OldCarBum

I'm looking for suggestions for some good quality breathers that will give adequate ventilation for the crankcase for my 496 build.
The car will be a street car and I don't want oil misting around the engine bay.
I would prefer something with PCV unless you have a system or breathers that work without.
Thanks

TimAT

I'm using a push-in breather on the right (where the tube from the cover to the air cleaner was) and a stock PCV valve on the left side on my 496. So far, no signs of oil mist. I used file fit rings too.

bfit

If you intend on tracking your 496 you will need four breathers two each cover to keep crank case pressure down
When your wiping 80/100MPH off to make your corner speed that's when you will have problems with out acquit ventilation
Bfit

OldCarBum

What type of breather?

stingr69

Try the factory setup. It works well. Just need to plumb up to the air cleaner and hook up the filtered intake breather inside. Simple, cheap and no mess.

Add a catch can if you want. I had catch can once but the one I had made too much noise so I took it off.

The Money Pit

I added these for a little bling...They're Billet Spectialties pieces I think.
My 406 turns upwards of 7000, and the first time I revved that high I did see my dip stick pop, so I knew the vent was not big enough. I opened it up and drilled the vent holes bigger, and have not had the problem since.
They unscrew easily for cleaning, so the drilling was a snap.

cv67

I dont believe the factory system is adequate for longer stroke high rpm setups. I have not one ounce of blowby have done every windage thing I can think of and still have a little issue.
Toyed with the idea of using some area behind the carb pad...or in front to make a system to let it breathe more. Too lazy to pull it now.

OldCarBum

I actually purchased the same set you have and once I opened the package I noticed the vent holes were very small.
I was planning to return them because I'm wondering if I drill the holes larger if they would allow enough air in to vent my 496 properly.

7T1vette

If you don't want oil mist/smoke in the engine compartment, you NEED to hook up a PCV system on the valve covers. One hose from one cover to the filtered air prior to entering the carb/efi; a PCV valve in the other cover with hose going to a large inlet at the carb base. You just need to get a PCV valve that is appropriate for your engine size. This will keep pressure down in the interior of the engine and will also eliminate oil vapors gunking up the engine compartment. Since that system in non-functional at idle, it won't mess up idle quality; it doesn't absorb any power; and it eliminates oil vapors.

The Money Pit

A little I learned about venting. The PCV works great on stock engines because at idle the vacuum is high enough to pull the PCV closed , but under load it opens because the internal spring overcomes the lower vacuum the intake sees under load. So.....a HP engine idles with low vacuum...PCV still closes once under light throttle, but opens again if revving a lot. Pressure will build, so you must vent weather using PCV or not.

So under normal driving the engine will stay cleaner running a PCV for sure, but you still need venting for high rpm use. I drilled my vent 3/4 inch pretty much drilled out all the little holes the Billet Specialties breather had in it, but still run the filter cartridge. Try it. Worse case add another vent if you need it.

FWIW when I first installed the vents I tried just two vents not drilled out. Blew the china wall seal out the back of the intake. I resealed it and drilled one vent, and installed the PCV. No problem since.

stingr69

The way the factory system is set up, any pressure that exceeds the PCV system will flow to the intake side of the system. It would flow backward into the PCV intake filter until you got out of the throttle. If the connections are tight, there should not be much vapor misting out onto the engine, if any.

ajrothm

I run a cheap chrome push in breather on the right side (although I opened the baffle up in it some) and a factory PVC valve in the left side hooked to the carb. Absolutely no oil mist, smell or vapors. I've never had any noticeable crank case pressure issues or anything abnormal at WOT use.





That said, when I'm drag racing, I go to a less restrictive mopar style open breather on both sides....There is no chance of crank case pressure building with these in there, however, there is a lot of oil vapor (blow by) and mist, and it does get on everything. I run hoses from the breathers to the ground to keep the oil mist out of the engine compartment. I also noticed a good bit of condensate building up in these on humid days, enough to drip water on the ground..




This setup is definitely not asthetically pleasing, but it is the least restrictive. If you are going to be drag racing or road racing a lot, this is probably the best setup. However for street driving and ripping through gears occasionally, the stock PVC set up in the way to go. It helps pull moisture out of the crankcase, controls the smells/mist etc. Just make sure to run good baffled valve covers so you don't suck oil into the PVC. You definitely don't want to be pulling oil or serious thick oil mist into the intake tract...that can add to oil consumption and detonation.

OldCarBum

This is the type of response I'm looking for.
Thanks!
I plan to use my car for long periods of highway driving and the occasional spirited driving through twisting mountain roads.
I want to make sure I have enough air going in and a way for it to escape without going to an extreme system or having oil misting around the engine compartment.
I've been looking at the open K&N filter type breathers for the passenger side and the stock PCV on the drivers side.
I've seen many members run this setup, but I'm afraid I will get misting from open K&N filter type breather.

Big2Bird

Stock system is fine for that. You are overly concerned. Imho.

OldCarBum

I've always been the type to over engineer and over build everything.
I'll admit I'm just a bit OCD.

GOSFAST

One of the best style breathers that's been available and used for years now is the Offenhauser's.
They measure about 4.000" long and really dress up the valve covers/engine compartment.

Been using them for as far back as I can remember and still sell a number of them!

Thanks, Gary in N.Y.

P.S. Here's a shot of one on the bench and one "under the hood" of 540" '61 Impala. I can't think of too many builds we've done in the past that has used any type "PCV" system, other than on our 100% stock-appearing builds and most of these are non-functional, for the "look" only! If the unit is built correctly there's no need for a "PCV"!

gkull

I have not had an oil mist problem, but my rocker arms are covered up with a big stud girdle. So I don't have oil splash hitting the underside of my valve covers. I have pulled off the K&N breathers and put my hands over the breather holes and I have very little discernable blow by revving up my motor. I also build really tight motors that have very low percentages of blow by on leak down testing.

I used a hole saw to bore through my cast Dart aluminum valve covers and then cut up some one inch aluminum pipe and welded it. The K&N breathers are from Summit racing. We used the same thing on up to 800 hp non dry sumped class racing cars. You don't need 4 one inch breathers like posted above

gkull

I was going to say that you could always run one inch diameter hoses over to a remote vented breather catch can.

OldCarBum

Thanks for all the comments and opinions.
After additional research and comments on a PM, I decided to go with this Moroso breather on the passenger side valve cover and I'll be running the GM OEM style PCV on the drivers side.
If I have any oil misting in the engine compartment I'll upgrade the system then.

OldCarBum

These do work well.
I used them on several drag boat engines over the years.