i'm sure he'll be back soon, only been a day. and this thread's staying remarkably on topic
excessive 340 crankcase pressure
- Thread starter skidshoe93
- Start date
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skidshoe93
Active Member
yellow rose
Overnight Sensation
Where are you pulling fresh air into the engine with that set up? Adding another valve does nothing. You need a breather on one side, the PCV valve on the other and let it pull fresh air into the engine and out through the PCV valve. That's how it's designed to work.
If you are trying to use the PCV system to pull a vacuum in the crankcase, you can do that. Two valves won't help. It also won't work if you have excessive blow by. I'm all for getting a depression in the crank case. But you aren't doing that either.
Did you ever do a leak down test? If so, post up what you found. If not, you need to.
skidshoe93
Active Member
hey just wanna say thanks to all you A body folks for the response to my issue sorry I'm late on getting back works kicken my butt. I've up loaded some new photos I hope will help anyway let me clarify a few things mtr has just over 5k on a total rebuild new keith black pistons all the Eddy stuff was new outa box compression good (150) plugs look good car runs great & only does the blow by under hi rpm.If you look at new cars some have an O ring around dip stick & I have even seen some with a lock I've got some good ideas from here & will try & apply them & will keep my progress updated.
skidshoe93
Active Member
Donnie514
Well-Known Member
I am saying the PCV valve can not be mounted on the top of a breather. Looks like the bottom of them two breathers is open to the atmosphere.The PCV must be sealed at the mounting in the valve cover with a rubber grommet and the breather must be in a different location on a valve cover and/or on the other valve cover. PCV sucks air out of the motor and the breathers let air in or out as the crankcase pressure requires.
skidshoe93
Active Member
yellow rose thanks for the response & yes on needing another breather to pull in air I've been talking to some folks about that I need to pull a vc & cut out the blank if I do that can I still run the set up I have? Thanks
skidshoe93
Active Member
skidshoe93
Active Member
hey Donnie no the 2 breathers are closed I've gotten some good info from here I just have to figure what's gunna work this has been a fun project for the car is original on out side but an 018 underneath I'll try & keep updates going Thanks
skidshoe93
Active Member
Donnie514
Well-Known Member
In reference to the dip stick I just went to my garage and checked out my motors.
Original 340 dip stick has no seal and sits inside the dip stick tube. On the Race motor I installed the Mopar chrome dip stick from Summit. Part # P4349628
Now this on has a real nice seal at the top. Fits snug and seals nice.
Original 340 dip stick has no seal and sits inside the dip stick tube. On the Race motor I installed the Mopar chrome dip stick from Summit. Part # P4349628
Now this on has a real nice seal at the top. Fits snug and seals nice.
skidshoe93
Active Member
yes on fresh rebuild
yes on fresh rebuild 5k on mtr it doesn't use oil out tailpipe just the mist from dipstick I've gotten some good feed back from here I'll keep posted what I implement & how it goes Thanks
yes on fresh rebuild 5k on mtr it doesn't use oil out tailpipe just the mist from dipstick I've gotten some good feed back from here I'll keep posted what I implement & how it goes Thanks
skidshoe93
Active Member
skidshoe93
Active Member
ah cool! I'll check that out thank you!!
skidshoe93
Active Member
Donnie514
Well-Known Member
If them two … breathers... are sealed then they are not "BREATHERS" You need to add one regular breather and I would put one on each side.
skidshoe93
Active Member
thanks car original on out side I bought it in 1980 $750 but have done many things since those days was parked for 20yrs (kids etc) spent much time & $$ making this the last rebuild I'm getting some good feed back from here thanks
skidshoe93
Active Member
skidshoe93
Active Member
if I do that & run open vc caps can I still vent to catch can & will the breathers puke oil?
Donnie514
Well-Known Member
I have never ran a "catch can" and see NO reason for you to run one. NO, NO, your motor will NOT puke oil. I wouldn't let you mess up that damn good looking car.
I have ran a vac u pan system to my headers in the old days but not on anything driven on the street so forget that idea.
One PCV valve to the manifold vacuum, and TWO regular breathers. That way you only need to drill one valve cover.
I have ran a vac u pan system to my headers in the old days but not on anything driven on the street so forget that idea.
One PCV valve to the manifold vacuum, and TWO regular breathers. That way you only need to drill one valve cover.
DesertRat
Leading edge boomer
Following this because I have been through it. Picture the engine sealed to atmosphere. Then picture adding a filtered fresh air inlet on the left valve cover. Then Picture adding a device that enables you to pull a vacuum on the engine crankcase (PCV valve) on the right valve cover. Then picture plumbing the PVC valve into the vacuum port at the base at the front of the carburetor designed for the purpose. In order to work correctly the engine has to be able to breathe and you must be able to pull a vacuum on the crankcase. Without that you will have uncontrollable emissions coming from every open to atmosphere place on the engine regardless of ring condition or otherwise. Under hard acceleration all engines pressurize the crankcase. (specially built race engines excepted "yellow rose")
Here is a complete PCV system as it's designed and supposed to be used. Leave one element off and it's not complete. The PCV valve installs directly into the valve cover, not in the top of a valve cover breather. Some Fords actually did install the PCV valve into breathers, but those breathers were closed to the atmosphere on the bottom, so the vacuum from the valve was sealed to the engine, as it is supposed to be. Look at the picture. Study the picture. Duplicate the picture on your engine and then your PCV system will be correct. At that point, you can start accurate diagnosis. Once the PCV system is repaired and installed in its entirety, that may just solve the problem, but you'll never know if you keep doing things like adding a second PCV valve which does nothing to help your problem. Look at the picture. Study the picture. Duplicate the picture.
Donnie514
Well-Known Member
Hey Rusty rat rod, I like the diagram you posted.
Don't like that fancy rubber hose going to the air cleaner, well just because I am old.
How bout a diagram with the old down draft tube? The new green people would ****.
The tube that bolted on top of the lifter gallery on the rear of the motor and vented down below the motor cut off at a angle so as it could such air out of the crankcase.
I think Ford was good for that.
Don't like that fancy rubber hose going to the air cleaner, well just because I am old.
How bout a diagram with the old down draft tube? The new green people would ****.
The tube that bolted on top of the lifter gallery on the rear of the motor and vented down below the motor cut off at a angle so as it could such air out of the crankcase.
I think Ford was good for that.
I know, right? My 331 Hemi had a road draft tube on it. Just comes right out of the crankcase and runs straight down into the air stream under the car and dumps right out into the atmosphere. lol I'll defend the PCV system though, as a bit more than emissions. It actually helps the rings seal with the vacuum it puts on the crankcase. Course, in really hot street and race applications where the engine doesn't produce a lot of vacuum it really doesn't do a lot of good. That's where the evacuation system through the header collectors comes in. But the PCV system WORKS for most street cars and should be used, IMO.
jeffnmo
Just another Mopar Maniac
RRR,s diagram said it all, but here is my 340 set up just like the factory did it. You can have just a breather too, it dosen't have to be plumed to the air cleaner.
Jeff
Jeff
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