So I am taking my intake manifold off to get at the oil pressure sensor since I am having some oil pressure issues(giving this a shot before giving up the ghost and going after the pick-up tube O-ring) and to my surprise, I find large amounts of oil in the intake and in the intake runners. I am just off of a rebuild after a broken timing chain episode, however when I first tore the car down for the TC failure, there was almost no oil in the intake or in the intake runners. I am running a RevExtreme catch can setup that worked PERFECTLY prior to this rebuild. What could cause this? The catch can was hooked up correctly. I don't see how oil could enter the intake any other way.

Update at bottom of Page 4 regarding leakdown test







This is what resulted after a quick wipe inside my intake manifold with my thumb

 

Did you clock you rings straight up? Depending on the cam it could be caused by reversion. How much oil is there in the intake?

 

Clock my rings? I am running the same cam as I did before the rebuild. I did not rebuild the bottom end, I just had the heads checked(the guides, there was no porting done) and put a stronger chain in. The stock rods and pistons are still inside the motor. That coating you see on my thumb is pretty much on every surface inside the intake manifold.

 

Only way oil can get into the intake "LIKE THAT" is through the PCV lines. Is the oil also like that just inside the throttle body blade area.

Do you still have the line that goes from your passengers side valve cover to your intake?

 

No, I was instructed to plug the line from my passenger side valve cover to my intake for this catch can. The fresh air source is a oil cap with a breather on it. There is no oil "like that" just behind my throttle blade. It is definitely coming in through the PCV, there is just no other way right? I am wondering if my mind is playing tricks on me, but that is a large amount of build up correct? Especially for a system with a catch can?

 

Thats a crazy amount of oil. You will start to get build up on your pistons after shutdown each time and then that build-up will get hot spots and you will then get detonation/pre-ignition.

I was just asking about that crankcase breather line, it should be capped if you have the breather and catch can.

Looks like that catch can isn't working and maybe your PCV valve is staying wide open all the time.

Here's what you'll get soon: detonated at normal operating temps becauxse of hot spots pre-igniting the fuel/air.


Cleaned:

 

I checked the valve stem seals as I best I could and they all still look plenty seated and the little spring at the top is still on all of them. I assembled these heads off of the car, so it was easy to make sure the stem seals were fully seated before throwing the springs on. The only thing I could think of is I may have set something oily on the intake mani while it sat for 2 months. I don't know, but everything else looks fine. Guess I will have to put her back together and check again after some miles to verify.

 

Its just wierd that you wiped your finger inside the intake and it was covered with oil. The intake ports are angled so you really can't put them down on the ground/floor, they wouldn't touch the floor. I think after just a couple drive cycles, whatever wet oil was there would be burnt away, not just raw fresh oil like that.

Is that oil on both sides (both heads)?

Hows the catch can look inside?

PCV valve may be stuck open?

 

I don't think it has anything to do with the PCV valve. I wasn't even using one and never had any oil usage issues like this. I would recommend running your PCV system this way...

From the valley cover direct to the intake, from the pass side valve cover direct to the throttlebody. Get rid of the breather because its been found that at high rpms a breather can actually allow so much airflow that it can strip away the protective oil film. You can just y-joint the valley/valve cover to the catch can and into the intake also if you want to use your catch can. But i've never had to run one if the system is setup properly. I would also run a thicker oil as well, at least 10w30. Thinner oils will aerate and vaporize a lot more.

 

Actually, just cap the breather, and see if it helps.

 

Really the only thing that could cause that is blow by which the catch can should catch to some degree.

Have you checked gaskets?? Maybe you are pulling oil in through the gasket.

 

I made sure the catch can PCV valve is still working and it is. I emptied the catch can and your typical residue came out of it, but nothing like the oil I saw in the intake. I am not sure whats going on, which seems to alway be the case with the problems my car has. Can anyone tell me if re-using the valve stem seal the Comp 921 spring kit comes with is a bad idea? They only had 8k miles on them from my old setup and looked perfectly fine.

 

Guys, remember that I ran this exact setup prior to my stupid timing chain failing and it worked perfect. Ugh, it has to be something other than my catch can/PCV setup....diagnosing this crap is such a pain. Is there anyway to verify my valvestem seals are good without removing the spring? I made like 1000000 percent sure to make sure those suckers were completely seated on the guide before install the valves from teh bottom.

 

But all 8 of them leaking the same??????????????

Yup, tracking down a friggin mystery sucks.

 

I tell ya, someone's got to make an air pump and a couple hoses with a catch can that circulates air through the crankcase. End this whole oil through the intake stuff. How hard could it be?

 

If your valve stem seals are leaking its going to go into the cylinder not the intake right? Is the intake craked or something maybe pulling oil out of the valley into the intake? I've never had a LS engine apart enough to know alot so these are the only ideas that i have, besides pvc related things. Goodluck

 

How many miles on this refreshed setup, and the old?

 

Valley and intake don't touch.

 

I have maybe 30 miles on the new setup since I found out the oil pressure is about 10psi low. The old setup had 8k miles of flawless operation until the tc broke

 

So can it be confirmed that since I have equal distribution of oil in every intake port, that a valve stem seal issue is unlikely? Additionally, there is no oil on the valve stem itself nor on top of the valve as seen in pic 3. This couldn't some how be the result of lower than normal oil pressure could it?