Ok, here we go: So I got my new motor running this last weekend and everything starts out peachy. As of sunday night, I had my car up on a lift and no sign of fluid leakage anywhere. GREAT! So yesterday, after putting about 300 miles on the motor for break in, I decided it's time for some WOT. So I did 5-10 WOT runs, great oil pressure, great pull, everything is seeming very good.

I get home, start to take off my wideband equipment and notice a glaze of oil has splattered and blown all over the underside of the car. None of it was dripping or anything, just looked like what oil would if there was a trickle that was blown down under the car from vehicle speed. So I am thinking DAMMIT... So this morning I check my oil level, was topped off, no additional drips on the driveway, so I take off the intake since it seems the leak is coming from the back of the motor.

When I pull the intake off, I am amazed to see that all 8 head intake ports have oil stains where the intake manifold seals to them and that is where the oil is leaking from. The oil seems to be confined in the in b/w the intake head port and the manifold runner, minus that fact that a small amount is leaking by the O-ring seals. Now I know at over time oil will make it's way into the intake system but as for 300-350 miles and having a catch can on the PCV as well, this seems way too excessive. Also to note, the catch can is filling up much faster than it normally does.

Somehow oil is getting into the intake stream but I have no idea why or how. When i look into the TB opening of the intake, the floor of the intake has a glaze of oil on it, and when i look down the runner, the first 2-3 inches are oil soaked, but what is interesting is that the top of the intake runner does not appear to have contact with any oil. Looking down the head intake ports, the whole head port is oil soaked, the valve, etc. Not puddled or anything, just glazed over. And again, I think this is a bit excessive for a brand new motor. The oil was somehow leaking out b/w the O-ring seals of the Intake Manifold where it mates up with the heads and getting blown to the back of the motor and thus finding its way down around the bellhousing to the underside of the car.

Here's a few other things to note:

1) The MAP sensor had come unsealed and was not tightly located in its hold. Most likely causing a small vaccuum leak. Would this have any effect?

2) Everything was hooked up as it should be, trust me... did not break the oil pressure sensor. The oil is only coming from where I described above.

3) Could overfilling wth oil cause this? used about 1/4 a qt for the oil filter and then 5 3/4 qts for the engine (doesn't seem like this would make much a difference but i'm open to anything)

4) Valve seal break? Unlikely that all 8 intake valve seals broke but just coming up with ideas...

5) possibility of oil coming up through the piston rings? Again, unlikely with the intake stream moving everything into the combustion chamber...

6) PCV malfunction of some sort? I mean it obviously works since I am getting lots of oil in the catch can, but what is causing this excessive flow?

7) The 3 days I drove around for break in showed no leakage of anything, I stayed under 3500 rpms for most of that period, so it seems like this is related to WOT since yesterday was the first WOT sessions and yesterday was the first time I see oil leakge. BTW, oil pressure is as it should be.

Whew... ok thanks for actually reading all that, can anyone help troubleshoot here? Thanks

Will

 

Sounds like you have some ring blow-by. Maybe the rings have not fully seated yet.
I would call LME

 

Perhaps, but how would oil vapor make it's way to the vicinity of the TB? Unless he is running a cam with tremendous overlap that has unbelieveable reversion characteristics? I have seen weirder I guess.

This is not a turbo car is it? That's one way for excessive oil to get into the intake tract.

Lastly, did you dunk the intake in a parts washing tank before assembly? Maybe it's just leftover solvent coming out of the interior of the intake housing.

 

Pull a few spark plugs Wil....

See how oil soaked (or not) the plugs are. As another forum member has mentioned, it might be that the short block still hasn't sealed up yet which would be why some WOT runs caused additional blow by....thats when the cylinder pressure in the crankcase would be the highest. It does seem what your experiencing is excessive and Im still unclear on how it got outside the engine.

You might want to do a leak down test also....a new engine should have less than 5%.

Good luck,
Tony

 

If you are building some cylinder pressure under WOT, it can force oil vapor through the fresh air hose running from the pass side valve cover to the throttle body where there will be somewhat of a small vacuum signal at that point in the T/B. I don't see how oil being ingested through the intake is coating the bottom of the car though. Seems it would just get burned and go out the exhaust. If it is leaking so much between the intake and the head to coat the bottom of the car, you have some sealing issues with the intake manifold gaskets.

 

No the intake was dry, its an NA setup which is why I am very curious. Cam has nowhere near the reversion it would need to suck oil that far back up! However, I did find something else out. The knock sensor seals on the valley coverwere not seated, allowing a small passage for oil to exit the top of the motor. This is most likely another source of oil leakage, but it still wouldn't necessarily explain the excess oil in the manifold or in the head ports now would it?

 

Was just about to do that Tony, but then I found the valley cover issue. That, and the MAP sensor coming undone could explain alot of why it was so difficult to get the idle tuned up...

I agree with you, it seems ludicrous that with a properly seated intake, it could get outside the motor, but I saw what I saw, each intake head port had oil stains the shape of the intake manifold seal and small little trails leading down towards the valley. FAST manifold was tq to spec, sat nicely, and even with the valley not completely sealed the car still held decent idle. I may try running the engine with the PCV unhooked from the intake to see if I am really getting that much oil through. The only thing that doesn't make sense to me now is why there is so much oil on the floor of the intake, and the ends of the runners, but not the top of the runner....

 

find anything out?