Lots of oil from oil breather on new rebuild ???

KWIKR 1

Active Member
Joined
May 25, 2001
I have a new rebuild with about 550km . I've been boosting the engine a bit (10-12psi) and I have been getting alot of oil out of the DS K&N oil breather . enough to drip on the wire loom plastic . Is this normal on a new rebuild ? should the rings be some what seated by now ? Thanks.
 
what kind of rubber gasket does the breather have? if it has a "split" with overlap, under boost these will seal, pressurize the block and blow oil

just trim the gasket so the flaps don't seal
 
It's a ATR DS billet piece with a K&N on top . I took a closer look at the K&N filter and it looks like it may have to be replaced .The 1 1/4 " black rubber piece end that goes into the billet part looks worn . It's only about 2 seasons old . I'll give that a try and see what happens .thanks.
 
I sealed up K&N breather and I'm still having a problem when I'm boosting the car . Should I have this much oil coming out of the DS breather on a new rebuild ?
 
hmmm...oil coming out the breather means pressure in the crankcase.....you are sure the path out the breather is clear, nothing blocking it? is your pcv valve working properly? (ie not letting boost in) any oil on the pass side?
 
I do not want to sound like the grim reaper, but if your crankcase breathers are "breathing" and the pcv valve is working properly, you need to look a little farther.....like into your oil and radiator....any evidence of water/oil.....could be a leaky intake, could be a gasket (head type) or???......but oil should not be getting pushed out of your engine unless some pressure is getting into your crankcase

are you sure the breathers are open? does the Kirban breather use a gasket that goes into the valve cover? (or does it just sit on top?)
 
My 86 had the same problem. But it was about time for an oil change and ever since i changed the oil, it never leaked from the DS breather. But i hadn't had it leak from the passenger side too.
But i hope you find the problem.

Scott
 
Do a compression test - you may be surprised. I had 90psi in all holes (rings never seated) and it blew oil out the breather.
 
The DS breather rubber gasket just sits on top of the valve covers . The PS is a stock type rubber split gasket. I pulled the PCV valve and blew in the one end . It seems to be passing a little air , so I swaped it for another . I'll have to take it out tomorrow and see if it improves . What would cause the rings not to seat on a new rebuild ?
 
Tim
I would pull out that check valve that you have hooked up in the PCV line and see if that makes a difference.

Paul
 
Paul check valve is not in yet . I bought it to see if it would help my problem but I haven't installed it yet .
 
Well I think I may have a solution to my problem . I tried the ATR Check valve in line with the PCV Valve and notice a change in idle quality (the valve seemed very restrictive) . So i decided to try a little trick . I put 2 GM PCV valves in line of one another . I figured any boost that the first could not hold would be picked up by the second one inline . I then took her out for a few good boosted WOT blasts . To make a long story short when I came back I checked under the hood . To my amazement there was a oil drop the size of a pin head on the wiring loom (most likely left over before the change). Not like the big drips I was getting before with just one new GM PCV valve installed . So , if any of you guys are having similar problems I suggest you give this a try . It's a cheap fix and may work for you . Take care.....Tim.
 
glad it was something simple...you can take the pcv valve out of the equation if you want....just block it off (get an old one and plug it up)

no ill effects if your crank is breathing properly

put it back in for smog test
 
Hey Tim,

Glad to hear the problem wasn't something big. That would totally SUCK.

Back in spring of 1999 I spent a ton of money having someone do a total rebuild to the engine in my Limited only to have to pull it back out... :mad: Needless to say I never let that "someone" near my car after their first botch job, and I attempted the second rebuild myself. [and it worked too LOL]

Good luck with her! :)
 
Steve , I remember you telling me your rebuild horror story by email about being 30 mins town the hwy with your new engine and throwing the thrust bearing out . And then just getting the total F around from the builder (we will not mention "someones" name :D). Talk about a total bum out .

azgn,So there is no down side what so ever to block off PCV valve ? I notice with my problem the oil would get dirty very quickly . was that from the crank case blowby?
 
no downside........(well, unless you are the EPA, because all those nasty gasses will now go into the air instead of the TB)

plug it up and see what happens.....if you still have pressure into the crankcase, you may need to look further

good luck
 
Me too Tim!

Tim, I had the same problem with mine for about 500 KM's. I went through 7 PCV valves before I got a good one. I finally bought the ATR check valve and now all is fine. Do a "suction" test on the PCV valve right at the store to verify if you have a good one. This works, I just have the wife do the test on them.....just kidding. Glad to see that Roger builds a constant motor.
 
Yep....

Tim, I am sorry that I did not clarify. I run only the check valve from ATR, no PCV in-line. It works great for me. Yours should run the same as mine.
 
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