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Discussion Starter #1
I've read a ton of posts on this but still don't feel like I have a conclusive answer. I've got a 400 that's getting a bit tired and has some blowby. Enough to be sending some oil through the pcv tube to the back side of my stock 2150 carb.

I know the engine was originally designed to have some vacuum pulling on the left valve cover pcv. What I'm wondering is this, will it actually hurt anything, mechanically or performance wise, to simply put in high flow K&N style filter breathers in my valve covers and just plug the pcv port at the back of the carb?

Screamin':toothless
 

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I've read a ton of posts on this but still don't feel like I have a conclusive answer. I've got a 400 that's getting a bit tired and has some blowby. Enough to be sending some oil through the pcv tube to the back side of my stock 2150 carb.

I know the engine was originally designed to have some vacuum pulling on the left valve cover pcv. What I'm wondering is this, will it actually hurt anything, mechanically or performance wise, to simply put in high flow K&N style filter breathers in my valve covers and just plug the pcv port at the back of the carb?

Screamin':toothless
It won't hurt a thing Screamin', to just run breathers in both valve covers.
That's the old school way to scavenge crankcase fumes and works very well.
However, the breathers will probably get oil-soaked after a time.

What about running an oil separator in the PCV line? That might keep things
a little cleaner....I've also seen kits that have the PCV running directly into
the exhaust, where it's burned.
 

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I've also seen kits that have the PCV running directly into
the exhaust, where it's burned.
How does that work? Is there some sort of pump? Maybe a venturi type connection? It seems like the exhaust would have too much pressure for blowby to be added to the mix without some sort of help.
 

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I would run emissions hose from the PCV into an overflow type of can with a breather filter on it. That way you can recover the oil and pour it back into the crankcase :/
 

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Discussion Starter #5
Thanks for the responses guys. I did more reading last night and have a much better understanding of what's actually going on with the whole pcv thing. I also checked under the carb and am not getting oil in there like I feared. It wasn't until I did that that I really understood that the pcv is actually serving to keep blowby oil out of my intake. It's embarrassing, but I didn't realize that it closed off the line as soon as the engine went above idle. Oh well, I guess there's always something more to learn whether it's big or small.

So, I chose to put a nice filter breather on the right side cover and an integral pcv breather on the left side hooked up to the factory tube that goes to the bottom rear port on my carb. It's working fine so far. I think most of the oily mess I got on Sunday was the result of a really el cheapo breather with a push in pcv that was not sealing up to the breather. If it turns out that the problem isn't solved, I'll post up about it.

Thanks,

Screamin':thumbup
 

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How does that work? Is there some sort of pump? Maybe a venturi type connection? It seems like the exhaust would have too much pressure for blowby to be added to the mix without some sort of help.
Kabong, I think it works by the venturi principle, with a check valve in the
PCV line. Used a lot on racecars I believe...

Glad you got it working, Screamin'. Actually that's how mine is setup;
with a K&N breather on the passenger side and the stock PCV on the
drivers side.
 
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