Help with Crankcase Ventilation

A

APWCU

New member
I have a 98 12v that's just a street toy with some racing every now and then. I typically don't run it too hard for long on the street but recently I held into it on a good stretch and it covered the underside of the truck with oil.

Mods are 64.5/s480, 5x20 infinite performance injectors, hamilton stage 2 street head with HD pushrods, built Goerend auto, 7mm delivery valves, 4K gsk, rack plug, arps, factory fuel system with extra Walboro 392 from sump at tank.

I am burying my 100 psi gauge so I can't tell actual boost but I don't think it's much higher than that. When i first did these mods it covered the underside in oil so I added a valve cover vent to a separate aluminum tank with 2 decent size filters and I still have the factory blow by tube. It obviously came out of the blow by tube when this happened. Is my only option adding a tappet cover with 2 ports for extra ventilation? It doesn't blow out any in short runs but if I hold into it until overdrive and it runs over 100 psi it must really be pushing out.

I apprecite any advise. Thanks.

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Your post interests me. I have a good friend with a built up CR that too is puking oil. Not out the breather tube like yours, it’s his catch can setup.
Engine recently built, mild upgrades such as yours, but why does it burp so much oil??

I’ve seen trucks built to the same caliber and not have this issue.
 
I made an evac setup going to the hood stack, never looked back since. I used to have to tie down my dipstick before and my catch cans were half full.

I never understood why they're not as prevaliant in diesel as the gas world. Works perfect, also will end oil leak issues.

I bought the kit from summit.
 
I second this, venturi evac to hoodstack from the valve cover. also run 2 catch cans from 2 vents on valve cover and vent on front cover. They let it breathe at idle/low rpm and prevent sucking a gasket at high rpm. this did away with my leak problems entirely and have no issues racing and never been kicked from track for puking oil. I did my setup after I saw how well it worked for Jasonc.
 
I actually found a vacuum line disconnected at the vacuum pump where I was messing around with the battery the other day. I'm hoping this was mainly my issue. The blow by seems to go way down after hooking the hose back up.



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Vincejax said:
I second this, venturi evac to hoodstack from the valve cover. also run 2 catch cans from 2 vents on valve cover and vent on front cover. They let it breathe at idle/low rpm and prevent sucking a gasket at high rpm. this did away with my leak problems entirely and have no issues racing and never been kicked from track for puking oil. I did my setup after I saw how well it worked for Jasonc.
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I misspoke, my vents are on tappet cover and front cover. Evac only with one way check valve on the valve cover.
 
I had the same issue with my 24 valve, took Jasons advice and did an evac setup into the exhaust, haven't had a problem since.

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I ran 2 out of valve cover into the exhaust with my old worn out engine and was getting oil in the stack after hard pulls, so when we built the new engine, I just ended up running 2 out of valve cover and one from front cover into a catch can with filter.

I like this setup much better. The way I see it, if it ever does puke on the track, at least it will go into a can instead of under the truck or on the track....
 
Mudn_1 said:
I ran 2 out of valve cover into the exhaust with my old worn out engine and was getting oil in the stack after hard pulls, so when we built the new engine, I just ended up running 2 out of valve cover and one from front cover into a catch can with filter.

I like this setup much better. The way I see it, if it ever does puke on the track, at least it will go into a can instead of under the truck or on the track....
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I highly doubt that oil in the stack is from the evac, when rpm is up enough to pull vacuum on that venturi egt will be more than hot enough to burn any oil off instantly. If you have oil in your stack my first guess would be valve stem seals.
 
WUnderwood said:
zachu: where is the other breather going to? just curious
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It's going to a catch can behind the headlight.

Vincejax said:
I highly doubt that oil in the stack is from the evac, when rpm is up enough to pull vacuum on that venturi egt will be more than hot enough to burn any oil off instantly. If you have oil in your stack my first guess would be valve stem seals.
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I've got the same deal as him, only after a real hard pull I can see oil in my exhaust, sometimes I'll see a drip run down. The truck doesn't go through a ton of oil, just did valve stem seals less than a year ago.
 
Vincejax said:
I highly doubt that oil in the stack is from the evac, when rpm is up enough to pull vacuum on that venturi egt will be more than hot enough to burn any oil off instantly. If you have oil in your stack my first guess would be valve stem seals.
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It most definetly was.... when the rings are nice and worn at over 1100hp... It was coming from the crankcase. I never said it sprayed it out the stack, but you could see it and smell it after a hard pull.... I personally wouldn't recommend it in a competition vehicle or with a hood stack... a street truck with a full exhaust, maybe...
 
I have mine plumbed into the frt valve cover, with a good baffled pickup. Then a straight vent on cyl 5 cover going to a catch can.

My engine is plenty on the loose side, used to half fill the can, and have to zip tie a rag around the dipstick.
 
Mudn_1 said:
It most definetly was.... when the rings are nice and worn at over 1100hp... It was coming from the crankcase. I never said it sprayed it out the stack, but you could see it and smell it after a hard pull.... I personally wouldn't recommend it in a competition vehicle or with a hood stack... a street truck with a full exhaust, maybe...
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Can't be making much power if your egt is low enough to leave liquid oil in the stack after a hard run....
 
Having mine on the frt valve cover, and a good baffle mounted high, is the reason mine doesnt suck any oil.
 
jasonc said:
His truck hauls ass, dont go there. Runs 6.0 in the 8th.
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Fair enough then, I take it back about the power. I still suspect valve stem seals though. Oil burns off even at stock egt temps, so I'm having trouble understanding how there would be liquid oil in the stack after a hard run. My stack has only ever been bone dry.
 
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