Kind of weird pcv problem

Beagle 1

Well-known member
Joined
Mar 25, 2008
Messages
332
Location
Orange Co. Ca
I'm looking at the pcv hose on my 69 427/390 mostly stock engine and I notice that the hose looks like a cold ac hose with condensation on it. Turns out that it is oil. Not just a smooth coating, but little bits all over it.
The hose is a 3/8" high pressure fuel line that has about a 3/16" wall. I found that with the high underhood temps that the standard vacume hose would colasp, so I switched to a more robust hose about 5K miles ago. Seems to work fine, just a little large.
I get about 18" of vac at idle and the pcv valve is working.
I doubt that the oil is coming through the hose, especially since it is a vacume hose, but where would it come from? Do you think it could ooze out from the hose when the engine cools?
I guess the easiest thing is to try another hose.
Also, a few questiions on the pcv system.
There is definately a restriction through the valve. Is this normal? Is there such a thing as a high flow valve? And would this be advantages, or is the flow suposed to be restrictive? There isn't any noticeable blowby or oil fumes when I pull the valve out of the stock valve covers.
 
There is a hose rated for specific PCV use, I bet something to do with modern fuels and the gasses.....didn't used to be, years ago....

and I heard of some variations in the flow capacity for PCV valves...but forget the callouts/numbers....:beer:
 
You want to use pcv/emissions hose for that.

PCV valves are calibrated for flow. Delco units have letters underneath for the flow rate. A, B, C, D E, F, Etc.
Use the unit called out for your engine. It is a "controlled" vacuum leak per say. Your correct unit is calibrated for the quadrajet installed.
 
Makes sense, a bigger engine should flow more than a smaller engine.
It still seems weird that oil is apparently oozing through a line marked high pressure fuel. I'll look for the correct line.
Thanks guys.
 
I installed a AC Delco #cv774c equivelent PCV valve from Napa (#2-9210) that was recommended by Lars and others in some old threads. It looks the same as my old one, but obviously is different, as my base idle increased by almost 200 rpms. It is marked with a F on the bottom of the valve. I put on a American made Goodyear emmisions hose and everything seems to work fine.

FYI The counter guy at Napa told me that their store brand--Ecklin--has been sold. Hope the quality doesn't decline, or that they don't go overseas.
He also said that all the American made pcv valves are made by Standard Parts corp.
Just the opposite of like my new AC Delco master cylinder that is marked "China".
 
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