bye bye pcv any negatives to it???

[eljefino]

Even if you don't want a PCV put in a road draft tube so there's fresh air moving through and across the rocker area.

Tampering with emissions gear on a past-mid-60s car is a violation of federal law, even if your car passes state inspection.

 

[USA1]

This is a great example of an owner-operator insisting on being smarter than the engineers of their vehicle. No engine can seal the pistons 100%; blow by will always occur. Without a relief of blow by, the weakest seal or gasket will become a vent, and leak oil. Used to be you could tell a stuck closed PCV vqalve by the valve covers leaking like mad. It's not a question of if, but when and how bad the leaks will happen. If just the intake opening is being closed, then the vacuum source will draw in atmospheric air through a gasket or seal, and may still leak. Just leave it the heck alone!

 

[Drew2000]

Geeez, Car Mfgs. have been using positive crankcase ventilation for what? like 45 years. I think they pretty well mastered the technology. Leave the PCV system operational.

 

[Ausfahrt]

Originally Posted By: sunfire
You'd probably end up with a lot of sludge in your engine. Good thing PU will clean it all up for you.

 

[EvanD]

They will have a nice K an N breather on each valve cover. I already have a huge K and N filter on a custom intake. Yes it adds power when you start making other changes in the tune open exhaust upped timing and everything else.

This is no longer a stock vehicle.

I think you guys misunderstood the blocked opening is on the intake manifold not the valve covers.

 

[jcwit]

K & N? Isn't that the outfit that claims their air filters last 100,000 miles? OOOOOOOK

 

[EvanD]

K & N? Isn't that the outfit that claims their air filters last 100,000 miles? OOOOOOOK[/quote

Why must you guys insist on posting junk on every thread??

 

[EvanD]

Originally Posted By: AuthorEditor
Pretty good description of what a PCV valve does and how it works here: http://workingtofu.blogspot.com/2008/07/how-does-pcv-valve-work-what-is-it.html

I'd use a PCV catch can instead of plugging it up. You still need to vent the crancase somehow.



1 good post thank you


I did like the PU comment that was kinda funny.

 

[mechanicx]

I think there is nothing to gain and everything to lose by getting rid of the positive crankcase ventilation. Some downsides as mentioned are oil sludging quicker, oil consumptiuon and leaks. No HP is going to be gained by blocking off the PCV vacuum line. Real race motors use either the exhaust to evacuate the crankcase or A dry sump that pulls the crankcase pressure low.

 

[EvanD]

I was looking into a more simple solution future plans include boost options and new intake manifold. I figured while I was here I should address this as well.

These engines also get junked up pretty fast normally and a catch can looks like a patch job to me.

I saw a post with a vw using his exhaust and a check valve in it. Looks like a sound option.

 

[AuthorEditor]

I think a lot of Corvette folks add catch cans. You can get some beautiful billet aluminum jobs that should do the trick. I think it would be interesting to see how much cruddy oil you catch with one.

 

[mechanicx]

Originally Posted By: evandostert

I saw a post with a vw using his exhaust and a check valve in it. Looks like a sound option.


Yeah that would probably be your best bet over a catch can or worse just breathers. You can still run PCV with boost and a manifold change. On a street car you still usually have manifold vacuum much of the time.

 

[Rick in PA]

When I was a young lad in the '70s I decided to replace my PCV valve with a road draft tube on my '72 Plymouth
Duster (318 engine). So I ripped out the PCV valve and replaced it with a homemade road draft tube. After only a short time I noticed yellow gunk building up inside the valve covers. At that point I came to the conclusion that PCV systems are not really performance robbing anti-smog devices but actually quite beneficial to keeping the oil clean. I haven't tinkered with a PCV system since.

 

[Hemi426]

As the name implies, the PCV is the only thing that ventilates the vapors and pressures from the crankcase. A friend of mine had an AMC Eagle 258 I-6 in which he decided to block the PCV off. Soon after that he blew every seal in the engine and oil was EVERYWHERE.

 

[Drew99GT]

Sheesh folks. The guy is asking about deleting the PCV system and just adding breathers on the valve covers, which will still vent the crankcase. He's not suggesting totally blocking the crankcase.

It will work, your engine will likely not explode, and the sun will rise tomorrow morning. You won't be contaminating the intake system with blowby gases/oil.

The best solution is always retaining the stock PCV system and adding a catch can on the PCV line to the intake. That way you're getting full crankcase vacuum and blowby contamination is caught.

 

[gathermewool]

Originally Posted By: Drew99GT
Sheesh folks. The guy is asking about deleting the PCV system and just adding breathers on the valve covers, which will still vent the crankcase. He's not suggesting totally blocking the crankcase.

It will work, your engine will likely not explode, and the sun will rise tomorrow morning. You won't be contaminating the intake system with blowby gases/oil.

The best solution is always retaining the stock PCV system and adding a catch can on the PCV line to the intake. That way you're getting full crankcase vacuum and blowby contamination is caught.


I think those commenting his blocking off anything more than the intake port weren't really reading, and just wanted to throw their .02 in for what ever reason.

I like the catch can idea over porting to the exhaust. I've never seen some one do this, but have read up on it as an option for my turbo subie, so take what I say as opinion only. Porting to the exhaust makes sense, but you've got to trust the guy welding in the bung - the bung needs to be angled down stream to work. Also, I'd think that a longer line to the exhaust would lead to more cooling and gunk build up.

Whether it be a catch can or an air/oil separator, you've got options besides breathers. As some one mentioned, there's a chance of water vapor not being vented properly and causing gunk build up, so keep an eye on that if you stick with breathers-only for a bit.

 

[eljefino]

With PCV he'll have a vacuum, however slight, under the VC. With just a breather, he'll have slight positive pressure.

If someone doesn't want the fresh air hose part of the system going to the intake, because at WOT they get oily fumes which cut octane .0001 points, okay, stick a breather on there. It'll let fresh air in at anything but WOT which will get sucked out by the PCV and life will go on.

 

[Scott_Tucker]

You need the PCV to sweep out blowby and other gases in the crankcase. There really are no benefits to removing it on a street car. Your oil will definitely get contaminated a lot quicker. Plus there will be no power benefits to removing it so why do it?

 

[mechanicx]

It makes no sense to me to delete it. I doubt a properly working engine is going to throw any more oil into the air duct than an oiled K&N air filter, although that might get caught by the MAF lol. Not that I'm a fan of K&N, but no one thinks K&N hurt performance. I never see much oil in the fresh air tube on a properly working engine.

What I think will really end up happen is you'll get more oil dilution and burning and a theoretical drop in octane without a PCV.

 

[mechtech2]

Oil, and therefore engine life, is lessened.
Oil leaks from pressure are ensured to happen!

But the PVC is a POSITIVE system. It allows the engine to make more power, for a bunch of reasons. Some guys use a dedicated electric pump to vacuum the crankcase for more HP at high loads and RPMs.

For much less trouble than filling the holes in the valve covers, you can have a working PCV system.

I can't believe that anyone would actually negate the PCV system.
Even a 'road draft ' system is better than nothing.