What is blowby?

[Cliff_Johns]

When someone says that a diesel has excessive blowby, what exactly does that mean? Is it a generic term for a symptom which may have any of several causes? Is it a technical term that everyone whould agree on, or is it open to interpretation?

Thanks,
Cliff

 

[Cliff_Johns]

When someone says that a diesel has excessive blowby, what exactly does that mean? Is it a generic term for a symptom which may have any of several causes? Is it a technical term that everyone whould agree on, or is it open to interpretation?

Thanks,
Cliff

 

[Inspector507]

It usually refers to excessively worn piston rings thereby allowing air and fuel to "blow by" the rings into the crankcase.

 

[Inspector507]

It usually refers to excessively worn piston rings thereby allowing air and fuel to "blow by" the rings into the crankcase.

 

[KentT]

Blowby is compression from the combustion chamber(s) leaking into the lubrication system. It can be caused by other things (such as an ususal blown head gasket, hole in piston, etc.) but is typically caused worn or broken rings, as stated...

 

[KentT]

Blowby is compression from the combustion chamber(s) leaking into the lubrication system. It can be caused by other things (such as an ususal blown head gasket, hole in piston, etc.) but is typically caused worn or broken rings, as stated...

 

[bbse]

As stated it is compression being released from the internal part of the engine. But where you see blowby is usually from a tube off of the valve cover. It will run down the side of the engine and you will see a puff of air, smoke, oil on each piston compression stroke. Of course the tube could be missing. All engines can have some blowby. It is excessive to see oil misting, large amounts of smoke, strong air flow, you get the idea.

 

[bbse]

As stated it is compression being released from the internal part of the engine. But where you see blowby is usually from a tube off of the valve cover. It will run down the side of the engine and you will see a puff of air, smoke, oil on each piston compression stroke. Of course the tube could be missing. All engines can have some blowby. It is excessive to see oil misting, large amounts of smoke, strong air flow, you get the idea.

 

[PineRidge]

blowby = slang

Man did that dude blowby me in that corvette. /forums/images/graemlins/grin.gif

 

[PineRidge]

blowby = slang

Man did that dude blowby me in that corvette. /forums/images/graemlins/grin.gif

 

[Cliff_Johns]

Thanks everyone for describing it in a way that didn't blowby me. Makes sense.

Cliff

 

[Cliff_Johns]

Thanks everyone for describing it in a way that didn't blowby me. Makes sense.

Cliff