Turbo Z34 Monte Carlo Excessive Crankcase Pressure

[pwmin]

I started tearing apart the engine and pulling the turbo on the Monte intending to replace the valve seals.  I think I'm going to fix the oil pump drive leak, replace the intake gaskets and convert to the 96-97 setup for LIM/UIM/ valve covers. I tore everything apart down to the valley cover and none of the PCV passages or the hoses were clogged. You can see most of the PCV in one of the pictures.  Is there a better way to run the PCV since the "factory" system doesn't seem to be keeping up?  In the past, I've replaced the PCV valve, added a check valve (tried both ways, tried a simple catch can and eventually went back to the breather filter, but it still smokes.  This is mostly temporary until I have the time and space to do the whole 284/97 LQ1/OBD-II swap I'm intending on.

Also, the 96+ doesn't have this vacuum setup on the plenum. How is it supposed to be hooked up?  It's broken, anyway.  Anyone have a 96-97 vacuum diagram?  I might have one somewhere, but I'm not sure.

Edited March 4 by pwmin

[pwmin]

I actually found something useful from Shane (as in something old that actually still comes up instead of "404") 

"The trans vac line is a hard line that plugs behind the TB nipple. I actually capped a few of the nipples (didnt hook up evap crap and used original trans line w/ adaptor). Like i said i removed all the EVAP crap and simplified it a ton.

Let me see if i can find the pics or take a new one.. when the board changed over my garage pics went somewhere i dunno where..

here is how mine is: (all that is needed)
* Stock Trans line to the stock intake plennum adaptor (passanger side, just poped the freeze plug out and bolted the adaptor in its place)
* FPR and HVAC source plug to the connector on the intake arm w/ the brake booster hose
* Front Valve cover attaches to the nipple on the front side of the TB to the "L" shaped hose like in the pics from the swap.
The rest are capped.

You can run the '96 trans line to one of the ports on the TB if you want to do it how the '96 OEM setup was originally. My turbo setup got in the way so i ran the old trans line."

[Schurkey]

Where does the PCV system get it's vacuum?

Deleting the evaporative emissions devices is just silly.

[pwmin]

9 hours ago, Schurkey said:

Where does the PCV system get it's vacuum?

Deleting the evaporative emissions devices is just silly.

from the plenum, I believe.  There's a nipple on the bottom.  

I'm more interested in the other part.  It does say that he popped the plug out where the vacuum fitting in question went on the old manifold, but it's broken, so I'm probably going to have to go somewhere else for those.

[Schurkey]

The plenum is under turbo boost pressure.  No vacuum there.

No wonder you have crankcase pressure.  You need to re-route the PCV hose so it's ahead of the turbo.  Or create a vacuum-valve-controlled "Y" so you get plenum vacuum before the turbo spools up, and the valve switches to turbo suction side after the turbo spools.

Either way, the "fresh air inlet" side of the PCV system needs to vent over-pressure into the turbo inlet somewhere far enough up-stream that it's got no suction in the plumbing.

Edited March 7 by Schurkey

[pwmin]

12 minutes ago, Schurkey said:

The plenum is under turbo boost pressure.  No vacuum there.

No wonder you have crankcase pressure.  You need to re-route the PCV hose so it's ahead of the turbo.  Or create a vacuum-valve-controlled "Y" so you get plenum vacuum before the turbo spools up, and the valve switches to turbo suction side after the turbo spools.

Either way, the "fresh air inlet" side of the PCV system needs to vent over-pressure into the turbo inlet somewhere far enough up-stream that it's got no suction in the plumbing.

I have to look at it again.  I took the plenum off and can't recall for sure.  Planning on at least starting to put it back together tonight.

[pwmin]

I'm going to print off the 96-97 diagrams tomorrow at my dad's shop.  This is off of my car.  Unfortunately, I don't have a factory or aftermarket service manual, so I'm going to have to change that.  

Edited March 8 by pwmin

[pwmin]

[Schurkey]

^^^ THAT's not correct.  

Am I seeing this correctly?  Maybe there's a trick of perspective that makes things look connected in the photo when they really aren't.

You've eliminated the PCV in favor of a craptastic crankcase vent via an oiled-gauze filter.  Looks like the two valve-cover vents, AND the PCV suction hose are all tee'd together with the filter, AND the connection to the air intake hose still in place with yet another tee.

There's no vacuum to the PCV valve, so it's useless.  The filter and the air intake hose are both acting as a vent.

[pwmin]

3 hours ago, Schurkey said:

^^^ THAT's not correct.  

Am I seeing this correctly?  Maybe there's a trick of perspective that makes things look connected in the photo when they really aren't.

You've eliminated the PCV in favor of a craptastic crankcase vent via an oiled-gauze filter.  Looks like the two valve-cover vents, AND the PCV suction hose are all tee'd together with the filter, AND the connection to the air intake hose still in place with yet another tee.

There's no vacuum to the PCV valve, so it's useless.  The filter and the air intake hose are both acting as a vent.

Yeah, looks like they're supposed to be hooked up in different spots.  That's the way it was when I got it.  Guess I should have looked at the diagram a long time ago well. It did run for a long time before it started smoking. Not when I had it but after it was built

Edited Sunday at 02:29 PM by pwmin

[pwmin]

After I put the rear 97 cam cover on, I realized that it doesn't have a vent port.  Trying to figure out if I should run the older one with it or run the newer one without it? I keep going back and forth.

[White93z34]

Whats your reason for not wanting to do it?

Seems to me you'd have more downsides then upsides not having it from excessive pressure to blown out seals.

[pwmin]

Just wondering if there's a reason they deleted it, but I'm going to put the old one back on with the extra port.  

[pwmin]

Now I'm finding out that the port isn't the only difference.  The spark plug tube gaskets are a different size and the new spark plug wires don't work with the old cover. 

[pwmin]

And the port on the rear valve cover interferes with the 96-97 upper plenum.  

[Schurkey]

Shouldn't need more than one vent on a single valve cover.  No idea why the original design had two.

But re-routing some of that PCV hose mess will likely eliminate any crankcase pressure.

Edited 2 hours ago by Schurkey