Engine Valve Cover Vent Hose Necessary?

[dstang01]

Hey folks, doing a head swap and my new valve covers don't have a fill neck with a nipple for the vent hose. Should I look for a cap with a hose or would I be fine deleting it? Doesn't the PCV take care of venting?

 

[revhead347]

The PCV valve is where it goes out of the crank case, you need a vent for fresh air to come in. It doesn't have to be a hose, you can use a breather cap.

Kurt

 

[dstang01]

Thanks, I picked up something like this from the parts store and it should work!

 

[revhead347]

Does that have a breather element in it, or is it just a baffle? If there is no breather filter inside of it, that nipple has to be connected with a hose back to the intake.

Kurt

 

[HISSIN50]

You might also want to take metered air into consideration if you don't keep the system closed..........

 

[revhead347]

You might also want to take metered air into consideration if you don't keep the system closed..........

I know this is a technicality that is a correct consideration, but in all honesty I've never seen it be enough air to make any difference.

Kurt

 

[dstang01]

It's baffled and I ran 1/2" heater hose from it to the nipple on the intake, still a closed system. It actually looks great with classic chrome valve covers

 

[toyman]

I know this is a technicality that is a correct consideration, but in all honesty I've never seen it be enough air to make any difference.

Kurt

Really. That's like a big vacuum leak. I wouldn't be surprised if many surging idle issues are caused by adding unmetered air into the equation.

 

[revhead347]

Really. That's like a big vacuum leak. I wouldn't be surprised if many surging idle issues are caused by adding unmetered air into the equation.

I would tend to agree with you given the size of the hole in the PCV valve, but I've never seen it make a difference.

Kurt

 

[k00ksta]

un-metered air is always bad business from what I have seen. But maybe its not enough to cause issues.