PCV Catch Can - keeps your engine clean, which helps gas mileage in the long run.

[Matt Timion]

Author:Timion, Matt

Publication:www.gassavers.org (http://www.gassavers.org)

The PCV Catch can is more of a preventative measure than an actual gas mileage booster. Here is what it is, how here is how to make one yourself.

PCV tube stands for the Positive Crankcase Ventilation tube (PCV). It's used to vent any pressure built up in the head of the engine, but since we have emissions laws, that venting means that the gasses must be properly burned to prevent excess pollution. This is done by sending the gasses back into the engine through the intake. When this occurs not only will the engine have a pushing pressure, the intake will also have a sucking action working on the tube. This results in a force so great that gasses AND oil will be transferred from the engine and into the intake manifold. In other words, it results in burning oil.

What's bad about burning a little oil? As oil gets sucked in, the throttle body, intake manifold, cold start fuel injector, and T-VIS butterflies develop a thick oily residue which coats everything it touches. When the tiny particles of dust and dirt that make it past the air filter come in contact with that oil, they bond together making a thick sludge. In the most severe cases, this can lead to the complete failure of the T-VIS system when the butterflies get so gunked up they can no longer open and close properly. The bad part about getting the throttle body dirty in particular is that it has sensors within it that contribute to the info the ECU needs to properly run the engine. Those sensors can't operate properly if they're covered in an oily residue. I'm not certain how bad it is for the cold start fuel injector, but I'm fairly certain the injector wasn't designed to operate while covered in crap.

The solution is to clean the throttle body, injectors, and intake manifold periodically to insure that the oil residue is removed, or you can remove the oil BEFORE it enters into the throttle body/intake manifold. This can be done using a PCV catch can.

A PCV catch can lies between in one of two locations. It lies between the PCV valve and the air intake manifold, or between the cylinder head cover and the air intake. I have heard of both of these instances working. Some people install the catch can on both tubes to ensure that no oil is getting through to the throttle body. The PCV catch can filters the air and seperates the oil out of the air. The basic theory behind the catch can is best illustrated here:

http://www.gassavers.org/files/gassavers/pvc_catchcan0.jpg


There are a few methods of how to construct such a device. It all depends on how many "around the house" objects you want ot use, or how nice you want it to look. The best construction I have seen uses an water filter that is used in air compression tools. They can be found in Home Depot, Lowes, or other hardware stores. One resource recommended Campbell Hausfeld part #MP513810. Any water filter made for air compressors should work.

http://aircompressorsdirect.com/catalog/images/MP513810_400.jpg


The first thing to do is to remove the small filter screen inside the filter. It is not needed for our application, and leaving it in could cause a buildup of oil to clog the filter. Next wrap thread lock around the fittings that you will eventually screw onto the filter. When this is done you will either cut the hose you want the filter on and install it at the break in the hose, or you will buy a new hose to prevent damaging your old one. Some people use longer hoses in order to be able to mount the filter on the firewall.

You end product should look like this:

http://www.gassavers.org/files/gassavers/pvc_catchcan1.jpghttp://www.gassavers.org/files/gassavers/pvc_catchcan2.jpghttp://www.gassavers.org/files/gassavers/pvc_catchcan3.jpghttp://www.gassavers.org/files/gassavers/pvc_catchcan4.jpg



The catch can needs to be cleaned every once in a while, which can be done by unscrewing the glass receptical and pouring out the oil. The frequency at which you are required to empty it depends entirely on your engine and the amount of oil being sent through the filter.

------------------------
Some text and ideas were taken from the following sites:
http://www.hyundaiperformance.com/forums/topic.php?t=46353
http://members.shaw.ca/migsman/AE86info/PCVInfo/PCVInfo.html



Another way to make a more "homemade" version of this device can be found here:

http://www.totse.com/en/fringe/fringe_science/pcv.html

[philmcneal]

I have people saying that, "its good to rip up your engine once in awhile to get rid of the crap inside your engine." With this PCV catch can I will never have a reason to do that ever again.

[SVOboy]

I love my little filter jar, it's got a lot of oil in it already, :p

[philmcneal]

i was wondering if there was any argument to this


catch cans won't catch everything there is

any sort of chemical leaves residue, including cleaners
bad stuff that leaves out the exhaust would leave residue in it's passage. such as the exhaust valves

iirc, for pcv valves, people just dump that in to the opening with the breathers


he and i were arguing about keeping your engine clean. He says a pcv catch can can't catch the dirty crap that redlining an engine can do. Hm....

[n0rt0npr0]

I'm with him that the catch can cannot be compared to the occasional "rip-on-it" technique. You have to keep the bottom/back of the intake and exhaust valves clear and clean someway.

[rh77]

I'm with him that the catch can cannot be compared to the occasional "rip-on-it" technique. You have to keep the bottom/back of the intake and exhaust valves clear and clean someway.

I enjoy using both methods (the rip-it, of course rarely, but sometimes mentally necessary) -- and it helps the car :D

RH77

[SVOboy]

I think you do need to push it every so often, just to keep things loose, but I think it's fairly obvious a pcv catch can will be catching things.

[philmcneal]

is it ok to rip it up if my oil is filled between the max and min lines? Bleh I don't even like WOT acceleration anymore, how much (as in RPMS wise) must I do to keep this baby clean?

[SVOboy]

Just take it to redline once or twice a blue moon, *shrug*

[n0rt0npr0]

In my experiance, the only way you can keep your engine clean without "rippin it up" is driving them nice lean-burn hwy miles. When you do a lot of "throttling" such as in city stop and go driving, the engine is more apt to enrich the fuel/air mixture.

Then IF you stop(read:turn off engine) and you were running rich, the CC is more coated in fuel than with the more lean-burn hwy mode. That coating slowly forms deposits as the vehicle cools, and later on turns to carbon as the volatile components evaporate.

Another way to keep overly rich fuel out of the CC is to have an O2 that works good (read: a newer 02)

[rh77]

I have PCV catch devices on both of my vehicles, and they collect a significant amount of gunk that would otherwise be burned and gunk-up the works (I used Matt's how-to from this site, and it only takes 10 minutes -- all parts are included in a kit -- it's basically the device that collects moisture on home air-compressors). The normal carbon build-up could be blown-through with a good revving to get the vacuum levels up, and intake air through: that is until the next Seafoam or AutoRx Cleanse.

BTW - I like the new Avatar n0rt0npr0! The Celebrity was a decent car. The EuroSport Version was a lot of fun - a good friend had one a while back until someone totalled it (I see you have some suspension parts from that series). I got to know the GM 60-Degree V-6 quite a lot when my family was GM-only. I loved my new '95 Beretta (Level II) with the newer 3.1L, that was until it broke several times under warranty -- so I figured I'd dump it before the warranty ran out. At the time, I really wanted the '96 Impala SS (Caprice with the Corvette Engine and Cop-Car parts). RWD just didn't work well in the gravel and snow, so I stuck with FWD. One of the biggest mistakes Chevy made was to dump the Corsica/Beretta line in '96 and not really replace it with anything close. Oh well, their loss...

RH77

[n0rt0npr0]

Yes Matt and SVO have done some awesome how-to's that plane.

I am a 60°V6 enthusiast. I've put over 350 thousand miles on these engines. Something GM did right from the beginning regarding the PCV catch can idea: They made the crankcase vent system long enough to reduce the high velocity that carries "misted" oil and gunk particles to the intake. Meaning, never have I had to clean the intake out to specifically delete gunk from the throttle plate and vaccuum passages. All my oil/gunk drains into a groove in the intake hosing.(think a ribbed home vaccuum hose)

Anyway, all I do is use a paper towel to wipe out those grooves every 50,000 miles. I should take pictures of how its set up to do this next time I am at the 50k mark.

Yes I have found gunk/varnish on the very BACK of the throttle plate once BUT that was only because I held off in fixing the original problem and it escalated.

That gunk/oil that your PCV catch can gets, has very very very little to do with carbon build-up... in my opinion. And Thanks for the props on the avatar rick:)

[molecule]

hydrocarbons from superheated oil dispersed out of the block by pressure (or the lack thereof) actually will burn quite easily...
catching the gunk solids and allowing the airborne hydrocarbons to pass into the engine is beneficial...

remember its all oil...just in different states...

say NO to gunk

[mikefxu]

I am sure your 02 and cat don't like oil.

[philmcneal]

ok ok fine i'll drop by home depot and see how magical this pcv catch can really is, bleh wish me luck and hope i don't fry my engine! i think i have 20000 miles on my car so maybe there's tons of gunk build up waiting for me already? hmmm

[93dagsr]

is there any way to filter the part that goes back into the intake with a filter that isn't all that dense? can you move that little filter it comes with to the intake side?

[93dagsr]

home depot:

http://www.homedepot.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=10051&langId=-1&catalogId=10053&productId=100027474&N=10000003+90401&marketID=401&locStoreNum=8125

^unit^

http://www.homedepot.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=10051&langId=-1&catalogId=10053&productId=100000128&N=10000003+90401&marketID=401&locStoreNum=8125

^male adapter^

lowes:

http://www.lowes.com/lowes/lkn?action=productDetail&productId=221024-1126-KBA10600AV&lpage=none

http://www.lowes.com/lowes/lkn?action=productDetail&productId=221014-1126-KBA10800AV&lpage=none

http://www.lowes.com/lowes/lkn?action=productDetail&productId=221018-1126-KBA11000AV&lpage=none

^unit^

has anyone tried one of these filters instead of the one that comes with it??

http://www.lowes.com/lowes/lkn?action=productDetail&productId=23367-15649-PPFV150-B&lpage=none

^filter^

http://www.lowes.com/lowes/lkn?action=productDetail&productId=154979-15649-PPXLMA9125&lpage=none

^male adapter^

[1fixitman]

http://i252.photobucket.com/albums/hh11/1fixitman/PCVjarcompleteweb.jpg
Here is the PCV jar mod that I placed in my 2005 Toyota Prius.
Note that I removed the entire stock air box on the passenger side of the engine
compartment just behind the headlight.
The copper coils have engine coolant flowing thru them to heat the jar to remove
most of the liquid content in the form of vapor. The heated coolant comes from the
throttle body on the cool side so as not to steal any heat from the throttle body preheat.
The vapors flow thru a V8 can inside of the jar that is packed with copper bb's.
There is a piece of metal screen at the top and bottom of the V8 can to keep the bb's
from ever entering the vaccum line although it would be almost impossible for the vaccum
in that line to suck up bb's from the bottom of the jar. The threaded metal stock was
purchased at a local lamp shop. I cut them to length with a hack saw. The copper coil
adds heat to the process to vaporize any liquids and to help break down any vaporous
HC's in the mixture before being sucked back into the throttle body. It works great but
took more time than the standard air compressor water remover from the hardware store.

Dwayne

[bowtieguy]

anyone got any hard #s supporting a significant increase using the PCV catch?

[aalb1]

anyone got any hard #s supporting a significant increase using the PCV catch?

Because this is a mod for the long haul its kind of hard to slap on a catch can and look at the scanguage and do some A-B B-A testing within a week.

Something for comparison is that guy who cleaned out his EGR ports on his CRX HF. With a catch can from the start he may never have needed to do this cleaning or at least not as bad as quick.

I don't have EGR ports on my civic but I'm pretty damn sure that my intake manifold has a gooey mess of vaporized oil build up on its walls.:(

[suspendedhatch]

No alteration to the PCV system will save you from having to periodically remove and clean out the EGR ports. The hot exhaust gases cool rapidly on their way to the intake forming carbon deposits.

The PCV catch can in this thread will only catch a small portion of the residue. To be effective, you need to build a baffled catch can with a decent filter element. Steel wool is commonly used in these DIYs but it turns out that it's not an effective filter element. Neither are fuel filters.

You'll still need to periodically remove and clean the throttle body and intake manifold. Also, a lot of that mess coating your intake actually comes through your air filter and from your Evap purge.

Burning oil vapors effectively lowers the octane rating of the fuel in the combustion chamber.

[theholycow]

I wonder if cleaning the EGR ports, throttle body, and intake manifold is listed in maintenance schedules. Is it something I should do on my 180,000 mile old GMC?

[bowtieguy]

holycow,

i'm not a mechanic, but i typically do those things as part of routine maintenance(every 1 to 2 years).

just an experience...

i had a saturn throw an EGR code once. after pricing them, i decided to pull it off and clean it. put in a good fuel system cleaner as well, and never saw the code again(drove it for more than a year before trading it).

[suspendedhatch]

No, it's not listed. I can't speak to GM engines but I would say that if it's not too much trouble you should take off your intake tube, prop the throttle open, and peer into your intake manifold with a flashlight, maybe reach around inside with a white glove LOL.

On a Honda it makes a big difference. You need to change the gaskets, remove the injectors and clean out their ports, clean off the IAT, clean out the MAP port, the IACV and it's ports, the PCV valve, the Evap port (leaves a grease hill on your throttle body mating surface), and clean the throttle blade. Then you take the intake manifold to a place that has a parts cleaner. After 15 years those runners are coated in thick deposits of yummy black gravy.

[Daveedo]

I completely rebuilt an eagle talon motor last year and it had about 1/8" thick crud on the throttle body and close to 3/8" inside the intake. It looked and felt like that dirty caked oil you get on leaky old motors...but it was INSIDE the intake:thumbdown: I can definitely see how this buildup over time can affect air flow, atomization(spray pattern of the injectors), and possibly power/mileage. I suppose if someone had a really crusted up intake/throttle body they could check mileage then clean it and check mileage again. Provided testing procedures were identical it would give us an idea of any difference that may occur. VERY small sample size for only one person to do it so it'd be nice to see several experiments.

btw, a motor that is in good shape should not be blowing/sucking hardly any oil through the pvc valve. If it is then a catch can is an option. Alot of guys with DSMs put them in their cars too.

[suspendedhatch]

That sounds just like every Honda that I have ever owned. Surprisingly most of the deposits are formed by particles that pass through your air filter.

I don't know if you'll see a significant change in FE but it does effect your emissions measurably.