PCV filter change question

[66corsaguy]

I’ve got a filter on my PCV tube. How often should i change it? I have a decent amount of blowby. If i wrap my hand around the filter it leaves oil on my hand.

Are they washable or must i buy new?

Image1546631207.331941.jpg (110.45 KiB) Viewed 522 times

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[66vairguy]

Most folks don't realize dumping the blow-by out the PCV tube, even with a filter, into the engine compartment lets carbon monoxide get pulled into the cooling system. IF the heater is on then it goes into the car - not safe.

There are aftermarket air cleaners that accommodate the PCV plumbing like the stock air cleaner does.

[66corsaguy]

Most folks don't realize dumping the blow-by out the PCV tube, even with a filter, into the engine compartment lets carbon monoxide get pulled into the cooling system. IF the heater is on then it goes into the car - not safe.

There are aftermarket air cleaners that accommodate the PCV plumbing like the stock air cleaner does.

So no answer to the actual question tho?


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[bbodie52]

Crankcase ventilation systems are designed to control the balance of air pressure between the engine crankcase and atmospheric pressure while processing the accompanying fumes. The overall volume of blow-by varies due to cylinder pressure, piston ring pressure and component wear.

Venting the emissions to the atmosphere is a simple solution to release the pressure and trapped fumes. This was done on Corvair engines from 1960 - 1962, using a Road Draft Tube. With the road draft tube, the open end faces down and is located in the vehicle's slipstream. When the vehicle is moving, airflow across the open end of the tube creates a draft that pulls gases out of the crankcase. It does not function when the vehicle is moving too slowly to create a draft. Systems using the road draft tube had a tendency to have increased contamination build up in the crankcase because of the relatively poor, inconsistent operation of the road draft tube system. Frequent oil changes were needed to reduce contamination build up in the crankcase and valve train areas, called ENGINE SLUDGE. Sludge is a gel-like fluid that can seriously damage your engine. Thousands of vehicles using this system also contaminated the atmosphere, causing increased problems with SMOG contamination.

Sludge Contamination

From 1963-1969, Corvair crankcase fumes were managed by an ingestive system, which vents the blow-by back into the engine, where it returns to the combustion process. The ingestive crankcase ventilation system routes any crankcase emissions into the intake air stream, where it is re-burned in the combustion process. This system is known as Positive Crankcase Ventilation (PCV). Fumes are drawn back through the intake system into the combustion chambers via two paths. One path is via a PCV valve or a fixed metered orifice into the vacuum balance tube and then directly into the intake manifolds. At some engine speeds and throttle position settings the engine vacuum is low, so a secondary path is needed that vents the fumes into the intake system via the air cleaner housing and then through the carburetor intake, instead of a direct path to the intake manifold.

DISCONNECTING THE PCV SYSTEM FROM THE AIR CLEANER HOUSING IS OFTEN DONE WHEN INSTALLING CUSTOM AIR CLEANERS ON THE CORVAIR. OWNERS OFTEN SUBSTITUTE A SMALL FILTER ATTACHED TO THE END OF THE PCV TUBE, AS SHOWN IN THE PICTURE AT THE TOP OF THIS ARTICLE. THIS IS AN INADEQUATE MODIFICATION THAT CAUSES SOME CRANKCASE FUMES TO BE VENTED INTO THE ENGINE COMPARTMENT, WHERE THEY CAN BE DRAWN INTO THE COOLING SYSTEM BY THE ENGINE FAN. The fumes can then enter the passenger compartment via the heater and defroster!

The correct way is to purchase or fabricate a PCV system air cleaner adaptor, like the one shown below. The PCV tube should then be reattached to the custom air cleaner to vent the system back through the carburetor. It is not necessary to attach the PCV system to air cleaners on both sides of the engine. Re-connection of the PCV system to an air cleaner housing on either side is sufficient, and will prevent fumes from entering the engine cooling air path.

https://www.summitracing.com/parts/mrg- ... gKpP_D_BwE

Crankcase emissions result from combustion byproducts and/or exhaust fumes escaping around the piston rings and into the crankcase. These escaping fumes are commonly called blow-by. If not controlled, the blow-by can contaminate the lubricating oil and pressurize the crankcase, possibly leading to an oil leak.

Elements found in blow-by can include wear particles, oil, fuel, gas and air. The specific composition of the elements varies due to fuel type, engine type, engine speed, load and maintenance history. Typically, blow-by is made up of hydrocarbons (HC), carbon monoxide (CO), carbon dioxide (CO2), nitrogen oxides (NOX), water vapor and traces of sulfates and aldehydes. Crankcase hydrocarbon emissions are normally 3% of the total exhaust emissions tested at the mid-life of the engines. However, due to piston ring tolerances, crankcase hydrocarbon emissions can increase to 20% of the total hydrocarbon emissions.

[nmunn]

Thanks for the link to the adaptor, was wonder how I would best tie back into my aftermarket air cleaner.


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[joelsplace]

If the filter is a K&N type filter it is washable.

[66corsaguy]

Thanks.