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Blowby?

A

acontour

CEG'er
Joined
Dec 14, 2007
Messages
245
Hi guys
Can someone tell me what blowby really is?
I removed the oil cap and I do have air coming out. Is there supposed to be absolutely no air coming out?? I'm kind of confused.
Thanks
 
it is the leakage of gases from the combustion cylinder of an internal combustion engine between the piston and cylinder wall into the crankcase.

your motor is fine.
 
Even when they function optimally, piston rings do not provide a perfect seal. There will always be some gases getting past the rings. When the engine gets old and tired the rings wear or get stuck from carbon from poor oil change maintenance, you will have a lot more blow by.

The PCV (positive crankcase ventilation) system helps to control blow by. What you are seeing may be normal, or it may be an indication that your PCV system is restricted (usually a dirty PCV valve).
 
Thanks guys.
Can you remove all the blowby , by installing one of those PRT PCV oil separator kits? ( it's in Group by , PRT PCV oil separator kits).
Do you guys know if it will work on a zetec?:shrug:
 
Unless you have solid piston rings, which you don't and don't want, and a perect seal when the valves shut, then no, you can not completely eliminate blow by.

What Josh is selling won't have the effect you're looking for in regards to blow by.

It helps to seperate the oil that may get caught in crankcase vent tubes and from being redistributed to the incoming air charge for the cylinders. If you'll notice that some UIM/LIM are all gummy from deposits, it can be attributed to the recircualtion of exhaust gases (from the EGR) and PCV system
 
69Boss302 said:
Unless you have solid piston rings, which you don't and don't want, and a perect seal when the valves shut, then no, you can not completely eliminate blow by.

What Josh is selling won't have the effect you're looking for in regards to blow by.

It helps to seperate the oil that may get caught in crankcase vent tubes and from being redistributed to the incoming air charge for the cylinders. If you'll notice that some UIM/LIM are all gummy from deposits, it can be attributed to the recircualtion of exhaust gases (from the EGR) and PCV system
Click to expand...

Thanks for the answer. What's UIM/LIM? Sorry i'm not familiar with that.
 
acontour said:
Thanks for the answer. What's UIM/LIM? Sorry i'm not familiar with that.
Click to expand...
Somebody flunked newbe classroom! :laugh: Maybe we should have a "how internal combustion engines work" thread. :cool: Anyway, an engine is just an air pump. It sucks air in (intake) and blows it out (exhaust) and does some stuff in between those two steps to create power which in turn, moves the car. Generally the intake manifold is in negative pressure mode (vacuum) and the exhaust manifold is in positive pressure mode. The combustion chambers are in either mode depending on which stroke each piston is in. The only thing keeping those two worlds of air pressure apart when all the valves are closed in any given cylinder are the piston rings. If any pressure slips through from the positive (exhaust) side into the vacuum (intake) side, it is called blow-by mainly because it blows by the seals aka rings. Certain of the emissions devices recirculate this blow-by back into the intake side, most notably the PCV. Anyway, that's about as simplified as I can get describing how an engine works regarding its internal pressures. You may want to check out the How Things Work website or something similar for more information.
Karl
 
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