With the prospect of driving my daughter in several parades this summer, I decided that this was the year to add a PCV system to the 235 in the '51. I'm usually one to figure things like this out on my own, and this case was no different. I did some research and found a couple of different procedures to add the PCV, but I wasn't really happy with some aspects. I also had some good advice from someone whose opinion I respect (thanks Nate!!!). I wanted to find something that didn't require much investment, or any special parts or tools. This is what I came up with. I started out at my FLAPS. I picked up a PCV valve. I didn't pay attention to which one. As far as I can discern, there isn't much difference in them except the mounting hole size or hose size. I also picked up an oil filler cap for an early '70's F*** truck (Murray p/n 8071). This cap is non-vented, contains gauze filter material inside and has a mounting hole in the top for the PCV valve. I also picked up a length of hose and a fitting to connect to the vacuum port on the intake manifold. I won't bore you with installation instructions for that. I think you all can figure that out. For the fresh air intake, I decided to use the road draft tube. Well, part of the road draft tube, anyway. One of my parts engines had the tube removed from the breather. I used this one, because I was concerned that highway driving would leave the draft tube and PCV competing, and the engine loosing all ventilation. After a couple of weeks of soaking in gasoline to loosen and remove all of the built up sludge, I painted the tube. Next, I installed some gauze type filter media that I found at the FLAPS (Micro-Gard p/n 42998BP). I wanted to do this because, even though the tube was baffled, I didn't feel the baffeling would provide adequate filtration to the incoming air. This gauze filter is the same type that was used in PCV filters on older carbureted vehicles. I think that the end result will give a good air flow through the engine without too many modifications. I'm open to comments, but please be kind...
Pcv Looking very nice there ! . yes , the PCV Valves are calibrated differently for different engines , you could have looked up for a '79 Chevy 230 CID L6 but I'm sure it'll be fine . If you suddenly begin to use more oil , replace that valve with the 230/250/292 one . Remember : when you're blowing & going down The Open Road , the PCV Valve closes and does nothing ~ the engine will vent via the road draft tube so don't panic when you see oil dribbling out that filter gauze . You could have easily cleaned the old Road Draft Tube by heating it up in your BBQ ~ after a while of heating , the old oil sludge begins to burn and will smoke terribly and stink a lot , let it go and when it's done and cooled off , you can tap & shake out the resulting crud . I found one of my old original inverted Road Draft Tube PCV Valve holders , OEM GM product , I've forgotten who wanted it....
PCV valve ? Hey guys Could one of you gentleman tell me the excact purpose/function of the valve ? Thanks Martinius.
Nate- 'Twas me. What do you think. Which do you think is better. If you think the OEM is better, I'll still take it... Martinius- The PCV valve replaces the function of the road draft tube as a means of providing positive air pressure in the crankcase. It also evacuates all of the vapors inside.
I am always learning, so if my vented valve cover, Oil filler tube with clean filter/cap/chrome!!....and I have a road draft tube operable....why do I need a PCV that works only at low RPM?? I would have put the PCV through the valve cover behind the Carb...for cosmetics. But..I don't know squat so if its helps my motor in any way I'm game. I want my 1942, 216 to last forever!
Flashlight- My main concern is about idling. I live practically in town, so my daily commute never allows me over 35. Also, I am planning several parades this year. In these cases, the road draft tube does not work. If you mainly drive over 35 mph, then the draft tube will do you just fine.
Advice needed PCV Valve combined with road draft tube ? I have been looking for pictures of 61-67 Chevy & GMC 6cyl engines with a PCV valve installed but have`nt been able to find any yet ! Maybe some of you guys can help me out here and find me some pics ! But i do have found a Fram PCV valve on EBAY made to fit the 235 6 cyl engines. The rubber grommet part and the particular valve cover cap with the hole in it i have`nt found but i am still looking fore that to. Would it be adviceble to have both the PCV valve and the road draft tube? Thanks martinius
PCV Funtion It draws out the by pass combustion fumes and burns them , this helps keep the inside of the engine clean and makes it last longer because the fumes are corrosive in nature . It also reduces pollution sharply at NO negative cost whilst simultaniously reducing oil leaks & weeps . If you love your engine (any engine) , it should have a PCV Valve fitted . Best way is to connect the fresh air intake through the air cleaner , after the filtration part so no matter which way it's working , it keeps the inside of our engine clean , NO DUST .
The plot thickens, what fresh air intake? I only see where Tim plugged in the valve, and brought it to vacuum..nice fittings on the manifold, by the way. Isn't there enough fresh air intake through the vented valve cover and road draft tube? I do remember cleaning the accumulated crud from my 216, so if this will alleviate some sludge build-up...that's a plus.
Good question Flashlight! Its this combination i am thinking of aswell. I need a grommet and a valve cover cap with the hole in it. Martinius.
Flashlight- The valve cover is the non-vented variety. All fresh air is coming in through the old draft tube. That's why I inserted the gauze filter, so it can filter the incoming air. Nate- My Fram air filter does have the provision for the fresh air. I never came up with what I thought was a suitable way to plumb it. And, if I ever get the dual carb manifold up and running, the new air filters don't have it.
All PCV systems I'm familiar with provide crankcase ventilation under all engine operarting conditions except a backfire. The valve has a calibrated spring which controls how far the valve is opened or closed depending on engine vacuum. At light throttle settings, ie high manifold vacuum the valve closes down against the spring to restrict flow. At high engine loads, ie low manifold vacuum the spring opens the valve allowing more flow through the valve. In the case of an intake backfire the valve will backseat preventing the backfire from igniting the crankcase vapors and damaging things like crankcase seals, valve cover gaskets, or at the very least blowing off the oil filler cap. PCV systems reduce crankcase vapors caused by blowby, and also reduce moisture in the crankcase. Probably the single best thing you can do for your engine, your oil, and the environment. If I remember the numbers correctly, PCV systems reduced total vehicle hydrocarbon emissions by 40% compared to a draft tube system. John
Valve cover cap and PCV valve combo for the 6 cyl engines? Hey guys This is an intresting issue to get more information about. I wonder if the valve cover cap and PCV valve are for sale as a combo for the 216/230/235/265/296 6 cyl engines ? I have seen chevy engines with breathed air caps with a hose connector that have the PCV valve installed in it as a combo. Anyone know how they look like and where to buy these?
Oil Caps Therin lies the rub ~ These caps with a hose barb or grommet for the PCV Valve proper , used to be very common things but now , you have to find an old Automotive Cap " Buyers Guide " ~ this is a paper book that has pictures of every cap they make ~ I no longer have my old catalogs are the well meaning but dim witted retard on night shift " cleaned up " when I was off duty and no one ever saw my books again . Happy hunting ! I know what you need is out there ~ I cobbled up a sealed breather system on my 1959 Nash Metropolitan FHC's 1500 engine , no PCV valve, it's just plumbed from both the rockerbox and the tappet chamber , up to the fresh air nipple on the air cleaner , it works fine , not much vacuum except under full RPM's but since I used my ' 60 second breakin ' , this engine doesn't burn a drop of oil and has almost zero blowby . I just wanted a closed vent for that pesky water vapor that's always inside every engine @ cold startup .
Martinius- You probably won't be able to find a combo, you will probably have to buy all of the parts a la carte. As far as the parts for the later model 6's with a OEM PCV system...I can't for the life of me remember what they all look like. I had a '70 with a 250, but it has been long enough ago that I have since forgotten. The parts I was finding for them were not quite what I was after. The part numbers I included in the original post were for the brand that O'Reilly Auto Parts carries. I don't have a part number for the PCV valve. I picked it up at a different time and didn't think about saving the package. Basically, the exact parts won't matter. As long as you have vacuum to the PCV valve and a fresh air intake, it will work properly. There are minor differences in PCV valve, but I don't think they are enough to cause a problem. Find out what is available locally and go from there.
Now...I'm so confused. Nate was talking, using filtered fresh air intake. Not really sure how I would plumb that to my Air Filter.
Found this while searching for something else tonight. https://talk.classicparts.com/showthread.php?t=5370&highlight=positive Ken
Flashlight- You don't have to run the air intake to your air filter. Just as long as the air that is coming into the crankcase is filtered in some way. That is the purpose of the gauze filter media that I installed in the old crankcase breather. Ken- That is a good thread...one I never found when I was doing my research.
Combo chevy PCV valve and breather cap. Hey guys . I found one on EBAY.But this guy does`nt ship to Norway anyone could help out here ? http://www.ebay.com/itm/380426308352?_trksid=p5197.c0.m619
