PCV question

Before everyone jumps on me I have searched the archives and read many post before I decide how to do my PCV on my SBC. I have done the installation and now I have a coupe of questions that I need some advice on. I have a SBC running 3-2's with the old style breather tube up front. I drilled the manifold down through the coil boss into the lifter valley. I then welded a baffle, actually a flat piece of 1/8 alumninum between the triangular webbing to act as a splash shield. I then inserted a threaded nipple and went to a PVC screwed into the center carb. The only breathers i have on the motor is the front breather tube that has a breather on the end not a locking cap. I have checked the PCV for proper flow, it is the old 1965 SBC Rochester 2 barrell screw in type. Here lies the question, it is sucking oil, not terrible, but a little is too much for me. I marked the outside porcelin on a the sparkplugs with a magic marker and they all are a burning beautiful almond except for a small area towards every intake valve which is oil stained. Upon inspection the PCV valve has a little oil in it and the hose has a little oil in it as well. I have used a pint in about 100 miles. Any ideas how to correct this probem. As you know the PCV valve comes out of the center carb somewhat horizontally, they worked ok horizontally in 1965, could the parts man have given my the wrong one? Any ideas or thoughts would be greatly appreciateed.

 

Your baffle isn't baffling enough.
Pretty simple, correction is a different story.
There's a few really current threads about the same thing with the same problematic drilling of manifolds

 

Thanks for the response and I agree. Just looking for a possible solution without tearing welded in baffle out of intake webbing. The air gaps are too small on the baffle up against the webbing to allow any brass scrubbers or such to be pushed in. I suppose I could cut the baffle out and re weld but was hoping someone may have had the same problem and had a solution less than cutting out the wellded baffle. thanks

 

You could try welding 2 more sheet metal baffles over the one you have now.
Study the offy baffles , there's a gravity based maze that the oil can not pass yet air has a basic free path.

You could Google valve cover baffle Images, and get an idea also. But valve cover baffles are in a completely different environment.. you'd need more baffle than those because there is a hell of a lot more oil flying around in the valley

 

Thanks 31 Vicky appreciate your response, wish i could have had a few more responses as I know someone has had the same problem. I see in one of the searches where a guy said he moved his PCV from a horizontal position behind the carb to a vertical position and moved it to where he drilled through the intake and it fixed the problem. Those PCV valves screwed into the bottom of those rochesters 2g's for several years in a horizontal position, i do not think that is my problem , but I may try to put it vertical, would be a easy fix if it happened to work. I welded the baffle between the webbing precisely to avoid this, perhaps i needed to fill the void behind the baffle with material. Is there some type of inline baffle that you are aware of?

 

man, i wish you would have posted some pics. of your set-up. i'm doing the same thing right now! 50's edelbrock #355,3x2, 97's, drilled the back for pcv to center carb plate.i really want this to work with out problems. i'll try to post some pics. tomorrow of my baffle. did you weld yours all the way around? is there some sort of hole on it? please discribe what you did as this seem like it's never fully answered in all the older posts. thanks, kurt.

 

I know man, I read every post i could find on here and decided on doing it this way, now i suck oil. oh well I will get it figured out. I drilled down through the coil boss hole. I made a triangular baffle to fit the underside of the intake manifold between the webbing. I did not take a picture but several guys on here have done the same thing with pictures. I made it fit as tight as i could and spot welded it in every inch or so. I drilled no holes or anything in it only allowing air to pass through the edges. I tapped the hole 1/4 NPT on top with a hose going to PCV valve horizontally out the base of center carb. Fresh air in through old style front breather tube up front. Nice neat clean install. I know someone on here will come forth with an idea for me as many have done it this way. I bought a NAPA valve that the counterman said crossed to a FRam FV100. Some on here said the horizontal valve need a spring in them. Thanks Dick

 

Hey Nick i have the same set up! mine works better tho mine uses a quart of oil every 100 miles!!!
if any of you guys want to add an oil injecter to your engine let me know!!
I think i can fix mine by pulling the intake and useing the old "canister" for the road tube. I made a baffle with some pot scrubber stuff to put in the road draft tube "hole" with a new PCV valve altho i havn't tested it yet. I tell my self I don't have time

 

Make sure that you have a PCV valve that is actually supposed to lay in its side if that is what you are doing. Early Corvette PCV (I think '65 or '66) is what you want.

Next you are still going to have a problem is you are drawing from your lifter valley and using a front mounted breather, all you are venting is your lifter valley and not yoru crank case. It is drawing through the breather on the front of the lifter valley. So once to stop it from sucking oil you still have a crank case ventillation problem that you will need to address.

 

My 67 Impala has a PVC that is horizontal, 327/275 how about a valley pan, GM used on several HP applications over the years? It might help slow the oil down some?

 

Guys, back in 60's (don't know if all had them, but certain about 1963) GMC's with the boat anchor 305's had pcv valves that went inside the valve covers and were screwed into the intake runner on both banks. If you make a splash shield in the valley and another beneath the valves, you can install them into the carb plenum from the bottom. If one isn't enough, use two, but my 283 intake on a 350 worked fine. And orientation of pcv valves makes no difference to function.

 

PNB, first off, I have not been around this stuff as much as you so not as knowledgeable.

On a stock PCV set up, the valve is on the valve cover drawing vapor from the top of the head.The only access to the crankcase would be from oil drain back holes in the head/block and push rod access holes to the valley where there are drain back holes to the crankcase also correct?

So wouldn't the valley have the same access to the crankcase as the heads?

I'm just trying to educate myself here,not arguing.
Warren

 

I appreciate everyones response. I can always plug the hole in the coil boss with a 1/4 npt plug and put a pvc in one valve cover and a breather in the other and pull from side to side. I would have to baffle the inside of the valve covers and cap the oil fill breather in front. It just bugs me when I can't figure something out though and make it work I did not want to drill the valve covers. Therefore I most likely will keep screwing with this setup until I go crazy or I fix it. I'm thinking of brazing a brass tube in the end of the nipple that i have screwed into the coil boss and then drill the tube with several small holes to create a type of jet or baffle and trying that. Has anyone tried anything like this?

 

I built the baffle for my tri power setup under the manifold like you and packed it with course steel wool.
I only have about 1600 miles on it so far but its not using oil so I guess its working ok.
Didn't originally have a baffle at all and the plugs closest to the carb riser were getting oil so I built the baffle and it works.
The pcv valve I have will not work laying down it needs gravity to function properly, found that out the hard way.

 

maybe we should start a list of pcv valves and their working positions and if they worked! some people seem to get through this very easy, but others are still fighting it. maybe some are to picky? probably not. missing oil is not good.

 

I understand, but believe me I am not picky, I just like things right. I most likely should of filled the intake baffle void with the bronze chor-boy but that is water under the bridge now. If i have to rip the intake off and redo the baffle i will, but this has been good discussion none the less. I refuse to believe that the orientation of the valve should make a difference, flow direction is obviously critical, but the orientation should not matter. The pintle should be surrounded by air which should hold it away from any side restrictions and it should operate from any angle. The valve I amusing is a Fram FV100 which is deigned to screw horizontally in the carb base. Someone please correct me if i am wrong in this thinking.

 

The early ones were not spring loaded and used gravity to close the valve. If one of them is laying on its side when you step on it and reduce the vacuum, the pintle simply falls on its side and and does not regulate the air flow. If you shake one and you can hear it rattle then it is a gravity PCV valve and won't work as expected laying down.

 

ok. heres the baffle i'm hoping to use, i havent finished it because i'm still seeing what you guys are doing! am i close? start over? point me.

 

maybe now? please work pics.

 

I'd venture to say that there is 100 times more oil flying around in the valley than in the valve covers.
There is a huge difference in the baffling required for each location.
The blocks that had a PCV valve in the rear of the manifold have a completely different design of that area and a very substantial baffle located in the rear of the block. Its nick name is "soup can" to give you an idea. I assure you drilling a hole in the manifold and using something minimal is not the same.

Using non vented valve covers and custom PVC system is going to require some very innovative problem solving.

Considering the heat and vapors and hot moisture rise, the top of the valve cover is the best place and much different than drawing from the valley.

 

That looks good to me. If I were doing it, I'd fill the cavity under it with copper wool like the inside of a standard breather. Copper pot scrubbers are in most every grocery store.

 

Looks good to me too. That's almost exactly like I did it and it doesn't seem to be sucking oil. I would include the pot scrubber for good measure, if I had to do it over again.

 

PCV?? I thought this was gonna be about PVC .... sorry.

 

i don't know if were talking oil just flying around in there or is it all about suction. i've got a small gap around the edges that could be a problem. does it need to be more of a mouse maze leading up to the hole?

 

I tried all kinds of stuf with my o/t t-bucket,especially modifying the M/T rocker covers...beat my head against the wall until I found this breather/cap.
(Sorry for the weak pic,but you can see it on the far right,along with regular black 3/8 fuel line going to the base of the carb,,no hose clamps were needed)
It twists into the cover with a flat gasket(distributor gasket),its gotta grommet for the 90-deg valve I used,& the inside was filled with regular sponge type foam.
I contacted JAZ products & told them I worked at a Comm College(which I did) & had them send me a small brick of sample foam they use in their fuel cells...Auto Tech Dept "project".
I replaced the original foam in the breather cap with the fuel cell stuff & screwed it on.
No more oil going into the intake stream,,yay.I kept verifying my attempts on baffeling the covers by using some clear plastic test-hose from homeless depot.
Once I used the new setup,the hose stayed dry as a bone,& trust me I leaned on this bitch hard for about 15 minutes..standing up & looking at the hose at intersections,etc.
The other cover has a regular push in K&N breather filter.

Smart & Final has the Stainless & Copper scrubbers,,,I gotta bag of SS ones for the alum boat I'm restoring & they dont come apart,,I imagine copper would work too & it's more traditional than stainless!

 

427 Ford dual quad FE PCV valve location. There is a breather element that goes under the plate to reduce oil consumption.



You can see where I ran my PCV valve to the Ford road draft tube location in the back of the intake on the early 352s. Mine is the one pictured above that screws into the Rochester carb base. I packed the road draft tube with a copper pot scrubber and added a screw through the side to keep it from migrating.

 

Go-Twitchy that is exactly the baffle i made except for the 90 degree center boss you have. I did not drill the holes either. Exact baffle only welded in, without any filler in the void. I drilled through the coil boss that is very close to where you drilled.

 

Tommy, isn't the FRAM FV100 the same as the PCV valve you have pictured with the pintle surrounded by a spring? Or are you saying that some of the valves that screw in may not have this pintle spring? I am a little confused as to what valve I actually need. Went to the auto store and said I needed a screw in PCV valve for a 1965 327. I checked the flow and screwed it in, perhaps I have the wrong valve. The counterman crossed the FRAM FV100 number to a NAPA number.

 

This is what you need to replace , the "Soup Can" in the valley.

 

that fine if it's a early block, mine's a 79-85 sbc. no road draft tube, no threads for the can. what makes the soup can work so well? could the design be adapted or down sized to fit around a small hole of say 3/8"? i've never seen one up close to understand how it isolates the hole so well.