PCV Valve Question

Greetings Forum Friends!

As I wrap-up the engine bay vacuum lines on my 5.7 LS1, I’m confronted with the simple task of installing an “external” in-line PCV valve.

This is something that never crossed my mind during the engine build.  However, it should have at the very moment I discovered the factory valve covers did not provide adequate clearance for the rocker arms. My Holley valve cover replacements only provide an oil filler cap and a 90 degree, 3/8” nipple for a vacuum line.

I found a Beck-Arnley PCV valve on-line that “looked” like it would do the trick.  The specs didn’t include line sizes and I was surprised how small it was when I received, and that it only has a a 1/4” ID inlet and outlet.  The OD fits a 5/16” hose nicely.

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<Beck-Arnley PCV Valve>

In addition to being rather small, the BA PCV valve does not seem to have any moving parts and is like a static one-way valve vs. the rattle ball type that I’m familiar with.

So, my Forum question is…will this type of PCV valve do the job??
…and if NOT, what is the best path forward?

I have learned that an LS6 valley cover is the ideal setup for crankcase ventilation but unfortunately that ship has sailed.

Recommendations appreciated…Thanks in advance!

For what it's worth, GM switched to a fixed diameter orifice PCV "valve" on the pickup engines. I believe that was around the time they were using the DOD actuators in the valley, so the LS6 style valley cover couldn't be used.

There are a number of different ways to pursue controlling crankcase vapor management.

Hey_Allen,
Thank you for that background info. So my question now is how are the orifice style PCV units rated? I want one “big” enough to manage whatever crankcase fumes the 5.7 produces without having a massive vacuum leak.

Don't know anything about that Beck-Arnley valve.
I run the stock rattle type PCV from an early Camaro.

Raymond-P wrote:Hey_Allen,
So my question now is how are the orifice style PCV units rated?  I want one “big” enough to manage whatever crankcase fumes the 5.7 produces without having a massive vacuum leak.

I just went and did a little digging, and found the following links:
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It appears to be a 1/16" hole. The TSB advised that it should not be used on a 4.8L due to compromised idle quality, but it is listed as applicable to 5.3L and 6L engines. (The 5.7L appears to have already been "obsolete" by the time this update came about, and is not mentioned in the TSB.)
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Hey_Allen,

Thanks for doing this research! VERY USEFUL!

Just yesterday, I purchased a stock GM ball-type PCV valve ($1.85) and compared the airflow with the Beck-Arnley orifice type unit.

By just inhaling thru each valve, I can say the BA valve passes about 1/3 the air that the GM ball type valve passes. This makes sense based on the info you sent me and would explain the oil loss LS1 owners have complained about.

BTW, you cannot see through the BA valve so it must meter the airflow a bit differently than the new LS1 PVC valve with the reduced 1/16" orifice.

I'll check today and see if my local parts store carries the new LS1 unit. Then I can compare all three!

If you can't find one of the orifice PCV valves, I have one that I purchased before I stumbled across a LS6 valley cover that I'm planning to use.
I can at least look at the Dorman part number, or even send you the valve since I won't be needing it.

Hey_Allen,

That's a very generous offer! Thank you, but I found the valve on E-bay so I can get my hands on one. I also found more specs and feedback on "GM-Trucks.com"

It seems excessive oil consumption is the primary complaint, but I can't help but feel there may be other inherent engine problems that contribute to this, IE worn piston rings,...not to mention oil loss associated with use of modern conventional light weight oils which are more volatile. I only know this because low volatility is one of the many benefits of synthetic oil vs. conventional oil.

So my plan moving forward, since my engine has yet to run, is to start with the conventional GM ball valve PCV valve. At some point then, I can easily swap out the PCV valve with various alternates and see what happens.

I suggest adding a catch can. My setup went through a few iterations but ended with a dual can from Saikou Michi. The dirty side vents from from the valley and the rear of the heads just has a balance hose. Clean side catches almost nothing but the dirty side collects about a pint of nasty runny oil over the course of a track day. YMMV

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