Crankcase Pressure

[Michelle]

So while tuning the now boosted '90 the other day, Adam noticed a lot of oil "leaking", which led to some researching and asking around - it appears my crankcase has too much pressure.

I was looking through a few old threads about it, but they are 4+ years old.

Any recent techniques or techniques that have been working well long-term?

I have a track event at Autobahn towards the end of May and I obviously don't want any oil on the track.

PS - Don't yell at me. I'm new to boost.

 

[93rev2sev]

How have you got your PCV set up? If it's still hooked up to the throttle body, that explains everything. Disconnect it, plug the port on the TB and put a breather filter on the end of the hose.

 

[frosho]

Or route the PCV to the air filter.

 

[Michelle]

How have you got your PCV set up? If it's still hooked up to the throttle body, that explains everything. Disconnect it, plug the port on the TB and put a breather filter on the end of the hose.

Yeah, what you said.

As a breather filter going to be enough?

 

[SHOtime2511]

I'd use a catch can setup.

 

[Michelle]

I'd use a catch can setup.

Any good pics or instructions on the best route to do that?

 

[yamahaSHO]

To be clear, you will need to disconnect your PCV (air/oil separator at top of block) and CCV (front valve cover) in order to keep from shooting seals out the engine.

 

[91PDXmocha]

Take the intake off and do a nice job sealing everything . Cap off all the throttle body ports and run the pcv from between the valley and the front valve cover out to catch can or to a small filter set up .

 

[SHOtime2511]

That line that goes from the valve cover to the TB,just route that into a catch can
you will catch all kinds of ugly stuff.

 

[Sho Amo]

Heres mine. One side is from the valley, the other from the valve cover. The breather on top ideally should get vacuum from before the blower.





Edit forgot the pic lol

 

[Off Road SHO]

Run the valley 1/2" hose to a vent filter under the car. If you have more blow-by than a 1/2" hose can vent to the atmosphere, it's time to be thinking of a new ring and valve job. If you're in an emissions state, block off the TB port where you disconnected the PCV hose, and then put a fake hose back on the port and run it back down into the V of the engine.

The buggy guys didn't understand the PCV system on SHO's so they would just drill two holes, one in each valve cover, weld on 3/4" bungs, and then run those to a filter. The problem with doing it that way is that those locations are too close to flinging oil (even the one on the front cover with the air make-up baffle) and would get quite a bit of oil carried along with the blow-by gasses.

The stock crankcase vent path on the SHO is long, zig-zaggy and has a separator built in. Very well designed in my opinion.

Tom

 

[somedude_001]

As mentioned by a couple other members. Make sure you are venting both of your crank case vents to atmosphere. I didn't vent the one under the TB initially because I didn't know of its existence and that caused me to pop a cam seal out of place. That was a messy mistake on my part. If the vent in the valley is still connected to the TB then not only do you not have it venting but you have a 1/2" boost leak into your crank case. Boost response will improve when you take care of this.

 

[Michelle]

Well catch-can is installed. Re-tuned it today, but still had oil leaking and "squirting". It appears to be coming from the area where the dipstick tube is bolted in. If you look at the picture below, the dipstick is "bent" quite a bit because of that piping. I'm planning on getting a longer silicone piece to go from the blower to that pipe to push it farther away from the dipstick.

I did remove the oil pan, clean it all up, and reinstalled it. The leaking is from the same spot as last time, but upon further investigation and with Adam under the car as I revved it up in neutral, he heard "hissing" and saw small bubbles from where those two bolts are.

 

[turbosho]

Ideally the crankcase should have an inlet and an outlet.

The inlet should have a breather filter and the outlet should go to a catch can and then to the inlet side of the blower or to the exhaust for a venturi effect.

Doing it this way ensures proper ring seal and never any blown oil seals/gaskets.

something like this

 

[Michelle]

Going to do a leak-down and compression test after work tonight. Hopefully that will tell me if I have crazy blow-by or something going on inside the engine which is accounting for such pressure in the crankcase.

Also, thanks to some Skyping with Josh, I learned that there is in fact a gasket for the dipstick tube. We'll check that out as well and ensure a good gasket is there, especially since the tube was tweaked a bit with the piping.

Keeping my fingers crossed and staying hopeful.

 

[Michelle]

Removed dipstick, created gasket (no gasket was found upon removal), reinstalled dipstick with gasket and some RTV, removed handle of dipstick since it was hitting the pipe, and..... no leaks so far! Will take a run later with more boost opportunities. Didn't want to jinx it.

 

[SHOspazz92]

What about this, Guys?

Any thoughts on this?

-Sam

 

[Sho Amo]

its good, gets vacuum to the crankcase under boost. that is weird tho. whos car is that? id like to see more pics.

 

[91PDXmocha]

Is that your SC car Sam ?

 

[SuperchargedSHOguy]

Right off the bat I like the FPR Sam!