Oil Burn But Everything Looks Fine!

[lccynmbr13]

So I'm in my garage getting ready to pull my motor out for my rebuild due to losing a quart of oil every 150 miles or so today only to become completely stumped by what I find. I pulled the turbo off first just to make sure that wasn't the culprit (which I knew my 6 mo. old FP turbo was fine), no oil at all in the intercooler pipes, hot side of the turbo is dry as a bone. Next I pull the manifold off expecting to see wet exhausts ports... but they're DRY. Not a drop of oil on one of them, and all of the valves are dry as a bone too. I'm venting both of the breathers on the valve cover so I'm sure that's not the problem either. If the rings were bad wouldn't the exhaust ports be oily? I'm completely stumped here and now I don't want to pull the motor in case it's ok. Compression is between 175-190 across the cylinders on Wiseco 8.8:1s and I'm pretty sure the compression used to be between 190 and 205. 175 doesn't seem like low enough compression to burn that much oil to me. Like I said I'm totally stumped here any input would be highly appreciated.

 

[DSM4me44]

I wouldn't use breathers on both ports on your valve cover. There is no way you are relieving crankcase pressure fast enough by doing so. At most you should leave the PCV valve and line connected to your intake manifold.

Despite what you have said, my first thought would be that the excess amount of crankcase pressure, which you no doubtly have with that set up, has ruined your turbo seals.

I would check your o2 housing for signs of oil.

 

[lccynmbr13]

I said in my post that the turbo is completely dry. I don't have an o2 housing I'm on a t4 setup the downpipe is dry. Running the pcv valve and the crankcase breather open with tubes dumped to the ground as I have mine is the best way to keep pressure down on the short side of custom fabricating the valve cover to use larger AN fittings to a catch can.

 

[2point3Tsi]

I'm really curious too, I still have the 1 quart every 1000miles but I'm confident its the cold side turbo seals.

question. is there any smoke on deceleration? is the smoke loss only while driving i.e. no possible leaks on the underside? You have a no pcv just a hose running down right?

 

[DSM4me44]

I am still placing my bet on excess crankcase pressure damage on a seal.

You don't wanna take out your pcv valve, a lot of people do it, but it's not good. The pcv is there to vent out crankcase pressure, and without a vacuum line hooked into the intake manifold there will be nothing pulling out the pressure, just go to a mistu dealer and buy one for like $5, they're metal and last a lot longer than autozone's or wherever. - Habitatguy187

 

[MichaelSuch]

And you're positive you don't just have a major oil leak somewhere? Can you smell the oil burning when your driving the car?

 

[lccynmbr13]

2point3tsi yes I'm positive there is no external oil leak, i do have a pcv but it's been verified that it's in good condition, and yes it is dumping to the ground, well actually a gatorade bottle, now for the sole purpose of seeing if theres oil blowing out (which there isn't). I can definately smell oil when I come to a stop light but can't notice any significant smoke. It seems to be a freerev/boost/sometimes light accel deal. Hey is this Chris from Schucks?


DSM4me44 then please explain why almost every high horsepower car does not run a pcv valve? Not even just DSMs, most drill out and weld large bore AN fittings for maximum ventilation.

 

[2point3Tsi]

yes it is

has your oil consumption always been this high or did it develop over time? Also was your oil ring set looser for maybe nitrous?

 

[DSM4me44]

PCV valves allow for better crankcase ventilation then just running it to the ground.

Also, if you have it unhooked to the intake manifold, the PCV should remain closed at all times. Which means it would not be lettering anything out as of right now.

Before 1961, cars ran tubes to the ground to let vapors escape. The "closed" type PCV helps with ventilation a little better. Some people still run it the old way, and you will get some effect by doing so.

As far as why some peole still run it the other way? For the same reason some people still T their MBC off their bov line. It works for them and they see no reason to change. Another reason would be to eliminate an little bit of oil that would get sucked into the intake manifold.

 

[lccynmbr13]

PCV valves allow for better crankcase ventilation then just running it to the ground.

Also, if you have it unhooked to the intake manifold, the PCV should remain closed at all times. Which means it would not be lettering anything out as of right now.

Before 1961, cars ran tubes to the ground to let vapors escape. The "closed" type PCV helps with ventilation a little better. Some people still run it the old way, and you will get some effect by doing so.

As far as why some peole still run it the other way? For the same reason some people still T their MBC off their bov line. It works for them and they see no reason to change. Another reason would be to eliminate an little bit of oil that would get sucked into the intake manifold.

That's the most ridiculous thing I've ever heard a pcv valve is a 1 way valve. It's purpose is so that it opens when there is pressure in the crankcase but blocks off when the manifold is in positive pressure so it doesn't pressurize the case. If I have enough blowby that they case is seeing positive pressure the valve is opening up and venting the air out... The only possible thing better is a constantly open hole, or better yet, a LARGER constantly open hole.

Besides the point my turbo is fine and has nothing to do with the oil burn.

Chris no I haven't always burnt oil like this which is why I'm so bent about it. I just pulled the motor out tonight though and I'm gonna tear it down tomorrow so I'll know what the culprit is soon enough. I know the motor was built loose but not that loose. It was fine before I started running the T4 setup and was fine for a few months that way too.

I'm not too worried about it now though I'm going to use this as an opportunity to swap my H beams for some I beam rods and make it ready to max my turbo out this summer and hope to see a number in the mid 700hp range