Do I need a PCV Valve and Breather?

Posted By: challenger70

Do I need a PCV Valve and Breather? - 06/02/10 09:02 PM

What exactly do each do and do I need a PCV Valve? Any Advantages to having a pcv valve? This would be for a 60's era 440. A rookie question I know but I never knew for sure.

Posted By: stumpy

Re: Do I need a PCV Valve and Breather? - 06/02/10 09:12 PM

The breather allows air in one side of the engine and the PCV pulls the fumes and pressure out of the crankcase and runs them back through the engine to be burnt. Without the breather you wouldn't have the necessary crossflow. Without the two of them working together you would build up pressure in the crankcase which results in oil getting blown out of all the seals. Using a breather in each valve cover will result in oil being blown out of them and all over the engine.

Posted By: challenger70

Re: Do I need a PCV Valve and Breather? - 06/02/10 09:40 PM

Cool, thanks for the great explanation, I wasn't sure if the PVC was related to some emmissions stuff I don't need.

Posted By: buildanother

Re: Do I need a PCV Valve and Breather? - 06/02/10 09:46 PM

The pcv DOES keep the oil aroma down while at stoplights, etc.

Posted By: HealthServices

Re: Do I need a PCV Valve and Breather? - 06/03/10 12:06 AM

Quote:

Cool, thanks for the great explanation, I wasn't sure if the PVC was related to some emmissions stuff I don't need.

It was one of the first and it was a good thing that we have them because before that there was only a draft tube.

Posted By: 68HemiB

Re: Do I need a PCV Valve and Breather? - 06/03/10 12:12 AM

Quote:

It was one of the first and it was a good thing that we have them because before that there was only a draft tube.

Yes. Good.

Positive Crankcase Ventilation is a much more complete way to remove water vapor and other undesirables*, when compared to a passive system.

*Disclaimer: Does not work well for removing visiting in-laws who have over-stayed their welcome.

Posted By: Scott Carl

Re: Do I need a PCV Valve and Breather? - 06/03/10 01:50 AM

Quote:

Quote:

Quote:

Cool, thanks for the great explanation, I wasn't sure if the PVC was related to some emmissions stuff I don't need.

It was one of the first and it was a good thing that we have them because before that there was only a draft tube.

Yes. Good.

Positive Crankcase Ventilation is a much more complete way to remove water vapor and other undesirables*, when compared to a passive system.

*Disclaimer: Does not work well for removing visiting in-laws who have over-stayed their welcome.

This really was a great innovation. The roads are actually clearer of oil, especially in the center. That was typically where the "draft" or "blow-by" dumped the gunk that pvc system collects.

Its still bad but in early years, the center of the road was the worst place for a motorcyclist to be when it started raining. Can you say, "Slip'n'Slide"??

Posted By: SomeCarGuy

Re: Do I need a PCV Valve and Breather? - 06/03/10 02:20 AM

Any advantage to having the PCV on one side or the other? I notice the factory changed sides around 70.

So I gather that the drivers side must have had an advantage.

Posted By: stumpy

Re: Do I need a PCV Valve and Breather? - 06/03/10 02:23 AM

Probably cheaper and more room. No a/c or heater hoses to deal with. There is no real reason to favor the driverside.

Posted By: ahy

Re: Do I need a PCV Valve and Breather? - 06/03/10 02:34 AM

The spinning crank will throw more oil on one side at high RPM. Its best to have the breather on the opposite side to reduce the possibility of sucking oil. I think this favors (slightly) putting the PCV on the pass side.