I have a 351w in my boat with the following modifications. I am having a pcv valve that is fluttering, and a little oil coming out of the dip stick. Pcv valve is to port on intake and the drivers head has a vent back to the air cleaner.

351w
Holley 4160
Wiland stealth
E-street heads
Harland Sharp roller rockers
Lunati
Advertised Duration (Int/Exh): 280/290
Duration @ .050 (Int/Exh): 214/224
Gross Valve Lift (Int/Exh): .472/.496
LSA/ICL: 112/107

 

Mine was rattling around for a long time, I thought thats what is was supposed to do.
I have read that its supposed to rattle, then ive read that its not.
I just did mine yesterday and the new one does not make a sound.

Just a tip, When you change out the grommet for the PCV valve, Do not use a Dorman brand, I used one an in only a few years it got hard as a rock, leaking oil and was crumbling to peices,(typical aftermarket garbage) I almost dropped the bottom part of it into valve cover, luckily I was able to hold it with my finger and use needle nose pliers to get it out from inside the valve cover.

 

Go to your parts store and look at all of the PVC valves. After having many problems getting my oil pressure to drop. I finally just bought a few different types and tried them out. The one that I ended up using has no internal valve, just a small hole in the bottom that allows enough air through that it's doesn't cause tuning issues. You can enlarge the hole by drilling if necessary but if you go to large it will cause a high idle. I think I ended up with 1/8" hole. My oil pressure is right in the middle where it should be now.

 

How does a PCV valve affect your oil pressure? The PCV vents the crank case, which should be no more than any pressure from combustion blow-by, into the intake manifold, which should never get above atmospheric unless you have forced induction. An oil pressure gauge should measure the pressurized oil coming out of the oil pump, which should be limited by its internal bypass spring. The two should be in separate pressure regions.

 

If it has nothing to do with oil pressure then why would a faulty pcv cause oil to seep out of places that it shouldn't. I'm just telling what solved my problem with oil seepage that was directly related to higher readings on the oil pressure guage on my truck. If a crankcase cannot ventilate properly then pressure builds within the motor. This causes oil to leak out of the places with least resistance which is usually at the top of the motor. I.e. Fill cap, vent, pcv grommet, or dipstick.

 

What you say is correct; too much pressure in the CRANKCASE causes oil to leak out of areas exposed to that pressure, such as the front or rear main seals, intake manifold gaskets, valve cover gaskets, oil pan gaskets, and dipstick tube. But the oil pressure that you read is from the pressurized side of lubrication system, which SHOULD be separated from crankcase side. By the time the oil returns to the crankcase through bearings and rocker arms, they should be at atmospheric pressure as well.

Here's a scenario where a higher oil pressure can lead to more leaks: The higher pressure causes more flow to the rocker arms, which could pool up more in the rocker area, and if the valve cover gasket is failing, you will see more leakage there.

If your oil leak is really caused by higher oil pressure, then something is wrong with your lubrication system. The most likely place to see oil leak from too high of pressure is at the oil filter gasket, or the oil pressure sensor, or its plumbing, as those are the places immediately after the pump, and they have seals between the high pressure oil and the outside. For s few years in the early 80's, Volkswagen had a problem with excessive oil pressure in their 1.7 liter engine that caused oil filter gaskets to fail.

 

Again, I'm only speaking from my personal experience with my current Windsor motor which I built. It has a lopey cam and lower than stock vacuum. The crankcase was not venting properly and it showed on the stock oil pressure gauge. The problem was the pcv valve. Stock ford pcv valves were not functioning to my liking so through trial and error I solved the problem as I stated earlier. I would advise anyone with an aftermarket cam with long duration and LSA of 112 or below to try the hollow pcv. It's less than $5.