MikeStang 247 Report post Posted January 22, 2019 I have not been running a PCV valve on my 408 and have always had oil leakage problems out of the small breathers on the valve covers. So in an effort to stop this I have decided to give a PCV valve a shot. Motor was built and has been on the dyno and a few years later I had if freshened up so there is no significant blow by, and the valve covers are baffled on all 4 holes. If I recall correctly the layout for a working PCV system should be as follows. My valve covers have 2 Holes per cover for a total of 4 Holes. 1. PCV valve in Passenger side REAR valve cover hole 2. Breather filter on Driver valve cover in front hole 3. Plug the remaining holes in Driver and Pass covers that are not being used. This sound about right? Also What is a good PCV valve Part number to use that can be purchased locally at O-Reilly or Auto Zone that would be a good fit for this motor? Quote Share this post Link to post Share on other sites
1969_Mach1 333 Report post Posted January 22, 2019 Yeah, that's the correct setup for a PCV system. I can't give you a part number for a good PCV valve to use. I might be wrong, but I was taught they vary a little depending on engine size. I ended up with one for a Chevrolet only because it has a short 90 degree elbow on top of it so it easily clears the export brace. If you don't want a PCV spec'd for a Chevrolet you can remove the elbow and put it on another PCV valve if needed. Quote Share this post Link to post Share on other sites
Alan_Mac 48 Report post Posted January 22, 2019 It would also help if the drivers side breather was connected to the air cleaner base. I use and adjustable PCV and it fixed my problem. 1 RPM reacted to this Quote Share this post Link to post Share on other sites
MikeStang 247 Report post Posted January 22, 2019 1 hour ago, Alan_Mac said: It would also help if the drivers side breather was connected to the air cleaner base. I use and adjustable PCV and it fixed my problem. You happen to have a part number or manufacturer for that PCV valve you used? Quote Share this post Link to post Share on other sites
MikeStang 247 Report post Posted January 22, 2019 What difference does it make if the PCV goes to the air cleaner or to the carb really? Altho I do have my brake booster plumbed into the big fitting on the rear of carb and I was always told you should not T into the booster line for the PCV valve, but where else do you hook it besides the air cleaner...I think my air cleaner base has a provision for it but I'm sure I dont have the little fitting for it any longer. How does it even get any positive vac if hooked to the air cleaner tho...that's not a sealed enclosure? Quote Share this post Link to post Share on other sites
LoneWolf2U 136 Report post Posted January 22, 2019 Standard motor valve V156 Hook your power booster line directly to your intake for best vac source. the pvc line to the base of the carb. Positive vac. never hook the pvc line with the booster line, a possible oil contamination may occur. Quote Share this post Link to post Share on other sites
aslanefe 333 Report post Posted January 23, 2019 7 hours ago, Mach1Rider said: never hook the pvc line with the booster line, a possible oil contamination may occur. What is going the get contaminated with oil, brake booster? If so, it doesn't make sense to me. There is vacuum pulled from both the booster and PCV, so oil can't flow from PCV to booster; Oil has to flow from PCV to intake or carb (which sends it to intake) as intake is creating the vacuum and pulling the oil, not the brake booster. Am I missing something? Quote Share this post Link to post Share on other sites
aslanefe 333 Report post Posted January 23, 2019 8 hours ago, MikeStang said: What difference does it make if the PCV goes to the air cleaner or to the carb really? Altho I do have my brake booster plumbed into the big fitting on the rear of carb and I was always told you should not T into the booster line for the PCV valve, but where else do you hook it besides the air cleaner...I think my air cleaner base has a provision for it but I'm sure I dont have the little fitting for it any longer. How does it even get any positive vac if hooked to the air cleaner tho...that's not a sealed enclosure? I would hook up the power booster to intake and PCV to carb or air cleaner. If you hook up the PCV to intake, the cylinders close to the port will suck oil vapors and change combustion on only those few cylinders. If you hook PCV to carb or air cleaner, each cylinder will get a fair share of oil vapor. Original air cleaner may not be air tight but there is vacuum as air is pulled in. On my car with original air cleaner, I can feel the vacuum if I try to lift the cover up when engine is running, it takes more force to lift the cover compared to engine not running. If you have the original cleaner, try plugging the snorkel with a rag, the engine should die. Quote Share this post Link to post Share on other sites
aslanefe 333 Report post Posted January 23, 2019 Forgot to mention, as far as I know carb pulls vacuum on the crankcase through PCV valve, but there has to be air entering to crankcase somewhere. Otherwise air flow through the crankcase will stop. So the breather/filter goes to air cleaner base in order to supply the required (clean) air to crankcase. Quote Share this post Link to post Share on other sites
Alan_Mac 48 Report post Posted January 23, 2019 19 hours ago, MikeStang said: You happen to have a part number or manufacturer for that PCV valve you used? http://mewagner.com/?p=444 no big deal setting it up. Not cheap but it works great. Quote Share this post Link to post Share on other sites
Alan_Mac 48 Report post Posted January 23, 2019 19 hours ago, MikeStang said: What difference does it make if the PCV goes to the air cleaner or to the carb really? Altho I do have my brake booster plumbed into the big fitting on the rear of carb and I was always told you should not T into the booster line for the PCV valve, but where else do you hook it besides the air cleaner...I think my air cleaner base has a provision for it but I'm sure I dont have the little fitting for it any longer. How does it even get any positive vac if hooked to the air cleaner tho...that's not a sealed enclosure? http://mewagner.com/wp-content/uploads/2016/01/Hemmings-Muscle-Machine-Jan-2016-p64-67.pdf Also the tech articles at M/E Wagner are a good read. Quote Share this post Link to post Share on other sites
1969_Mach1 333 Report post Posted January 23, 2019 12 hours ago, aslanefe said: What is going the get contaminated with oil, brake booster? If so, it doesn't make sense to me. There is vacuum pulled from both the booster and PCV, so oil can't flow from PCV to booster; Oil has to flow from PCV to intake or carb (which sends it to intake) as intake is creating the vacuum and pulling the oil, not the brake booster. Am I missing something? I've heard don't connect the PCV and brake booster vacuum line to the same port ( or tee them together as well. I don't understand it either. For me, when using an aftermarket dual plane intake I don't like using the provided vacuum port on them because it pulls only from cylinder #4. In my opinion, they put that port in a bad location. The vacuum port at the carb base or spacer (if you have one) pulls from the entire motor. Quote Share this post Link to post Share on other sites
Vicfreg 771 Report post Posted January 24, 2019 If your engine doesn't make a lot of vacuum, and you jam on the brakes, especially with the engine loading up due to a downshift, the PCV outflow will follow the path of least resistance, which could be to the brake booster. My PCV runs to the base of the Carb/EFI, and the brake booster has a dedicated location at the very rear of the intake manifold. Also, don't use fuel line, use vacuum hose. I have attached a typical 1970's Ford diagram for the PCV routing, which goes to the base of the Carb. On your Holley or aftermarket carb, it may be in the back or on the side. Quote Share this post Link to post Share on other sites
aslanefe 333 Report post Posted January 24, 2019 There is a check valve at the booster which will not let flow into booster and always keeps the booster under vacuum. If you have flow/oiil vapor going into booster, you will not have power brakes. Quote Share this post Link to post Share on other sites
MikeStang 247 Report post Posted January 24, 2019 Well got it all done this evening. The Vic Jr. Intake does not have any vac port holes on it lol so I did as Holley suggests and connected the booster to the back 3/8 port on the carb and the pcv valve to the 3/8 port on the front bottom of the carb. Hooked up Vac gage to small port on carb base and tuned carb...Not so sure how accurate the small port on the base of the carb is. Best Vac reading I could get was about 8.9" Which seems really low to me because I could have sworn it was around 12" late time I checked it but brakes seem to feel the same.. Motor actually seemed to run better actually just sitting idling in the shop. Quote Share this post Link to post Share on other sites
aslanefe 333 Report post Posted January 24, 2019 1 hour ago, MikeStang said: Well got it all done this evening. The Vic Jr. Intake does not have any vac port holes on it lol so I did as Holley suggests and connected the booster to the back 3/8 port on the carb and the pcv valve to the 3/8 port on the front bottom of the carb. Hooked up Vac gage to small port on carb base and tuned carb...Not so sure how accurate the small port on the base of the carb is. Best Vac reading I could get was about 8.9" Which seems really low to me because I could have sworn it was around 12" late time I checked it but brakes seem to feel the same.. Motor actually seemed to run better actually just sitting idling in the shop. What are your vacuum readings on the ports you hooked up the PCV and booster? Quote Share this post Link to post Share on other sites
stangman69 17 Report post Posted January 24, 2019 (edited) Wouldn't you want to pipe it from valve cover to PCV valve to air / oil separator to intake vacuum? That Wagner adjustable PCV valve looks like a slick little gizmo. Anybody ever use one? I was planning to duplicate the factory Fox Mustang setup except add in an adjustable PCV valve and an oil / air separator to keep the intake and incoming air as clean as possible. Edited January 24, 2019 by stangman69 Added clarifying comment Quote Share this post Link to post Share on other sites
MikeStang 247 Report post Posted January 24, 2019 11 minutes ago, stangman69 said: Wouldn't you want to pipe it from valve cover to PCV valve to air / oil separator to intake vacuum? That Wagner adjustable PCV valve looks like a slick little gizmo. Anybody ever use one? Well My valve covers are baffled on all 4 Holes, so I'm hoping that the Valve wont suck any oil up and pump it into the intake LOL...The factory didn't need a separator so hopefully I wont...I guess when I take it out for a ride and put my right foot to the floor if I make a smoke screen I will know I gotta have a separator or catch can LOL. Alan Marc has used one of the Wagner valves it seems. 1 stangman69 reacted to this Quote Share this post Link to post Share on other sites
MikeStang 247 Report post Posted January 24, 2019 10 hours ago, aslanefe said: What are your vacuum readings on the ports you hooked up the PCV and booster? I did not check those, but I will tonight. the last time I remember checking them I thought I had around 12". When I built my motor I had Comp Spec out a cam and told them I wanted a cam that would make 500hp with my AFR heads etc.. They sent me the grind info and it looked good in terms of lift and duration but would be ground on a 106LSA and I KNEW this would cause me Vacuum issues with my power brakes so I told them to change the LSA to 112 and send it... They did and my idle for the size of the cam is nice and refined and smooth and my power assisted brakes will toss your ass through the windshield with pinkey toe effort LOL... Oh and it made 550hp despite them telling me that it wouldn't even make 500 if I changed the LSA to what I wanted. Hindsight tho If I had to regrind it I would probably go to a 110 LSA because I want a little more Chop Chop at idle now haha... Just so long as my power brakes work well I am happy tho. Quote Share this post Link to post Share on other sites
Alan_Mac 48 Report post Posted January 24, 2019 I have the adjustable PCV value as shown in this picture. I was always popping my breather caps with high RPM bursts until I added the adjustable PCV valve plumbed the breather to my ram air base. Quote Share this post Link to post Share on other sites
RPM 1,190 Report post Posted January 25, 2019 1 hour ago, Alan_Mac said: I have the adjustable PCV value as shown in this picture. Alan do you have a make and model on the adjustable valve? Quote Share this post Link to post Share on other sites
Alan_Mac 48 Report post Posted January 25, 2019 http://mewagner.com DF-17 Dual Flow PCV Valve #1 Quote Share this post Link to post Share on other sites
MikeStang 247 Report post Posted January 25, 2019 I wonder if plumbing the Valve to the bottom of an open Element air cleaner would produce enough of a Vacuum to make the valve work correctly? I can see how a semi closed element air cleaner assembly would produce a bit of Vac but just don't know about a full open element unit. Quote Share this post Link to post Share on other sites
1969_Mach1 333 Report post Posted January 25, 2019 18 hours ago, Alan_Mac said: I have the adjustable PCV value as shown in this picture. I was always popping my breather caps with high RPM bursts until I added the adjustable PCV valve plumbed the breather to my ram air base. At high engine RPM the PCV will not flow much so crankcase vapors also get pushed out through the breather. That is normal operation on all cars since the advent of a PCV valve. That is why crankcase breather filters use to get replaced as a normal tune-up item. I have a pair of Scott Drake valve covers with a oil filler tube like shown in your picture. They are ready for the garbage can. They don't hold the filler cap on very well compared to twist on and the other type that push into a grommet. Connecting the breather cap to an air cleaner will only force crankcase vapors into the air cleaner at high RPM. Then back into the motor instead of simply into the atmosphere. It won't have any effect on how well the vented oil filler cap operates. If you originally had that other vented oil filler cap Scott Drake offers, take a close look at it, the vent holes are tiny and probably will not flow enough air for motors like yours. Quote Share this post Link to post Share on other sites
aslanefe 333 Report post Posted January 25, 2019 2 hours ago, MikeStang said: I wonder if plumbing the Valve to the bottom of an open Element air cleaner would produce enough of a Vacuum to make the valve work correctly? I can see how a semi closed element air cleaner assembly would produce a bit of Vac but just don't know about a full open element unit. Do you have an open element air cleaner with the inlet on the bottom? If yes, just hook up your vacuum gauge there and see how much vacuum it pulls. Quote Share this post Link to post Share on other sites
