Which PCV Valve to use???

[Ace17]

Yeah I'm not opposed to trying any of these suggestions, because at this point I'm starting to run out of ideas.

Not to hijack my own thread, but I'm currently dealing with a oil pan leak right at lip where the oil pan meets the timing cover. I've replaced the gasket at least 3 times and it still leaks(the one-piece felpro gasket). While the engine runs, it's totally fine, but as soon as I shut it off, it squirts out of the bottom lip of the oil pan. I've heard from several people that it could be because of a buildup of crankcase pressure, so that's I'm currently looking at the pcv valve system.

Do you guys have any more suggestions as to what it might be???

[Fast355]

Yeah I'm not opposed to trying any of these suggestions, because at this point I'm starting to run out of ideas.

Not to hijack my own thread, but I'm currently dealing with a oil pan leak right at lip where the oil pan meets the timing cover. I've replaced the gasket at least 3 times and it still leaks(the one-piece felpro gasket). While the engine runs, it's totally fine, but as soon as I shut it off, it squirts out of the bottom lip of the oil pan. I've heard from several people that it could be because of a buildup of crankcase pressure, so that's I'm currently looking at the pcv valve system.

Do you guys have any more suggestions as to what it might be???

With the engine shut-off the crankcase pressure will be gone in a fraction of a second.

My guess is its likely leaking at the timing cover or at the bolt that intersects into the fuel pump pushrod cavity if you have changed the pan gasket 3 times.

Do you have the oil pan reinforcement bars in place?

Did you clean the block where the pan sits completely with carb or brake parts cleaner and put a bead of RTV on all 4 corners where the pan gasket meets the timing cover and the rear main seal housing?

Stock vortec timing cover is also one time use. Once its torqued into place and removed, you throw the timing cover and bolts in the trash and get a new one. If you reused the cover swapping the cam it could be your leak source. I have a Holley Aluminum cover on my L31 based 383.

[PlayingWithTBI]

You should have a PCV valve on one valve cover going to the base of the throttle body, and on the other side should be an open hose that goes from the valve cover to the back of the throttle body neck.

[JCampbell]

I just finished an L31 TBI build in my 86 K20. I'm using the stock LO5 PCV.

One interesting thing I learned is that if you don't have a proper vent on the other valve cover to allow clean air into the crankcase, you will build a vacuum in the case and it will pull air in through the rear main seal. It will cause an intermittent squeak or squeal that will drive you crazy.

I lost the plastic vent tubing that went from the valve cover to the air cleaner and couldn't find a breather to fit, so I temporarily plugged the hole with a spare PCV valve. The squeaking freaked me out. Thought I was loosing a bearing or something.

[Ace17]

Fast355 - You've got an aluminum cover on your vortec engine??? I was looking around for a metal cover at the time of building this engine, but I couldn't find one. I never liked the idea of putting a plastic timing chain cover on an engine; plastic has a tendency to warp with age.

Yep, I've got the reinforcement bars in place, and I spent an hour cleaning everything up with brake cleaner and acetone. When assembling I put 4 dabs of black rtv in the corners where the block meets the timing chain cover. This area on the engine is actually bone dry.

I normally don't touch the timing cover when I change the oil pan gasket, because there doesn't seem to be a leak anywhere above the lip of the oil pan. It's the strangest thing(I might shoot a video of it eventually), but whenever I am running the engine for a while, and I turn it off, about a tablespoon of oil gushes from the middle of the lower lip of the timing chain cover/oil pan junction.

[Fast355]

Fast355 - You've got an aluminum cover on your vortec engine??? I was looking around for a metal cover at the time of building this engine, but I couldn't find one. I never liked the idea of putting a plastic timing chain cover on an engine; plastic has a tendency to warp with age.

Yep, I've got the reinforcement bars in place, and I spent an hour cleaning everything up with brake cleaner and acetone. When assembling I put 4 dabs of black rtv in the corners where the block meets the timing chain cover. This area on the engine is actually bone dry.

I normally don't touch the timing cover when I change the oil pan gasket, because there doesn't seem to be a leak anywhere above the lip of the oil pan. It's the strangest thing(I might shoot a video of it eventually), but whenever I am running the engine for a while, and I turn it off, about a tablespoon of oil gushes from the middle of the lower lip of the timing chain cover/oil pan junction.

Mine has the hole for the crank sensor but Holley makes it both ways. If you ever want to run a sensor in the one cast shut, a relatively simple machining process could open the hole. Then again the whole cover was reasonably priced. ~$65.

Are you sure the timing cover is not cracked or missing part of the rib that holds the gasket into place.

[Ace17]

Yep, the bottom of the timing cover is in good condition. It actually looks like it's leaking from bottom of the oil pan gasket mating surface, as opposed to the top where the gasket meets the timing chain. I'm gonna be out in the garage a little later, and I'll see if I can shoot some pictures to show you what I'm talking about. If I can, I might even get my dad out in the garage and I can film the oil coming out of the oil pan front lip as the engine is shut off.

[Ace17]

UPDATE! Okay, it looks like it's leaking a little higher up than I thought! It's coming from the upper corner of the oil pan and leaking down. I put black rtv there(as seen in the video), but it didn't seem to make a difference.

https://www.youtube.com/watch?v=WYI_sdXgBI8

https://youtu.be/4-C9S7T0MDc