crankcase venting

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05-24-2005, 08:21 AM
Kevyd

crankcase venting

Here's a question. Is it bad to not be running a pcv valve? Right now I just have one breather on each valve cover. Just simple push in breathers. No hoses... Does this harm anything? Is a pcv valve a must? I don't think it is unless you're trying to pass a smog test but who knows??!
05-24-2005, 08:43 AM
robot

This is a common question from younger folks who dont remember the "road draft tube" engines before the Positive Crankcase Venelation arrived. There is an amount of vapor created in the crankcase.....older engines with worn rings and cylinder walls have more blowby. In the old days, the oily vapor was simply routed out of the engine by a tube. This road draft tube usually hung down under the car so the vapors would get blown away as the car ran down the road. The tube had some mesh in it so that the oil would condense and maybe go back into the engine. Those cars didnt rust underneath since they had a nice coating of oil on their underside.

Your engine without PCV is the same.....no matter how tight it is there will be vapor escaping and the valve covers will have a nice oily film on them......if you dont care, the system will work.

However, it is so easy to install a PCV, a clean engine compartment is simple.
05-27-2005, 06:36 PM
Kevyd

breather

Hmmmmm, now that you mention it.......Yeah, there is a small oily film on the valve covers. Thanks! Makes sense....
05-31-2005, 03:42 PM
47fordCOE

what if your running valve covers with no breathers.....possible probems??????
05-31-2005, 04:15 PM
lt1s10

Quote:

Originally posted by 47fordCOE
what if your running valve covers with no breathers.....possible probems??????

you got to have some kind of a breather. 2 push-ins well work, people use them all the time on round tracks at over 6000 rpms. to do it right you need to install a pcv system.

http://www.clubhotrod.com/forums/att...&postid=100112
06-09-2005, 10:44 PM
deltahomer

breathers

I'm running a 327 chevy (64) with the old breather in it. It1s10 is right ya gotta run some kind of breathing system. I saw a pic of someone who ran a pipe between valve covers with one big breather right over the water neck ! ! Whatever works ! !
06-10-2005, 03:41 AM
NTFDAY

Quote:

Originally posted by 47fordCOE
what if your running valve covers with no breathers.....possible probems??????

I had a '57 Ford custom after coming back from overseas in 66. To pass emissions in So. Cal. they plugged the 292 up in an attempt to instal a pvc system. One night it built up so much pressure it blew the dipstick out, put a dent in the hood and covered the passenger side of the windshield with oil. Shortly thereafter the bearings were toast. Engine has to breathe.
06-24-2005, 09:31 PM
R Pope

Moisture and acids, the byproducts of combustion, have to be vented out of the engine or the bearings, etc., won't last very long. Put a PCV valve in one of the tappet covers, and a vented cap in 'tother, your engine will thank you for it.
06-25-2005, 05:59 AM
hotshoe

I don't think you can effectively use the PCV valve in one valve cover with an "open" vented cap in the other. The PCV venting system only works when the engine breathes solely through the PCV valve.
06-25-2005, 03:06 PM
lt1s10

hotshoe
"I don't think you can effectively use the PCV valve in one valve cover with an "open" vented cap in the other. The PCV venting system only works when the engine breathes solely through the PCV valve".

it has to be open somewhere else on the motor or you would suck every gasket you have out of the motor. this is the open and closed system. it has to be one or the other.

http://www.clubhotrod.com/forums/att...&postid=100112
06-25-2005, 05:57 PM
lt1s10

still denny a closed system is not a system with the pcv vale in one valve cover and no openings anywhere else. on the closed system the other hose goes into the breather and circulate the air into the carb. breather. some of it get used over again and some goes out of the tail pipe, but its got to have a out let. i think some people belive a closed system would be just a pcv valve stuck in ome valve cover with no other opening. or am i reading it wromg?:HMMM:
05-24-2007, 09:10 AM
Dago Red

I know this is an old thread, but the diagram really helped me out. Thanks a lot (if that member is still around). I am supposed to dress up my uncle's truck and didn't know what exactly I was replacing in the closed PVC system, now I understand and will hopefully get the right stuff.

Red
05-24-2007, 09:13 AM
nitrowarrior

Denny, stand and take a bow.
05-24-2007, 09:23 AM
nitrowarrior

Kudos to you both.....We love your work and efforts.
05-24-2007, 05:32 PM
C9x

Some of you may find this interesting.

http://www.jalopyjournal.com/forum/s...d.php?t=184387
05-25-2007, 08:24 AM
viking

1 Attachment(s)

Open systems huh :3dSMILE:
05-25-2007, 11:05 AM
C9x

Very nice Viking.

Well thought out, looks great.
05-25-2007, 08:33 PM
viking

Sprit type cars have been running this type set up for years. :cool:
05-26-2007, 09:42 AM
Don Dalton

Quote:

Originally Posted by DennyW

Your welcome Red. Yes, all of us are still here, trying to help. :)

DENNY,TALK TO ME.

SINCE FINISHING THE 34 406 SBC.,750 CFM HOLLEY AUTOMATIC SECONDARIES ,I HAVE NOTICED A SMALL OIL PUDDLE IN THE GARAGE AT THE REAR OF THE ENGINE.THE ENGINE HAS 350 MILES ON IT (BREAKING IN).I HAVE EACH ROCKER COVER VENTED WITH AN EDELBROCK BREATHER THAT HAS A SMALL PLASTIC WASHABLE FILTER INSIDE.DO YOU THINK THE BREATHERS ARE CAUSING THE LEAK ? IS THE LEAK NORMAL FOR BREAK IN ON A PERFORMANCE ENGINE. I CHECKED THE PAN SCREWS AND THEY APPEAR TO BE OK. I DID CHANGE OUT THE PAN FROM ORIGINAL TO ALUMINUM FINNED.

DON IN AUSTIN
05-26-2007, 10:02 AM
Don Dalton

Denny Thanks

Don In Austin
05-30-2007, 06:42 PM
eticket

Hooking up your PCV

One thing I would like to add is that be careful where you hook up your PCV for your vacum source. On Fords you sometimes have an opening off one of the runners. That would not be a good idea as now you stand a chance of running that one cylinder lean. Your PCV needs to be hooked to a full time vacum source, but I have been told not to tee it into your vacum brake line, never was given a reason, but I figured it had something with messing with the vacum needed for the brakes, so that was good enough for me.

and as a side note about the size of your PCV
http://performanceunlimited.com/documents/pcvfact.html

Mike
05-30-2007, 09:29 PM
Blow by

I also had the same issue as Kevyd and have now gone to a pcv valve with great results.Took me a while to figure out,unfortunately I was not a member of this forum at the time.Has kept my rocker covers a lot cleaner and runs just fine.Hence my screen name.Live and Learn.:D
05-31-2007, 08:22 AM
Don Dalton

Quote:

Originally Posted by eticket

One thing I would like to add is that be careful where you hook up your PCV for your vacum source. On Fords you sometimes have an opening off one of the runners. That would not be a good idea as now you stand a chance of running that one cylinder lean. Your PCV needs to be hooked to a full time vacum source, but I have been told not to tee it into your vacum brake line, never was given a reason, but I figured it had something with messing with the vacum needed for the brakes, so that was good enough for me.

and as a side note about the size of your PCV
http://performanceunlimited.com/documents/pcvfact.html

Mike

ETICKET: IN MY EARLIER REPLY I STATED THAT I WAS ONLY RUNNING EDELBROCK BREATHERS WITH WASHABLE FILTERS. IS THIS A BAD IDEA? I DON'T HAVE A PVC HOOK UP.I SAW THE ILLUSTRATION DENNY POSTED (PCV)AND IT LOOKED AWESOME.

DON IN AUSTIN
05-31-2007, 08:27 AM
Don Dalton

Quote:

Originally Posted by Don Dalton

ETICKET: IN MY EARLIER REPLY I STATED THAT I WAS ONLY RUNNING EDELBROCK BREATHERS WITH WASHABLE FILTERS. IS THIS A BAD IDEA? I DON'T HAVE A PVC HOOK UP.I SAW THE ILLUSTRATION DENNY POSTED (PCV)AND IT LOOKED AWESOME.

DON IN AUSTIN

OOPS'''''''' PCV NOT POLYVINYLCHLORIDE (PVC)

DON IN AUSTIN