What causes blow-by in a gas engine?

During combustion, high pressure on the top side of the piston pushes combustion gasses, as well as droplets of oil and fuel, past the piston rings and into the crankcase. This mixture is known as “blow-by.”

What causes excessive blow-by?

While excessive blow-by can be caused by pistons and rings that are simply worn-out or were improperly prepped during a prior rebuild, detonation, overheating or a lack of lubrication can be culprits as well, quickly destroying an otherwise perfectly good set of components.

What operating conditions cause maximum Blowby?

The most important source of blowby is the combustion chamber, Figure 1 [1774] . Most of the combustion blowby occurs when the combustion chamber pressure reaches a maximum, during the compression and the expansion strokes.

How do I know if my engine has too much blow-by?

However, one of the tell-tale signs of excessive blow-by is white smoke billowing from the oil-fill tube or opening on a valve cover. To check this, set the oil-filler cap upside down on the tube or opening. If it immediately blows off, there definitely is too much crankcase pressure.

What does blow-by at idle mean?

Engine blow-by is when there is a leakage of air-fuel mixture or of combustion gases between a piston and the cylinder wall into the crankcase of an automobile. Some signs of engine blow-by could be loud or sputtering noises coming from the engine, which could also be accompanied by clouds of exhaust or vented fumes.

How do you reduce engine blow-by?

Engine blowby can be reduced by following 2 steps : Step 1 Simply add FTC Decarbonizer in with the diesel . Step 2 Use Flushing Oil Concentrate when completing an oil change. “To fix engine blow by, FTC Decarbonizer is added to the diesel at each fill, and you literally just drive the engine clean!

How do you stop blowby in a gas engine?

How do you fix a blow by?

1. Clean Crankcase Ventilation. The first thing you need to do is check your crankcase ventilation to make sure it is clear of sludge and dirt.
2. Oil Treatment.
3. Replace Piston Rings.
4. Replace Pistons.
5. Replace Engine Block or Remanufacture Cylinders.
6. 9 thoughts on “What is Engine Blow-by?

What are crankcase emissions or blowby gases are?

The unwanted gases, called “blow-by”, are gases from the combustion chamber which have leaked past the piston rings. Early engines released these gases to the atmosphere simply by them leaking through the crankcase seals.

How do you stop Blowby in a gas engine?

Will seafoam help Blowby?

Seafoam: is good for OLD cars, who show signs of the intake needing cleaned, especially due to oil blow by. He recommends it BEFORE changing the upper intake manifolds on older cars simply because “It loosens crap up, makes it messy, but it helps because they can be cleaned just a smudge better.