What causes excessive crankcase blow-by?
When you combine a large cylinder bore, high cylinder pressure through turbocharging, many hours of use and marginal maintenance, excessive blowby is the result. The leakage of any combustion gases, air, or pressure into the engine’s crankcase is considered blowby.
What does it mean when your crankcase breather is blowing oil?
If your crankcase breather is passing oil, chances are that something’s wrong (Okay, we know something’s wrong, but don’t be too alarmed). Here are some things to look for while you’re searching for the source of the issue:
What to do when oil comes out of valve cover breather?
You can expect lots of oil leaks and gasket failures. Make sure you have the PCV valve facing the correct direction. And, if that isn’t the problem, try a new valve. Your breather should act as the air “input”. If oil is coming out there, it is trying to act as the “output”.
What causes oil to blow out of the air filter?
Excess oil in the engine can cause the oil to foam and be blown out through the breather which generally feeds into the air filter.
How to avoid common causes of blow by and oil consumption?
Here are some common causes of blow-by and excessive oil consumption and how you can avoid them on your next engine build. The combustion process is never perfect. Even the best street engine never seals all that combustion pressure. A certain amount of cylinder pressure will always find its way into the oil pan.
If your crankcase breather is passing oil, chances are that something’s wrong (Okay, we know something’s wrong, but don’t be too alarmed). Here are some things to look for while you’re searching for the source of the issue:
Why does oil come out of valve cover breather?
This allows the low pressure inside the filter during high air demand to draw the vapors out of the crank. The sealed breather acts as a baffle and doesnt let oil up into the hose,the oil drains back into the cover.
Why does my street engine pull too much oil?
Either way, this is wasted effort. If your street engine tends to pull too much oil through the PCV valve or the valve cover breathers are constantly wet, check to ensure the valve covers are equipped with vapor separators like these. If the valve covers are not equipped with these separators, the PCV will pull way too much oil into the intake.
Here are some common causes of blow-by and excessive oil consumption and how you can avoid them on your next engine build. The combustion process is never perfect. Even the best street engine never seals all that combustion pressure. A certain amount of cylinder pressure will always find its way into the oil pan.