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Discussion Starter #1 (Edited)
All,
If you've seen my other thread, you know I'm going through a full engine rebuild. Well, while tearing it apart I notice a good bit of oil in the intake manifold (more than I expected with a catch can), and the machine shop later commented that it looked to be burning some oil (without me telling him about the intake manifold).

So... would like to figure out if I have an issue with my PCV, or if I'm just an idiot (more on that later).

Setup on the car was (had 7k miles on it):
- New valve spring kit with seals (heads cleaned and assembled at machine shop)
- Brand new ported intake manifold
- LS3 valley cover with PCV built in
- Holley Valve covers with PCV port on driver's side blocked off. Passenger side is clean side from intake pipe
- Elite E2 Catch Can - runs from valley cover to catch can to intake manifold
- Side note: after inspection - ring gaps were .020"

First, is there an inherent issue with my PCV setup? I'm assuming not since it's essentially a stock LS3 setup (unless I somehow did it wrong).
Second, is my current PCV setup sufficient? Do I need additional ventilation? Can I block off the return to the intake manifold and just "catch" all of the oil?
Third, (the potential idiot part) I checked my catch can maybe every other fill up, and it got to about 1/2" to 3/4" of oil in there. So would that be considered "full"? Seemed like it should/would hold more.

I'm leaning toward it being a personal problem, but with a fresh engine going in, I want to get it right.

Thanks
 

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Is your catch can open , or do you have it filled with something to catch the oil in the vapors. SS pot scrubbers in my choice to put in the can. You can also put your original LT rocker cover on.
 

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Discussion Starter #3
Here is the inside of the E2. So, I guess you'd say it's "open-ish"

 

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Discussion Starter #4
Still trying to sort this one out if at all possible.

Can positive valve overlap (5.5 degrees in my case) cause oil to make its way back into the intake runner/intake manifold? Seems like the answer would be yes, especially at idle or lower engine speeds.
 

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I'd start with the revised driver side (LHD/G8) valve cover first: https://www.g8board.com/forums/115-intake-fuel-tech/227042-6-0-intake-manifold-oil.html#post3114690

If you have a silver throttle body blade (2008-2009.1): P/N 12570427

If you have a bronze throttle body blade (2009.5+): P/N 12642655

I just purchased P/N 12642655 for my GXP and will install it this weekend while I replace the throttle body gasket, intake manifold gaskets, intake manifold foam pads, valve cover gaskets, and valley cover gaskets. Grommets included.
 

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Did you remove and block off the AFM relief valve on the Oil pan? It sprays oil into the crank area. GM had a diverter cover for it to direct the oil back to the pan. I would block off the PCV on the valley cover and use the one in the rocker cover. Look and see if trhe rocker cover one is restricted to just a small hole at the bottom of the nipple.
 

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Discussion Starter #7
Did you remove and block off the AFM relief valve on the Oil pan? It sprays oil into the crank area. GM had a diverter cover for it to direct the oil back to the pan. I would block off the PCV on the valley cover and use the one in the rocker cover. Look and see if trhe rocker cover one is restricted to just a small hole at the bottom of the nipple.
No, the relief valve is still there. I did talk to my machine shop about blocking that off. Is that really a thing for AFM? Does the LS3 not have a pressure relief valve?

Why change from the valley cover to the rocker cover?

Side note: my machinist is blocking off the DOD oil bosses on the top of the block.
 

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Non AFM engines don't have the extra relief valve, they block it .The main oil pressure relief valve is in the oil pump. GM came up with the diverter for the AFM relief valve because of complaints of excess oil consumption. Ding ding ding. Don't waste your time blocking the bosses, the new cover has O-rings to seal them from leaking. AFM engines use the rocker cover for the PCV because it is farther away from the crank and the source of the oil spray you are picking up. Use the rocker cover to reduce the oil you get now. The fix is to remove the source of the oil spray in the oil pan, the relief valve
 

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Discussion Starter #9
Non AFM engines don't have the extra relief valve, they block it .The main oil pressure relief valve is in the oil pump. GM came up with the diverter for the AFM relief valve because of complaints of excess oil consumption. Ding ding ding. Don't waste your time blocking the bosses, the new cover has O-rings to seal them from leaking. AFM engines use the rocker cover for the PCV because it is farther away from the crank and the source of the oil spray you are picking up. Use the rocker cover to reduce the oil you get now. The fix is to remove the source of the oil spray in the oil pan, the relief valve
Thanks! I didn't realize the oil pan valve was an AFM only thing. That's easy to do. But sounds like I can keep using the valley cover PCV if I block it off. Or still go with the rocker? I should add that I'm going LSA eventually, and I thought I understood that LSA needed the valley cover PCV. Could be wrong though.

The bosses... the shop isn't charging me extra for it. Just gonna do it while it's all apart.
 

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The LSA needs a flat valley cover to fit the blower. You can take the PCV from where ever you want. It doesn't matter. I would want to limit the number of hoses at the front of the engine near that blower belt.
 

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Improved Racing sells the plug to replace the relief valve. If you have gone to a standard volume high pressure pump it is down right dangerous to leave that relief valve in.
You put that black plug in the pan and you won't be loosing oil pressure internally and having extra oil vapour sucked into the engine
 

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Discussion Starter #12
Improved Racing sells the plug to replace the relief valve. If you have gone to a standard volume high pressure pump it is down right dangerous to leave that relief valve in.
You put that black plug in the pan and you won't be loosing oil pressure internally and having extra oil vapour sucked into the engine
Ha! That exact part has already been delivered to my machine shop. However, there is quite a bit of debate out there regarding which oil pump to run. Improved Racing says to go standard volume pump versus high volume for AFM. I called Melling and they said stick with a High Volume pump (part number M365 or 10355).

In talking further with my machinist, we're going to stick with the pump I currently have: GM 12612289 High Volume pump. It's only 7k miles old and in perfect shape.
 

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If you have deleted the AFM, then the original pump is overkill. LS3 does not use the L76 high volume pump. As long as you plug that relief valve your troubles of oil in the intake will be reduced
 

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Discussion Starter #14
If you have deleted the AFM, then the original pump is overkill. LS3 does not use the L76 high volume pump. As long as you plug that relief valve your troubles of oil in the intake will be reduced
Yeah, that's the bit that was confusing. Some sources said that early LS3's did not have the AFM relief valve, but the later ones do. That would suggest the later versions had the higher volume pump. 🤷‍♂️

Then 2 calls to Melling both said adamantly that I should retain a high volume pump. I explained the full rebuild, blocked AFM valve, etc. Still... keep the high volume pump or risk low pressure at idle.

At this point I'm keeping the pump I have and we'll see how it goes.
 

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Yeah, that's the bit that was confusing. Some sources said that early LS3's did not have the AFM relief valve, but the later ones do. That would suggest the later versions had the higher volume pump. 🤷‍♂️

Then 2 calls to Melling both said adamantly that I should retain a high volume pump. I explained the full rebuild, blocked AFM valve, etc. Still... keep the high volume pump or risk low pressure at idle.

At this point I'm keeping the pump I have and we'll see how it goes.
I replaced the oil pump in my GXP as part of replacing the oil pan gasket, front cover gasket, tensioner, water pump and other various items when I replaced the harmonic balancer with a Fluidampr.

I decided to stay with the normal Melling pump (M295), which is a replacement for the pump that came out, and have had no issues.

I had no issues with the OEM oil and water pumps but decided to change them out while I was in there.
 
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