Is the PCV valve and related components REALLY necessary?

[MrSony]

Title says it all. I've seen tons of older engines run without it that came with it stock and they've held up fine. I'm not against it, but it's just less #@&! I have to hook up to my shiny new Buick 350. the Buick has the two buldges on the passenger valve cover, and a hole for a breather/pcv and oil fill on the driver's side. Do I need it?

 

[pontiacgp]

yes you need it, there is pressure built up in the valve covers that needs to be vented.

 

[GuysMonteSS]

yes you need it, there is pressure built up in the valve covers that needs to be vented.

X2 !!!
Guy

 

[Rktpwrd]

I agree with Steve and Guy, you need to have some way of venting off the crankcase pressure and gases or else you can start to blow out gaskets with the unrelieved pressure.

However, if you're dead set on removing the PCV system, you need to replace it with something else.
In the case of my BBO, I installed a "pan evac" system that uses exhaust pulses to create a vacuum of sorts to draw the gasses out. It dumps them directly into the exhaust stream bypassing the need to reburn them through the carburetor. This system is shown with the included breathers in the valve covers below.
NOTE: This modification is rated as "off highway use only" and will not pass emissions testing if required in your area.
Just an option for you to consider.

 

[HAFROD]

Old engines your referring to have a road draft tube. On older SBC's they go back behind the intake and are barely noticeable. I've seen guys put push in breathers on but they always seem to drip oil out onto the valve covers. A good hard pass at the track and a little gets on the exhaust

 

[565bbchevy]

I agree with everyone above and once you build your engine big enough to where the header evacuation system no longer does a good enough job you then go with a belt driven vacuum pump and set it up so you can adjust how much vacuum it pulls relieving crankcase pressure and creating more power in the process.

 

[MrSony]

Ok, thanks for the info guys!

 

[Judge Mills]

So, besides leaking oil, what would be the benefits/disadvantages of going dual push-in breathers? My 81' came with a tube from the passenger side valve cover to the air cleaner, and a PCV on the driver's side that also goes to the charcoal canister.

Since I don't have the stock air cleaner, I removed the tube and put in a push-in breather. I have no problem keeping the PCV in my vehicle, but it goes to the engine AND the charcoal canister. Is there a way to bypass the canister, or is that not advisable? This car does not need to keep its emissions equipment, and is actually missing a great portion of it. Eventually a 350 will replace the 305. Sorry to hijack the thread, but this is good info

 

[MrSony]

^Also wondering.

 

[MrSony]

Also, since only one valve cover for the Buick 350 has a hole for a breather, does it matter what side it goes on? Or would I have to source another valve cover with a hole for the other side?