Crank case extractors working to good

[Kdub]

I have a cheaper set of crank case extractors on my SBC 400 and they seem to be working to well. After a 1000' pass the valve cover vent caps have oil all around them and dripping off the engine and the exhaust is smoking bad. The valve covers I have didn't come with holes in them so I put holes in the center of them between the pairs of rocker arms. I'm using the rubber push in baffles with Dodge style push in caps. Are the valve covers my issue? And if so what kind should I use? This has me scratching my head and I wrapping shop towels around the filler caps and blowing oil smoke ain't right.

[cv67]

Do you mean the rubber push in grommets that hold the breather?
If so you may need an internal baffle to keep the oil in the cover.

[Kdub]

Yes crankcase evacuation, I couldn't remember what they were called, senior moment I guess. Yes they are the rubber push in type but they are the ones with the baffles made into them. The motor is near 15:1 compression and has six 1000' passes on it.

[dirtracr5]

Your check valve may be blow allowing positive pulses into the crankcase. We use a baffled tank setup with a -12 fitting on the valve cover. An aluminum tube is welded under the fitting and runs down between the rockers and sits about 3/4" off the head. this prevents oil from being sucked into the exhaust.

[Kdub]

Ok I'll check that out. I did check them before and the had vacuum at idle which is about 1200 rpm.

[Baprace]

Is there a stud girdle on this engine ?

[Kdub]

No stud girdle. I do have oil restricted to the top end with oil restrictors.

[JWRE]

It doesn't matter whether you're running restrictors, baffles, or a girdle, no amount of oil should be blowing out around the grommets. If the evac system is working then their will be no positive crankcase pressure to push oil out. The majority of the time I see people with this problem, it's because their isn't a tight seal between the grommets and the hole in the valve cover, especially if you drilled them yourself because the hole saw size they recommend in the instructions is too big. And/or there's a leak elsewhere on the engine. It has to be 100% sealed tight, same as if you were using a vacuum pump. Pull the valve covers and clean thoroughly clean them around the grommet holes them silicone the grommets in place. Then look for other potential leaks like underneath the distributor or corners of the intake endseals where the intake and head meet. Whenever I have trouble finding a leak that's keeping the vacuum pump from pulling like it should I've gone as far as blowing smoke in the engine with a cheap smoke machine I bought at a local party supply store, and the leaks show up immediately. Even in places you'd never think to look. This is of course assuming that the tubes are in the correct location in your collectors. If you solve the issue, it's still wouldn't be a bad idea to put a baffle over the holes in case you ever blow a head gasket, or burn a piston and pressurize the crankcase to keep from blowing oil under your tires. The system is designed so that oil doesn't get into the exhaust, but it's not perfect. One more thing I'd personally do is use a set of valve cover gaskets that are rubber coated/steel core. I can't remember the P/N, but they're available everywhere. Not only do they seal better, but they don't push out when over tightened and maintain their shape between that long span between the two bolts on a SBC. They'll also be the last set of valve cover gaskets you'll ever purchase.

[Abbottracingheads]

Pull the breather with it running and put your hand over it. You should feel a fluttering suction on the breather. If you feel pressure the check valve is bad and will pressure up the engine and make it smoke. I have seen this condition more than once.

[Baprace]

you have mail.

[engineguyBill]

There are three very important elements that are necessary for a crankcase evacuation system to function properly.
1. An oil SEPARATOR installed on each valve cover. Most aftermarket suppliers use Chrysler oil separators in their kits. There IS a difference between breathers and separators. The separators must be installed in the valve covers with no air leakage - i.e. tight fitting grommets.
2. A check valve installed close to the collectors. Most suppliers of evacuation kits use a check valve that has NPT (pipe) fittings that install directly onto the pipe nipple that is welded into the collector.
3. Pipe nipple installed correctly in the collector. The best installation involves the nipple welded into the collector, pointed towards the collector exit; at a 45 degree angle to the collector centerline and projecting into the collector by 1 to 1.5 inches.

Crankcase evacuation system works best in an engine without mufflers.

[Jeff Lee]

I just installed this pan-e-vac on my AMC engine last week. There are no holes in the valve covers to seep oil from. The factory uses a oil fill tube like an old SBC. To this a two-piece breather was welded and a AN fitting was threaded to the breather. From there it follows the blue tubing to a T-joint then off to each collector with the standard pan-e-vac parts. Oil is added through the breather once the top is unscrewed off. There is scotch-brite inside the breather to separate the oil before it hits the AN fitting. The engine is sealed tightly.
I have not even fired it up yet but assume it will work correctly.