Technical pcv valve? or not

is it necessary to put a pcv valve in my 350 chevy on the 26 raodster.. or can i use a simple vent.. it looks bad on a hot rod.. but if its necessary ill put it on.. thanx guys

 

I used a road draft tube out the back, out of sight. Tim

 

This has been bantered about on here many times in the past. The good, the bad, the wrong and the right, even threads about how to hide a pcv. Do a quick search, there's a lot of info.

 

no, you don't need one. Especially if you don't put a lot of miles on the car. Expect some wisps of smoke out of the vent occasionally.

 

They are not a must,but I prefer to use one. HRP

 

The crankcase definitely needs to be vented. A properly designed vent system with a road draft tube will work. A properly designed PCV system will work better.

 

Crank cases have to breath and they breath a lot more than most people realize which means you pull a lot of dirt (abrasive) into the engine. PCV, road tube, vented oil fill caps. Whatever method you use, try to set them up with some sort of filtration.

 

the positive crank case ventilation has an important job. it pulls hydrocarbons out of the crank case and also by putting the crank case in a vacuum it helps with piston ring seal. that's why you see big dollar vacuum pump set ups on race cars. better ring seal, better running engine.

 

Less sludging....

 

What George said!

The crankcase can see a surprising amount of moisture from condensation and humidity from the air that passes thru it. It's especially a problem for engines that are "short hauled" a lot and don't spend much time running at full operating temperature. As engine temps rise the moisture vaporizes and the PCV system pulls the vapor from the crankcase.

 

Simple answer, yes it is necessary for a clean engine AND less pollution...

 

Putting the crankcase in a vacuum by adding a PCV means that oil is less likely to seep past your seals and gaskets. Also as others have said - less sludge buildup.

I am sure you grasp the challenge of trying to achieve a period-correct look and the benefits stated above

Posted using the Full Custom H.A.M.B. App!

 

PCV won't put vacuum in the crankcase unless you restrict the intake of out side air [mad mikey diagram] from interring the crankcase..

 

I fully understand the PCV system. But i don't like it. Sure you get less sludge in the engine but at the expense of gunking up the intake, valves, and carb. I tried and tried to get a PCV to work on my model a to no avail. I think the open engine bay combined with the zips riser and the front fill intake caused problems. So i just added some breathers to the valve covers and got rid of the PCV.

 

The yes people are right for all the right reasons.

 

Yes, on every engine.

 

Without PCV your car interior is gonna smell like a crankcase while you're driving. That alone was enough to make me do a PCV conversion.

 

No offense intended here but a rod draft tube is going to be pretty hard to set up on a 350 chevy, the block doesn't have provisions for one.

You can avoid both the PCV and the road draft tube if you set it up with a vacuum pump, and properly set up a vac pump looks total performance. looks are what we are after here correct?

 

You can disguise a PCV if you don't like the looks. A properly baffeled and filtered pcv works very well.

 

Yes, you need to have "Crankcase Ventilation"-no, you do not have to run a PCV-I am not from the Camp that proposes the use of a PCV-
1. It introduces Oil back into the Combustion process, therefore detonation can occur at a lower threshold
2. It will allow for increasing Oil deposits on the Intake Valves-

PCV Valves were one of the first Emissions controls-if your Car isn't governed by Emissions you don't have to run one-
I am running dual Breather Tanks (that have K & N filters) on my Car-properly engineered, they do the job quite well without the need of the downsides of a PCV valve-

 

Would you explain your dual breather tanks or supply a diagram?

 

Sure,

I don't have pictures of my Car (before & after), but here are some of my friend's car (who has done the same thing)-look at the Valve Covers, and you can certainly hide them-

This subject seems to be a great mystery to many (myself included) until I did my homework-

 

Usually breather tanks are done in conjunction with a vac pump or some other type of evacuation process.

 

The problem (on a street car) is that a crank-driven Vacuum Pump won't live very long (needing to be rebuilt, they were designed for Racing), and the electric ones (like on a '03-'04 Cobra) don't have enough CFM to keep up, so, unless you are running low-tension rings (and HAVE to run a Pump) this works very well-

 

We actually use the emissions pump from a ford on our boosted cars. They hold together real well and are cheap at the wrecking yard.

 

What carburation are you running and how do you propose metering it with no PCV system hooked to its correct fitting? You cant just put a bung on it. JW

 

Why not? In my case, I am running a Hilborn-as a matter of fact, Hilborn recommends that you don't run a PCV:
"Open vacuum accessories including PCV valves are not recommended as they will reduce or eliminate resolution for the MAP sensor."

http://www.hilborninjection.com/tech_elect_faq_ECUs.asp

 

You answered your own question JW

 

Huh? If I wanted to run a PCV, there are ways to get around putting it back through the MAF-I am not running a PCV for the above reasons-