Valve cover / pcv question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Bamm · 03-09-2005, 07:00 PM

I am looking at this set of valve covers and I have a question. Is there anything wrong with venting the pcv/breather out the back of the valve cover? Where would you run it to? Underside of the air cleaner base? Thanks guys.....

Bamm · 03-09-2005, 07:03 PM

Sorry, here's the other pictures.

Bamm · 03-09-2005, 07:04 PM

One more.....

cdowns · 03-09-2005, 07:16 PM

you really should have baffeled covers to prevent oil being sucked into the carb

**kwmech** · 03-09-2005, 10:05 PM

Quote:

Originally Posted by cdowns

you really should have baffeled covers to prevent oil being sucked into the carb

Ditto---you will be sucking oil into the intake

**VetteVet** · 03-09-2005, 08:46 PM

Not only that all PVC systems have a check valve in them to prevent gas vapors from
getting into the oiling system, and also from overpressurizing the crankcase and blowing seals. I don't think it matters where the vent is if these two criteria are met.
I kinda like the clean look it gives.
VetteVet

Bamm · 03-09-2005, 09:24 PM

Didn't the mid-80's pontiac V-8's come off the valve covers right into the air cleaner? They just had a "clip-on" filter to keep oil from getting into the carb. Was there anything else in between there i'm missing? Thanks for the responses guys.......Jerry

72402 · 03-10-2005, 01:10 AM

Quote:

Originally Posted by Bamm 24

Didn't the mid-80's pontiac V-8's come off the valve covers right into the air cleaner? They just had a "clip-on" filter to keep oil from getting into the carb. Was there anything else in between there i'm missing? Thanks for the responses guys.......Jerry

That's the breather side where it pulls fresh air into the engine. PCV has to hook into vacuum port of intake or carburetor base.

70short/step · 03-10-2005, 08:22 AM

The best thing to do with that valve cover is to just take out that fitting and plug it. Those covers have a place that you can remove (drill or punch out) in the top of them for the oil fill and PCV valve. That was used for racing purpose and you wouldnt want to use it on a street aplication. I have been watching these and was going to bid on them and do what i said here, but If you are interested in them I will not bid. They are nice covers and would look great on an engine. Happy bidding and hope you get them.

Bamm · 03-10-2005, 11:03 AM

Is there a site somewhere that would explain the pcv system for me so I can get a handle on what is what? Thanks guys..........Jerry

70short/step · 03-10-2005, 08:49 PM

Quote:

Originally Posted by Bamm 24

Is there a site somewhere that would explain the pcv system for me so I can get a handle on what is what? Thanks guys..........Jerry

Definition: The Positive Crankcase Ventilation valve is an emissions control device that routes unburned crankcase blowby gases back into the intake manifold where they can be reburned. The PCV system is one of the oldest emission control devices, and also one of the most beneficial. Besides totally eliminating crankcase emissions as a source of air pollution, the constant recirculation of air through the crankcase helps remove moisture which otherwise would cause sludge to form. Thus the PCV valve extends the life of the oil and engine. There needs to be a fresh air supply in one valve cover so excess vacuum or pressure does not build up. Most times on a stock engine with PCV problems they clog and allow pressure to build in the crankcase which makes oil blow out the rear main and front seals as well as the valve covers.
The PCV valve requires little maintenance. The valve and filter should be replaced somewhere around 30,000 to 50,000 miles
(see the vehicle owners manual for service intervals).

Putter · 03-10-2005, 11:21 AM

I saw those on the E-bay yesteday. Looked kinda cool, BUT WHERE DOES THE OIL GET INSTALLED on oil-change day??? I aint pulling the dizzy to do that.

Bamm · 03-10-2005, 11:41 AM

Maybe the other valve cover has the oil fill? I can't remember and lost the link.
70 Short/Step - I'm not bidding on them, I just wanted to figure out how he was making that work. Reason being, I have a pair of new-in-the-box billet valve covers that don't have any holes drilled in the top and I kinda like that smooth look and was wondering if there was a way to keep that look and still have everything working as it should. Any idea's will be appreciated........Jerry

70short/step · 03-10-2005, 12:37 PM

Those valve covers that you have in the pics are Performance chevy parts and are worth about $230. Like I said before, you have to punch or drill holes in them for the oil fill and PCV valve. There are bosses in the covers to do this. If you have valve covers that have no holes for oil fill or PCV valve I do not know of any other way to vent the crankcase on a newer post 67 year. Earlier year engines had a tube in the back of the block to vent the crankcase and it just let the oil run out onto the road. The way you put oil in these older engines was the front of the intakes had a tube that stuck up with an oil cap on them. And Putter, I would pull a valve cover (if I had to) instead of the dizzy to add oil! Hope this helps you.

68LSS1 · 03-10-2005, 01:52 PM

A PCV valve isn't absolutely needed. You could run a small catch can off the AN fittings on the back of the valve covers. If you ensured that it was mounted higher than the valve covers you won't have any problem and a PCV is unnecessary as it's being vented to atmosphere. Also you wouldn't have to worry about baffles either. You can even put a vented filter directly on the valve cover but those tend to allow a slight oil mist over the valve cover and engine. As far as the PCV valve I think it's purpose is to prevent ignition of vapors in the top end in the event of a backfire.

Bamm · 03-10-2005, 05:08 PM

Okay, side question. What would happen if I just vent one side? Is that sufficient or do both sides need to be ventilated?

*wolfthing2000* · 03-10-2005, 05:45 PM

The 350 in my 69 has valve cover from old school withn the CHEVROLET scroll on it ( closed ) on the drivers side and a breather oil fill on the front of a later model with a pvc port at the rear and a tube to the aircleaner with pcv in line on the passengers side. It seems kinda wrong to me since the draw and vent are all on one side. I think oil fill on one side ( vented cap) and the pcv port and hose to intake manifold on the opposite side would draw air across and through the engine better. But maybe this isn't even necessary. Perhaps the set up the PO put on this engine is fine.
I am rebuilding another 350 or 400 to put back in the truck and I have a set of the old stock closed covers that I realy wish to run, but still trying to figure out how
Dave

franko72 · 03-10-2005, 09:20 PM

I have heard that crankcase ventilation will add life to the crank bearings and rod bearings.Without it the crank spins and splashes the oil and can form small bubbles of air in the oil not letting the oil adhere as well to the moving parts causing premature wear on the crank.

03-09-2005, 07:00 PM	#1
Bamm Cowboy Fan for Life!!!!!! Join Date: Apr 2002 Location: Amelia, Virginia Posts: 2,921	Valve cover / pcv question I am looking at this set of valve covers and I have a question. Is there anything wrong with venting the pcv/breather out the back of the valve cover? Where would you run it to? Underside of the air cleaner base? Thanks guys..... Attached Images __________________ 1967 ShortBed Fleetside 3/4 Drop 350/700R4 Tilt wheel 18 x 8 Torque Thrust II's Future mods: All new gauges & wood bed My Zip is 23002 I ship UPS, USPS

03-09-2005, 07:03 PM	#2
Bamm Cowboy Fan for Life!!!!!! Join Date: Apr 2002 Location: Amelia, Virginia Posts: 2,921	Sorry, here's the other pictures. Attached Images __________________ 1967 ShortBed Fleetside 3/4 Drop 350/700R4 Tilt wheel 18 x 8 Torque Thrust II's Future mods: All new gauges & wood bed My Zip is 23002 I ship UPS, USPS

03-09-2005, 07:04 PM	#3
Bamm Cowboy Fan for Life!!!!!! Join Date: Apr 2002 Location: Amelia, Virginia Posts: 2,921	One more..... Attached Images __________________ 1967 ShortBed Fleetside 3/4 Drop 350/700R4 Tilt wheel 18 x 8 Torque Thrust II's Future mods: All new gauges & wood bed My Zip is 23002 I ship UPS, USPS

03-09-2005, 07:16 PM	#4
cdowns Senior Member Join Date: Jan 2003 Location: daytonabeach Posts: 22,956	you really should have baffeled covers to prevent oil being sucked into the carb __________________ 71c-10 350/2004r/4:11 lowered3/4 longbed/dead by hurricane MEANING OF DEATH::::: SOMEBODY ELSE GETS YOUR STUFF DONT BELIEVE EVERYTHING YOU THINK TAKE MY ADVISE;I DON'T USE IT ANYWAY

03-09-2005, 08:46 PM	#6
VetteVet Msgt USAF Ret Join Date: Jan 2005 Location: Kalamazoo, Michigan Posts: 8,709	Not only that all PVC systems have a check valve in them to prevent gas vapors from getting into the oiling system, and also from overpressurizing the crankcase and blowing seals. I don't think it matters where the vent is if these two criteria are met. I kinda like the clean look it gives. VetteVet __________________ VetteVet metallic green 67 stepside 74 corvette convertible 1965 Harley sportster 1995 Harley wide glide Growing old is hell, but it beats the alternative.

03-09-2005, 09:24 PM	#7
Bamm Cowboy Fan for Life!!!!!! Join Date: Apr 2002 Location: Amelia, Virginia Posts: 2,921	Didn't the mid-80's pontiac V-8's come off the valve covers right into the air cleaner? They just had a "clip-on" filter to keep oil from getting into the carb. Was there anything else in between there i'm missing? Thanks for the responses guys.......Jerry __________________ 1967 ShortBed Fleetside 3/4 Drop 350/700R4 Tilt wheel 18 x 8 Torque Thrust II's Future mods: All new gauges & wood bed My Zip is 23002 I ship UPS, USPS

03-10-2005, 08:22 AM	#9
70short/step Registered User Join Date: Dec 2003 Location: Stockton, CA Posts: 1,579	The best thing to do with that valve cover is to just take out that fitting and plug it. Those covers have a place that you can remove (drill or punch out) in the top of them for the oil fill and PCV valve. That was used for racing purpose and you wouldnt want to use it on a street aplication. I have been watching these and was going to bid on them and do what i said here, but If you are interested in them I will not bid. They are nice covers and would look great on an engine. Happy bidding and hope you get them. __________________ For every person with a spark of genius, There are a hundred with ignition trouble. 70 Short/Step

03-10-2005, 11:03 AM	#10
Bamm Cowboy Fan for Life!!!!!! Join Date: Apr 2002 Location: Amelia, Virginia Posts: 2,921	Is there a site somewhere that would explain the pcv system for me so I can get a handle on what is what? Thanks guys..........Jerry __________________ 1967 ShortBed Fleetside 3/4 Drop 350/700R4 Tilt wheel 18 x 8 Torque Thrust II's Future mods: All new gauges & wood bed My Zip is 23002 I ship UPS, USPS

03-10-2005, 11:21 AM	#12
Putter More Cowbell.... Join Date: Mar 2004 Location: Puckett, MS Posts: 3,569	I saw those on the E-bay yesteday. Looked kinda cool, BUT WHERE DOES THE OIL GET INSTALLED on oil-change day??? I aint pulling the dizzy to do that. __________________ *There once was a member from Puckett.....Who ( fill in the blank blank blank* ) bucket**

03-10-2005, 11:41 AM	#13
Bamm Cowboy Fan for Life!!!!!! Join Date: Apr 2002 Location: Amelia, Virginia Posts: 2,921	Maybe the other valve cover has the oil fill? I can't remember and lost the link. 70 Short/Step - I'm not bidding on them, I just wanted to figure out how he was making that work. Reason being, I have a pair of new-in-the-box billet valve covers that don't have any holes drilled in the top and I kinda like that smooth look and was wondering if there was a way to keep that look and still have everything working as it should. Any idea's will be appreciated........Jerry __________________ 1967 ShortBed Fleetside 3/4 Drop 350/700R4 Tilt wheel 18 x 8 Torque Thrust II's Future mods: All new gauges & wood bed My Zip is 23002 I ship UPS, USPS

03-10-2005, 12:37 PM	#14
70short/step Registered User Join Date: Dec 2003 Location: Stockton, CA Posts: 1,579	Those valve covers that you have in the pics are Performance chevy parts and are worth about $230. Like I said before, you have to punch or drill holes in them for the oil fill and PCV valve. There are bosses in the covers to do this. If you have valve covers that have no holes for oil fill or PCV valve I do not know of any other way to vent the crankcase on a newer post 67 year. Earlier year engines had a tube in the back of the block to vent the crankcase and it just let the oil run out onto the road. The way you put oil in these older engines was the front of the intakes had a tube that stuck up with an oil cap on them. And Putter, I would pull a valve cover (if I had to) instead of the dizzy to add oil! Hope this helps you. __________________ For every person with a spark of genius, There are a hundred with ignition trouble. 70 Short/Step Last edited by 70short/step; 03-10-2005 at 12:42 PM.

03-10-2005, 01:52 PM	#15
68LSS1 Registered User Join Date: Dec 2002 Location: Tampa Posts: 1,191	A PCV valve isn't absolutely needed. You could run a small catch can off the AN fittings on the back of the valve covers. If you ensured that it was mounted higher than the valve covers you won't have any problem and a PCV is unnecessary as it's being vented to atmosphere. Also you wouldn't have to worry about baffles either. You can even put a vented filter directly on the valve cover but those tend to allow a slight oil mist over the valve cover and engine. As far as the PCV valve I think it's purpose is to prevent ignition of vapors in the top end in the event of a backfire. __________________ '68 Short Step LS1/T56, Hydratech, Fatman Fabrications Stage III, Baer, Hot Rods to Hell, US Body, S&W, etc

03-10-2005, 05:08 PM	#16
Bamm Cowboy Fan for Life!!!!!! Join Date: Apr 2002 Location: Amelia, Virginia Posts: 2,921	Okay, side question. What would happen if I just vent one side? Is that sufficient or do both sides need to be ventilated? __________________ 1967 ShortBed Fleetside 3/4 Drop 350/700R4 Tilt wheel 18 x 8 Torque Thrust II's Future mods: All new gauges & wood bed My Zip is 23002 I ship UPS, USPS

03-10-2005, 05:45 PM	#17
wolfthing2000 Account Suspended Join Date: Oct 2004 Posts: 1,276	The 350 in my 69 has valve cover from old school withn the CHEVROLET scroll on it ( closed ) on the drivers side and a breather oil fill on the front of a later model with a pvc port at the rear and a tube to the aircleaner with pcv in line on the passengers side. It seems kinda wrong to me since the draw and vent are all on one side. I think oil fill on one side ( vented cap) and the pcv port and hose to intake manifold on the opposite side would draw air across and through the engine better. But maybe this isn't even necessary. Perhaps the set up the PO put on this engine is fine. I am rebuilding another 350 or 400 to put back in the truck and I have a set of the old stock closed covers that I realy wish to run, but still trying to figure out how Dave

03-10-2005, 09:20 PM	#18
franko72 Franko72 Join Date: May 2004 Location: Cincinnati,Ohio Posts: 471	I have heard that crankcase ventilation will add life to the crank bearings and rod bearings.Without it the crank spins and splashes the oil and can form small bubbles of air in the oil not letting the oil adhere as well to the moving parts causing premature wear on the crank. __________________ 1972 C20 cheyenne Super 402 BB/400 turbo LWB A/C Tilt, Cruise Control, Saddle tanks, Tach My Home Page Better to burn out than it is to rust



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