RedRascal

I am transplanting a 5.3L LS engine that came from a 2007 Silverado, an LC9 donor. I plan on using the stock truck intake and electronic throttle body. The problem that I am having concerns the attachment of the PCV fresh air hose. There is a hose attachment fitting on the front passenger side valve cover right where it is supposed and expected to be; however, there is no attachment point on the intake manifold where I expected it to be which is behind the stock electronic throttle body. There appears to be a factory "blocked" port in that position. I can't find any PCV diagrams on line or in my manual that shows how and what that fresh air hose is attached to. Can someone help with a photo, web link, diagram or explaination? Thanks in advance!!

R6cowboy

iTrader: (3)

Here's an image indicating the routing of that hose. Your intake manifold doesn't have that port on the passenger side near the top of the intake?

RedRascal

Thanks R6cowboy! Right there in your photo that shows the connected hose is, what appears to be, an OEM BLOCKED port in the manifold. Worse case, I can open the port and install a fitting, which is a very helpful insight. Now I'm curious how this particular model engine was "plumbed". The donor engine was one of those VVT engines and I'll bet that is why the plumbing is different. Thanks again for your help.

Michael Yount

iTrader: (1)

Be sure the crankcase connection (to valve cover it appears from the photo) has an orifice in it. If the intake pulls vacuum through that valve cover connection, where does make up air enter the crankcase? Trying to educate myself -- the PCV set up on my LS3 is entirely different.

cam

iTrader: (9)

Thats the clean side of the PCV. You can run that to the intake before the trhottle body, but AFTER the MAF. Its important to not run that directly to manifold vacuum thats what the other side "dirty side" is for.

So run the drivers side valve cover with a ported baffle instead of a PCV to manifold vacuum, and the passengers side to the intake system IN FRONT of the throttle body, but AFTER the Maf.

If you run it any other way it can mess with the MAP sensor values and/or have oil consumption issues

RedRascal

First, thanks to: cam, Michael and R6cowboy for the comments. I have a plan now and here is what I think would be my best solution. I will connect the fresh air port on the passenger side valve cover and the center engine valley cover, which also has a port, via a Y-fitting and connect this line to the planned air intake tube in front of the throttle body but behind the MAF sensor. In that matter I can utilize filtered air from the OEM filter box that came with the donor engine.

On the driver side valve cover where the stock PCV valve connects and routes to its connection point on the intake manifold looks like a good point to install a catch can. It seems installing a catch can in that circuit between the PCV valve and where it connects to the intake manifold would capture the blow-by contaminants, some water vapor and other stuff before it had an opportunity to reenter the intake stream.

Anyway, that seems like the best solution to allow the engine to breath using fresh filtered air, still retain the stock PCV setup while installing a catch can to capture the blow-by contaminants.

cam

iTrader: (9)

Connect either the valley cover or the drivers side valve cover to manifold vacuum. DO NOT connect the valley cover to the clean side or y in with the passenger side.

The valley cover port was a replacement ( for a time ) for common "oil in intake" issues early LS1's had when they utilized a true PCV valve. The best fix imo is to use the orfice pcv or the 05+ drivers side valve cover and run that direct to manifold vacuum without catch can at first ( not needed if the engine is sound and you are naturally aspirated )

the clean side is to allow intake of vac to relieve any possible seal problems so it is plumbed into ported vacuum in the TB or usually into a fitting in the air intake tube as mentioned earlier before the throttle body, but after the maf. This keeps the map sensor values from possibly going wonky.

The valley cover was used to completely replace any vac port on the drivers side rocker cover so if you want to use that? Plumb directly to manifold vacuum and plug the drivers side pcv port completely.

Newer systems all use the orfice style in lieu of a true PCV because it works, and prevents much oil problems. The newer valve covers also have a better baffle for oil splashing and drainage.

RedRascal

Thanks cam! Your explaination makes perfect sense and is a much simplier installation. That's the way I'll set everything up. Thanks again!

Michael Yount

iTrader: (1)

BTW - if you decide to run the Holley replacement valve covers (I like the coil attachment mechanism better) they have the proper orifice in them.

RedRascal

Thanks Michael;
I will be running the stock valve covers that were on the 2007 donor engine. I'm saving this thread and will try the Holley VC's if the stock units do not work properly. Thanks for your advice.