PCV VALVE

[70 StangMan]

Do you have to run the PCV hose from the left valve cover into the carb. or can you just use 1 vented breather cap on each valve cover if your carb. is not set up for the hose ??

 

[Anonymous]

I don't run any PCV. I run both sides down to the headers, runs just fine. I used to have a vented cap on both covers, but it let the underside of the hood get oily. I don't remember if street driving did it, but WFO at the track sure did.

 

[70 StangMan]

Thank's Mark...my new carb. doesn't have the inlet for the PCV and was hoping I could just get another breather cap and move on. :steer

 

[lethal289]

Thank's Mark...my new carb. doesn't have the inlet for the PCV and was hoping I could just get another breather cap and move on. :steer

Thats what im doing, but i've been read the riot act on here for not having a PCV. Something about prolonged engine life IIRC.

 

[Starfury]

On a street car, you really do need a working PCV setup. It clears corrosive gases out of the crankcase. Left unchecked, they can cause a nasty, sludgy, corrosive buildup in your crankcase. There really is no downside to running a pcv setup on most vehicles.

High performance/track cars present a different problem. PCV setups don't work at WOT, which is where track cars spend a significant amount of time. However, those same track cars get their oil changed much more frequently, which helps keep things clean.

 

[apollard]

Many boats used to not run PCV. However, the manufacturers switched to PCV systems well before they were mandated to eliminate customer complaints about oily residue in the bilge and oil smells after cruising around. The mechanical benefit was cleaner oil and extended scheduled change intervals ( a nice cost savings, changing my boat requires 10 qts of synthetic).

I ran in to the odor / oil residue problem on my boat (built just before the changeover in the 90s). I retrofitted a PCV and it took care of the odor issue, and the bilge & engine stays cleaner outside (no more cleaning to keep her shiny). The oil analysis improved significantly - at 20 hours, my oil used to have ~1% fuel contamination and no additives left (TBN<1). Now, at 40 hours, no fuel present and TBN barely changes from new. Saves me over $100 each season.

I'm sold.

BTW, a $15 carb spacer from summit was my solution, since the boat had no other provision.

 

[blue65coupe]

I'm with Tad. It doesn't have to be run out of a particular side to the carb but more important is the ventilation. You can get a breather cap that is filtered and not set up for the valve/hose.

 

[Mach1Rider]

Do you have to run the PCV hose from the left valve cover into the carb. or can you just use 1 vented breather cap on each valve cover if your carb. is not set up for the hose ??

Yes you can place a vented breather cap on both Vc's, But now your not drawing air out just venting.
The only time it will draw is when it is moving air across the vented caps.
Drawback is now its a vac that will pull oil out your caps and make a mess.

I am using vented caps on both Vc's but have tapped the intake at the valley with a port and tubed up to the air cleaner inside the filter.
This is drawing air in thru the caps and out of the crankcase.

 

[cmayna]

Im running a PVC valve from passenger valve cover to back of the Holley. Then a non vented valve cover cap with a port on the drivers side which heads over to the air cleaner base.

 

[Horseplay]

I am using vented caps on both Vc's but have tapped the intake at the valley with a port and tubed up to the air cleaner inside the filter.
This is drawing air in thru the caps and out of the crankcase.

I am really liking this idea. I have never liked having not just a PCV set-up on a VC but ANYTHING on them. This would seem a way to eliminate anything altogether which is the look I want.

 

[Mach1Rider]

This is how it was set up to start with, using a pvc valve to the carb base.
After the first run it was changed by removing the pvc valve to a straight tube from the intakes valley to the aircleaner base plate.
Seems that there was WAY too much draw even with the valve in and sucked oil. :no
Now even after some hard runs over 6K it does not suck oil and ventalates the crank case just fine.

 

[classicdoug]

So this thread made me go out and look at my car I'm building. I have a set of Ford Racing valve covers that came on my crate engine from Ford. One cover has an oil filler tube with a nipple sticking out of it. The other valve cover doesn't have any holes drilled in it.

Am I correct in thinking I should drill a hole in the solid cover, install PCV valve, and then run a hose from it to the base of the carb, and then use the existing nipple in the other valve cover to run a hose to inside the air cleaner?

Thanks,
Doug

 

[Mach1Rider]

Doug, Yes you need some sort of crankcase ventalation or it will be when not if you start blowing out gaskets and such.

You planned thinking is a clean air system and will work well.

 

[Starfury]

Mach: so you run no PCV valve in that tube?

I'm still trying to figure out how to prevent my PCV system from sucking oil out of the crankcase. I spin my motor up to 6k regularly and have issues with oil getting drawn into the intake.

 

[TB350]

Looks like a pcv valve between the red stub hose and the black one to me. Neat set up! kip

 

[Mach1Rider]

Mach: so you run no PCV valve in that tube?

I'm still trying to figure out how to prevent my PCV system from sucking oil out of the crankcase. I spin my motor up to 6k regularly and have issues with oil getting drawn into the intake.

Correct, there is now NO pvc valve installed and the port of the spacer plate is plugged.
Its now using a straight tube from the intake valley to the air cleaners base plate.
The air crossing over the open tube going to the carb creats a vac draw to vent crankcase, works like the old downdraft tube.
It doesn't suck hard enough to draw oil up and out.

 

[Starfury]

Interesting. I'll have to see if I can make that work with my 331...