jeremy stanke

well a friend of mine who is a small time mechanic said that he thinks my motor has blow by. it is hardly even smoking. he had to take off the oil filler to see it, there is no smoke coming from the exhaust either. my question is this, if it really is blow by, how long will it last until the motor goes and how much power am i losing?

Injuneer

Blowby is the combustion products blowing past the rings and filling the crankcase. Up to a point, the PCV system removes those vapors, and they end up in the intake manifold where they are run through the combustion chamber again.

If you have excessive blowby, it isn't going to cause the exhaust to smoke. Its going to overload the PCV system, and the excess will flow out the passenger side valve cover, through the hose that connects it to the throttle body. Typically, you will see oil start to build up in the hose, in the top of the throttle body under the removable cover, and eventually soaking the intake with oil starting at the throttle body.

Check all those locations for oil buildup. Pull the oil fill cap off (engine running) and look for smoke coming out of the fill tube. In severe cases you can feel a "puffing" out the oil fill tube, or even hear it.

twcblackhand6970

not to thread jack, but I have some smoke coming out of my oil filler hole when I take the cap off, is it normal to have some smoke? and my pvc hose has some oil in it, but not enough to flood the intake and come out the tb. So is that excessive or normal?

twcblackhand6970

? Anyone

SS RRR

I assume your PCV system is still on the vehicle? If you're seeing smoke or can feel positive pressure coming out of your oil fill hole then, as Fred said your PCV system may be overloaded. Check your PCV valve to make sure it is not clogged. The breather tube that connects from the pass. side valve cover to the TB is neutral flowing. When an engine is not seeing vacuum (ie under acceleration) blow-by is then channeled through this hose and it is quite possible oil can make its way into the plenum. This has been a common problem for LT1's which do not experience excessive blow-by. Every engine generates blow-by. The best way to know if you are truly experiencing excessive blow-by is to have a leakdown test done on each cylinder.

twcblackhand6970

so how do i check to see if my PVC system is overloaded? I don't really feel any pressure, but I can see minor buffs.

Injuneer

Now that you have highjacked the thread , have you checked the operation of your PCV valve?

twcblackhand6970

i wasn't expecting to keep going, but no, I don't know how to check operation of the valve.