know about you , but I'd like to avoid having the intake manifold's heat crossover getting plugged with carbon ( unburned oil ) .
 
JGC403 said:
It goes between the pcv in the valve cover and the intake manifold. They are supposed to separate any oil vapor from combustible vapor before it goes back into the intake manifold to be burned. I don't think it would hurt to add one. A lot of people put them on the new Hemi engines, they like to burn a lot of oil through the pcv for some reason. You could make one or buy them some are expensive.
Click to expand...

OK, I get it , it's a vapor/ oil separator, then drains the condensate back into the valve cover/ crankcase. Actually, that has some merit. I can see that a fire -breathin- high RPM engine might just pump some vapor past the PCV at times.
 
67Dart273 said:
WTF is a "PCV catch can"? the oil belongs BACK IN THE CRANKCASE, not in some "catch can"
Click to expand...

This is a complete misnomer. If oil is getting past the PCV, its being burned in the engine. It doesn't go back into the crankcase if its already gotten past the PCV.

PCV catch cans are nothing new. They don't replace the PCV, they go into the line between the PCV and the carb/throttle body/intercooler plumbing. Look into any turbocharged car and you'll see them used quite a bit. They're not that hard to make, depending on how complicated you want to get. I've even seen them made out of water traps made for air compressors (although, you have to be picky, most of those are made out of plastics that will melt with oil contact).

The reason you see them used on turbocharged cars is pretty simple, PCV valves were intended to work under vacuum. If your vacuum system also works under boost, you can run into problems with your PCV, namely, oil blowing past it. In turbocharged applications, it can actually be quite a bit of oil. I ran a PCV catch can on my Dodge SRT-4 (a 230hp turbocharged 2.4L Neon for those that don't know), it would fill up on a fairly regular basis and need to be drained. Before the catch can, oil would actually drip from the joints of my intercooler tubing onto my driveway.

On a NA engine, I doubt you'd be talking about a significant amount of oil. But, there is oil in that vapor, and it will coat the inside of the PCV hose.

So, yes, you can run a PCV catch can on a street car. Easy.

But, I don't think your problem is oil from the PCV. Heat crossovers get filled with exhaust fumes. The particulates tend to stay there, and they coke up. Every heat crossover I've ever seen come off a car has had a pretty significant amount of blockage from carbon coking up in it. Obviously, the cleaner your engine runs the longer your crossover will stay clean. But the small amount of oil from the PCV is probably not your main contributor. You probably get more oil past your valve seals and rings, even in a rebuilt engine. If your PCV system is really pushing that much oil into your engine, then you have other problems.

And finally- your heat crossover being plugged up is not causing some huge performance or efficiency problem. Most higher performance intakes don't even have them (ie, air gap manifolds), because after they've done you the favor of warming your carb up to operating temperature, they keep heating that sucker up. Cold fuel is more efficient, it just makes your car harder to start/warm up when its cold.

At any rate, here's one of the "higher end" ones for a SRT-4
http://www.modernperformance.com/catch-0305-neon-srt4-p-2061.html

And here's an example of home built. All you really need to see is on the front page. And, it does work. Maybe not the best, but actually functional.

http://www.srtforums.com/forums/f75/how-another-catch-can-install-97923/
 
I'd argue the PCV cokes up the heat crossover. Most likely culprit would be the wore out valve guides, rock hard valve seals or missing seals. If your getting blow-by from the PCV breather, you can always run a hose down to the exhaust collector and install a anti-backfire valve and tube. Moroso sells the kit. Does your valve cover shield the PCV valve? 25900 is the part number.
 
72bluNblu said:
This is a complete misnomer. If oil is getting past the PCV, its being burned in the engine. It doesn't go back into the crankcase.

PCV catch cans are nothing new. They don't replace the PCV, they go into the line between the PCV and the carb/throttle body/intercooler plumbing. Look into any turbocharged car and you'll see them used quite a bit. They're not that hard to make, depending on how complicated you want to get. I've even seen them made out of water traps made for air compressors (although, you have to be picky, most of those are made out of plastics that will melt with oil contact).

The reason you see them used on turbocharged cars is pretty simple, PCV valves were intended to work under vacuum. If your vacuum system also works under boost, you can run into problems with your PCV, namely, oil blowing past it. In turbocharged applications, it can actually be quite a bit of oil. I ran a PCV catch can on my Dodge SRT-4 (a 230hp turbocharged 2.4L Neon for those that don't know), it would fill up on a fairly regular basis and need to be drained. Before the catch can, oil would actually drip from the joints of my intercooler tubing onto my driveway.

On a NA engine, I doubt you'd be talking about a significant amount of oil. But, there is oil in that vapor, and it will coat the inside of the PCV hose.

So, yes, you can run a PCV catch can on a street car. Easy.

But, I don't think your problem is oil from the PCV. Heat crossovers get filled with exhaust fumes. The particulates tend to stay there, and they coke up. Every heat crossover I've ever seen come of a car has had a pretty significant amount of blockage from carbon coking up in it. Obviously, the cleaner your engine runs the longer your crossover will stay clean. But the small amount of oil from the PCV is probably not your main contributor. You probably get more oil past your valve seals and rings, even in a rebuilt engine. If your PCV system is really pushing that much oil into your engine, then you have other problems.

Here's one of the "higher end" ones for a SRT-4
http://www.modernperformance.com/catch-0305-neon-srt4-p-2061.html

And here's an example of home built. All you really need to see is on the front page. And, it does work. Maybe not the best, but actually functional.

http://www.srtforums.com/forums/f75/how-another-catch-can-install-97923/
Click to expand...

This is what I was saying. Its not getting thru the intake.Pcv valve has nothing to do with the crossover.
 
72bluNblu : Thanks much for the detailled explanation behind the function of PCV , and how it applies to Turbo / Super Charged and Naturally-Aspirated motors :glasses8: .

The application I'm persuing is for the stock , high-mileage 318 in my daily driver 1972 Coronet . It's going to be some time before I can afford to rebuild / replace the motor , so I was looking for a way to rectify the blow-by in the interm .

The car sees ~30 miles of freeway driving , five days a week , plus lots of local , around town driving ; total of ~100 miles weekly .

Like I said , the crossover was 'scraped & burned' in May 2009 , so it's still pretty clean . I have the stock automatic choke hooked-up and functioning ; and I have no problems with cold operation ( I let the motor warm-up for at least 2 minutes @ fast idle , then s-l-o-w-l-y drive it until the t-stat opens ) .

Thanks again for everyone's input , replies , opinions and welcomed elabourations :mrgreen:
 
daredevil said:
This is what I was saying. Its not getting thru the intake.Pcv valve has nothing to do with the crossover.
Click to expand...

For the most part you're right, and it shouldn't be a big contributor. But, if oil vapor is getting past the PCV, it is being burned and that will add to the carbon coking up in the crossover.

LH23H2R said:
72bluNblu : Thanks much for the detailled explanation behind the function of PCV , and how it applies to Turbo / Super Charged and Naturally-Aspirated motors :glasses8: .

The application I'm persuing is for the stock , high-mileage 318 in my daily driver 1972 Coronet . It's going to be some time before I can afford to rebuild / replace the motor , so I was looking for a way to rectify the blow-by in the interm .

The car sees ~30 miles of freeway driving , five days a week , plus lots of local , around town driving ; total of ~100 miles weekly .

Like I said , the crossover was 'scraped & burned' in May 2009 , so it's still pretty clean . I have the stock automatic choke hooked-up and functioning ; and I have no problems with cold operation ( I let the motor warm-up for at least 2 minutes @ fast idle , then s-l-o-w-l-y drive it until the t-stat opens ) .

Thanks again for everyone's input , replies , opinions and welcomed elabourations :mrgreen:
Click to expand...

No problem! If you have a high mileage car it is possible that your PCV is getting more oil and seeing more pressure than it should be. Probably not your biggest contributor, but, you can still give it a try.

Check out that second link I sent. It's not the greatest catch can, its really too small for that. But, it will show you if oil is getting past your PCV, so as a cheap test its not a bad idea. If you find it fills up quickly, you know where you need to spend some time working on things, or that spending more money on a better catch can might be warranted.
 
I see what you are trying to do now. Maybe find an old auto ac dryer and hose clamp it in between the pcv and the carb. Cheap and effective.
 
Mr Hemi said:
I'd argue the PCV cokes up the heat crossover. Most likely culprit would be the wore out valve guides, rock hard valve seals or missing seals. If your getting blow-by from the PCV breather, you can always run a hose down to the exhaust collector and install a anti-backfire valve and tube. Moroso sells the kit. Does your valve cover shield the PCV valve? 25900 is the part number.
Click to expand...

I'm with you Mr H. The amount of oil being dispersed through the PCV is less than what's already in the chamber that's gotten past rings, valve guides, and seals. By itself the PCV can't do it... That is unless the rest of the engine is trashed (which would have already plugged the passage due to poor ring seal, poor burning, and dried/gone valve seals and guides)
 
Would this really work if you dont have a free flowing exhaust.I have always wondered about back pressure due to mufflers and tailpipes.
 
The only reason to add an oil catch can to the PCV line is because you are trying to squeeze the last few miles out of a whipped engine pending rebuild or replacement. There is no benefit on an engine in decent mechanical condition. The heat crossover passage will accumulate carbon with or without a catch can -- for that matter, it will accumulate carbon with or without a PCV system. Stock valve covers are generally baffled to prevent oil spray off the rockers from getting sucked up the PCV valve. If your valve cover doesn't have a baffle for whatever reason, and it is a '70 or later valve cover (with twist-on oil cap) you can easily add an oil separator between the PCV valve and the valve cover -- a Ford oil cap with 1" hole in the top is the key part. Stant number 10071:

getimage.php


PCV grommet goes in the hole, PCV valve goes in the grommet. Original PCV hole in the valve cover gets a blockoff plug (make your own: get a new PCV valve grommet and fill the central hole with RTV silicone). Or, if you don't like that solution, you can use a Buick/Pontiac breather cap, Stant 10078, equipped with a Chrysler PCV valve and grommet on the opposite valve cover from the one that contains the original Mopar breather cap:

10078.jpg


Exhaust evacuation of the crankcase is race-only, not workable on streetable exhaust systems.
 
Exhaust evacuation of the crankcase is race-only, not workable on streetable exhaust systems.

What I was thinking
 
SlantSixDan : Thanks for the tip , and for providing not only p.n.'s , but pics as well !

You're right ; that 318 is tired . Didn't help any that the head gaskets blew on it a couple of years ago :mumum: . I was able to catch it in time and rectify it promptly . However , I just know that the main , rod and cam bearings took a beating ; also , lots of blow-by via the breather :( .

Eventually , my broke Blue Collar *** will be able to afford to build another 318 and slam it home over a week's vacation . Until then ...

Thanks All for Your Input , Opinions and Advice :mrgreen:
 
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