Rear main leaking, too much crank pressure?

[mark2215]

I'm running a Golen boosted 4.6 stroker and Ripp Vortech supercharger @ 12psi. The rear main seal is leaking after a couple hundred miles and Golen claims it's because I don't have enough crank case ventilation. The supercharger kit came with a 30psi pcv valve and the front valve cover breather is routed into the supercharger inlet filter. Do you think the leak is due to inadequate ventilation? How could I increase the ventilation?

[SilverXJ]

Where is the PCV valve routed to?

[mark2215]

From the rear valve cover vent to the top of the intake manifold.

[SilverXJ]

Interesting use of the PCV valve being that it sees boost. I would make sure the PCV valve is working first.

However, being that the front elbow/breather is before the supercharger the crank case should not be seeing any pressure. Are you sure you have the open elbow in the front and not the smaller orifice one?

[mark2215]

the rear elbow has a flat tab that turns and locks into a channel on the rear valve cover hole so I'm sure they are in the correct places. Is it possible that I'm getting enough blowby that the front breather is not able to vent fast enough? Would the dipstick pop out before the rear main seal would leak? The engine doesn't leak while idling but after a high rpm/boost run there is oil leaking out of the rear main/oil pan area, can't be positive exactly where it's coming from. I have tested the pcv and it's working properly and installed in the correct direction.

[SilverXJ]

I'm having a hard time visualizing the exact routing. Could you post a pic of your engine bay?

[mark2215]

enginebay.jpg

[wjtom]

if i got the picture correct the pcv is mounted by the intake?if so the stock elbow in the back of the valve cover has a orifce in it acting as a pcv valve.Youre going to have to take that out for the actual pcv valve to work right.

[jeepxj3]

Is that like a direct boost leak from the intake manifold to the rear valve cover vent? 12psi?

[mark2215]

there is a 30psi pcv connected to the manifold, then the plastic tube connects to that and runs to the valve cover. The pcv is basically a check valve that allows air to be drawn into the intake when vacuum is present but prevents boost from traveling from intake to valve cover. The rear plastic elbow going into the valve cover has been drilled out.

[SilverXJ]

While it is an odd setup I don't see why it wouldn't work. That is if the pcv valve is working correctly, which you said it is. It also looks like the front elbow is the correct open style as they are shorter than the rear ones. I would verify that the front is in fact open as well as that there are no obstructions in any of the lines. I would also question the smaller line off the front elbow. If everything checks out I would remove the dipstick and hook a vacuum/pressure gauge to the dipstick tube. Ducttape the gauge to the windshield and do a run and see if there is pressure building. Just because the leak happens after a run doesn't mean there is pressure in the crank case. Could be just the oil getting thinned out and finding a leak point or the oil moving under a heavy accel.

Also, you said that the elbow has a locking tab that you rotate to seat. That valve cover doesn't take the kind that rotates. They simply just push in. Also, from the pic it looks like you are using the steel spacers and rubber grommets on the valve cover but its hard to tell.

I would also verify that the leak isn't coming from someplace else. The valve cover gasket could be leaking, the RMS, or the pan gasket. Make sure that that metal strap is on the rear of the oil pan. Make sure all the bolts are torqued to spec. Was there RTV used on the main cap when it was installed? Also, on the oil pan the new gaskets don't have the little nubs that go into the voids on the sides of the rear cap. Those voids must be filled with RTV prior to installing the gasket.

[SilverXJ]

BTW, what power steering pump is that?

[mark2215]

The valve cover does in fact have the lip to lock in the rear breather elbow. I could take a picture if you'd like. I can blow through the front elbow easily so it is clear. I'll work on hooking a pressure gauge to the dipstick tube this weekend to check for pressure while driving. I am using the spacers and rubber grommets. There is no oil on the back side of the engine above the bell housing and I've packed rags in there to see if any dripped down while driving so I'm sure it's coming from either rms or oil pan.

Golen installed the oil pan so I do not know if they used rtv in the proper places. I have verified torque of the oil pan bolts. I don't see a metal strap in the back of the oil pan, I'll have to take a look at the old motor and see if I can take it off that one. I need to change the oil soon so I think I'm going to pull the oil pan at that time and reseal everything. I'm debating if I should just go ahead and change the rear main while the pan is off.

The power steering pump is from PSC and came with my hydro-assist steering setup.

[mark2215]

Ok, I had a few extra minutes so I ran out and took a look at the old engine. Sure enough I see the metal strap on the back of the oil pan. I took it off, cleaned it up and put it on the new motor. Still leaking. I'll try hooking up the gauge next and see what that tells me.

[SilverXJ]

I wouldn't jump to conclusions just yet. Report back later if that did really fix it. It would be interesting if it did.

I do have a couple more questions on your build. What is the intake manifold off of? I only ask because the IAT hole isn't drilled & tapped. And the throttle body? It doesn't look stock nor any modified one that I have seen much of.