Hi All I need some advice on this engine its a 400 bored over 60 I always had blow by or back pressure since rebuilt I but Atomic EFI on it and notice I was getting a lite coating of oil on the throttle body,no pcv 1 valve cover goes to air cleaner ,other has a vented cap, Well I took of the one going to the air filter blocked it at air cleaner ,then I put one on with no vent hole. I didn't notice it before, But I took it for a ride and it blew the other valve cover breather off, so I changed breathers one in each valve cover and a oil vent cap, seams alright but I was thinking of adding a pcv to exhaust pipe or a catch can what do you guys think Thanks
Steve

 

Do you have a PCV to manifold vacuum?

 

Yes but last time it was hooked up it sucked the oil out

 

You need valve covers with baffles. Without a PCV hooked to vacuum you will blow oil out the fill tube and dipstick tube. I supplemented the PCV with hose running from the valve cover breather to the air cleaner for some extra vacuum on my old 330.

 

Eric, I have baffle in the valve covers,and I tried the air cleaner thing ,Not sure what to do
Steve

 

Perhaps modifying your valve covers with different baffles or get a breather that will accept a PCV.


Use this to your aircleaner:





Something like this for your PCV

 

Eric ,I had that set up. To the air filter but it was leaving a oil film on my new EFI system I don't want gum it up?
Steve
I have roller rockers on this so I have tall covers w/baffle in them

 

With excessive blow-by that is forcing crankcase gases and oil mist out wherever it can, this seems like one of the short list of options. It's probably smelly with so much blow-by, though. If you can connect a PCV in the system somewhere, that should draw the blow-by into the intake to be burned. The W engines had a PCV port on the intake manifold and a vent in each valve cover - that setup may be an option for you, but you may need a baffle inside the intake where the PCV port goes through.

 

There seems to be an elephant in the room.
Maybe your rings aren't sealing properly, or one was broken when you installed the pistons.
Have you given it a compression test?. If the readings are low, or one cylinder is significantly lower than the others it may be news you don't want to hear.....


Roger.