I had a interesting evening yeaterday. I was driving My TA & I got on the throttle pretty hard for a few seconds, & when i let off I noticed a ton of smoke in the rear view and when i stopped it looked like someone threw a smoke bomb under the front of my car. I pulled over and lifted the hood. The dipstick was out of the tube a couple inches and of course oil was everywhere and it was on fire and burned up 3 plug wires and the starter wires. I have a breather helping with crankcase pressure, and when i went to check the PCV valve, Its not really a valve, Its just a plastic elbow attached to a hose which goes to the rubber sleeve that attaches to the front of My throttle body, and for some reason my dipstick does not fit snug at all in tube. I do not think i have a ring problem as the car never smokes even while i drove it home, it just mised a little which im sure is from the plusg wires. I guess my question is What would be better, A normal pcv valve or a plastic elbow.

 

You should already have a "normal" PCV valve The stock PCV valve is a regular spring-loaded valve, that pushes into a grommet on the driver's side of the intake manifold. On the 93/94 engines, the vacuum source is a vacuum nipple a few inches behind the PCV valve, on the same side of the manifold. On the 95-97 engines, the vacuum source is a line that runs from the PCV valve to a port on the front of the intake manifold, under the throttle body.

The hose on the passenger side should run from a large nipple on the upper/passenger side of the throttle body, to a plastic elbow located toward the rear of the passenger side valve cover. That line supplies filtered, MAF metered air from in front of the TB blades to the passenger valve cover, so the vacuum from the PCV valve can pull the clean air through the crankcase and lifter valley, picking up the harmful blowby vapors. If you overpressure the crankcase with excessive blowby, the flow in the line on the passenger side valve cover will reverse, and the excess pressure will be relieved to the throttle body, and the vapor burned in the engine.

There is no breather in the stock system, and by adding a breather, you have opened up what is designed as a closed system.... no big deal. There is also no connection from the PCV system described above to the rubber inlet bellows on the throttle body, if that is what you mean by "the rubber sleeve that attaches to the front of My throttle body".

If your breather, the stock PCV valve and the vent line on the passenger side valve cover couldn't handle the crankcase vapor load, there's a good chance you lost a ring land.

 

I gotcha, This engine has around 1500 miles on it, & this is the first time ive had any kind of issue. If there was to much crankcase pressure wouldnt it have been a problem before. And if there is a ring land problem, im assuming the car will smoke once i get the wiring redone. I already replaced the pcv valve. When i took it out it still made a little noise when i shook it but it didnt sound like the new one. I Should tell im also running a ati procharger. In your opinion if the dipstick did come out of the tube a few inches and you got on the motor a little with a supercharger is it feasible that it could push oil out the tube that much.

 

You most likely have hurt a piston, Mine did that and I had 2 hurt pistons normally apsirated. If you only got on it "a little" You got a problem.

Have a leakdown test done on it.


David

 

Sounds fammiliar to me.
I did have almost the same problem a while ago when i was playing with a porsche on the autobahn(dipstick out and oil everywhere).after that action the crankcase pressure was everytime a litle more higher after a few WOT runs.
Finally the pressure was so high it popped of a hose or the oildipstick everytime.
Right now a have 5 pistons lying on the table with broken ringlands.
btw. still no smoke from the rear when i put it in the garage.
Have a leakdown test done on it,that is the most easiest part to start with.

 

You should have told us up front. I basiclly wasted a lot of time telling you how the stock PCV system functions. Boosted engines have unique issues with the PCV system - if I knew it had a blower, I would have addressed that part.

You really need to use the "signature" field to let people know the basics about your car. Not letting us know its a boosted motor really hurt your chances of getting an accurate answer.

 

A buddy of mine just replaced the motor on his '97 SS with a 396, and in the process of stripping down the original motor, found 3 broken ring lands. The car had a supercharger when he bought it with low miles, and we took it off after a few months (obviously too late though). It ran fine before being pulled, and did not smoke at all out of the tail pipes. It did have a problem keeping the oil dip stick in the tube and would pop out all the time.

I would say you definitely have one or more broken ring lands, without a doubt.

Is the bottom end stock? As Injuneer stated, a signature would definitely be in your best interest, so people can see what you have.

Thomas.

 

Just because there is blow-by, you can't presume the motor has a broken ringland, especially when it involves a motor that's using a forced induction system.That's like a doctor telling his patient he is dying because he has a headache. Is it possible...YES, but further tests need to be performed. It may be nothing. As Fred mentioned, boosted engines have to deal with positive crankcase ventilation in a different manner (at least when the intake tract goes from a vacuum to pressure when in boost). In a normal LT-1 PCV system, when pressure is applied to the intake along with some additional blow-by due to elevated cylinder pressure from boost, all on a motor that only has 1500 miles on it, its no wonder oil was being pushed out the breather that was added, especially if there isn't any baffling under the breather.

Research the options for properly venting the crankcase with a boosted motor, make the necessary changes and do a cylinder leakdown test and possibly a compression test (based on the results of the leakdown test) and then you can decide what if anything needs to be fixed.

As also mentioned above, add a "signature" with details so people know what you are driving.

 

Thanks for all the responses. The car is getting a compression test & leakdown test Tomorrow, so well find out then. After that if everythings ok, ill research the proper venting for this combination, & i will add a signature so people know what im dealing with.

 

Well i had the motor checked today with a leakdown test. Every cylinder fell between 7 & 9 Percent. The compression check was 180 high and the lowest was 171. So im thinking everything in the motor is okay. I looked at the Procharger manual today just to make sure, and there instructions to vent the crankcase are just the way i have it. Ive searched on here and there seem to be alot of different ways to evac the crankcase, So for a forced induction motor was is the best.

 

I have since posted a signature so it will help people from now on.

 

I would have to agree that based on the results of the leakdown and compression tests, there isn't anything obviously wrong with the motor. Do you happen to know if the motor was cold when the tests were done or was it close to operating temp???

Unfortunately, the immediate speculation that goes on from time to time usually doesn't help anyone out.

Regarding the excess crankcase pressure you're experiencing, check the Forced Induction section if you haven't already. There are several posts dealing with this situation. It's really a matter of choice as to how you properly vent the crankcase of a F.I. motor.

Lastly, you didn't mention how much boost your motor is seeing and if you have had it tuned, but with a stock LT-1 motor, these are two very important considerations. As I'm sure you already know,, the stock LT-1 is not a boost friendly motor.

 

I did search on the Forced induction board, and saw several methods. I just have decide which one is best, Im geting right around 10psi of boost, and this isnt a stock motor, thats why i was baffled at talk of a broken ringland, but i know the more power you have, the potential for more issues. I appreciate your info Boosted_Z28. Now that i have the car back its time to get under & start cleaning.

 

Glad to help out. Hope you get it resolved and the evac system works better for you. Post your progress with the car and how everything is working once you get it back on the road. Good Luck!!!