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Discussion Starter #1
It seems as though I have enough crankcase pressure in my 302 that it pushes oil out of the pcv (had baffle) that it coated fairly heavily the backside of my intake valves. My tube ran from pcv to tapped hole under carb. After doing this, I eliminated it altogether. Now it is coming out the oil fill breather cap and running down on the headder and really smelling great!

I ordered a typical crankcase vent kit from Jegs which is supposed to run from the valve cover to and tap into the collector of the headder. I have a complete exhaust system with Flowmaster Delta 50s run out the back.

My question is this, has anyone encountered problems with routing this type of vent system through a full exhaust system? Do you end up looking like a smoking idiot going down the road?
 

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I don't think it will work with a full exhaust system. There is a small amount of pressure in the exhaust, so that you might not get suction to the engine. The only cars you see using them are race cars with open headers.
 

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Collector evacuation only works on tuned header collectors and at full throttle. And maybe with competition-style mufflers. The standard PCV should work well unless you have more blowby than the device can handle. Make sure you have baffles under/around the PCV intake in the cover or it will suck oil from the valve covers. Oil venting on the valve cover on hard full throttle runs is normal due to little or no vacuum
 

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If you have a header evac system, put a one way check valve in the line so backpressure won't force oil out of the engine.
 

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Discussion Starter #6
Let me throw some BS thoughts out there for yall to shoot at.

FACT: The excessive oil and/or vapor seems to accumulate under hard throttle...

QUESTION: Wouldn't it be better to draw it out via the exhaust system rather than under the carb and put some kind of trapping filter or device in the line on a street/strip car?
 

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The problem with a PCV system on a HiPo engine, is the intake has almost no vacuum at full throttle where you need it most. The opposite is happening in your closed exhaust system, where the pressure is at it greatest under full throttle. At the same time these things are happening, your engine is producing the most blowby. This is when the PCV is not happening!!
If you ran an open collector, then there would be a nice usable vacuum created because of the uncorked velocity of the exhaust flow. But you don't always have that free flowing velocity in a streetable exhaust system. So the best method of crankcase evacuation would be to use some kind of pump that will produce it's own vacuum, like a smog pump. Otherwise, your stuck with a PCV that works great under normal driving conditions and doesn't really hurt at full throttle.

I chewed on that for awhile.
 

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In my humble opinion ... the PCV system is nothing more than what the automotive industry was forced into doing in order to conform the the mandates of the E.P.A.

My guess is that the best system for the engine is a simple "Free Flowing" escape for crank case pressure ...

I would say the best and least compromised system would be the system utilized prior to E.P.A interference.

That system was a simple "Draft Tube" ... which allows free flowing escape for crank case pressure and also adds a bit of "vacuum" flow once the car is in motion.


Take it for what it's worth ... It's just my Two Cents"
 

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On my car I had a set of headers with the port in the right location and it even had a slight vacuum at the breather at idle . I they are not installed correctly they will not work . It just smoked a little , I dont run them any more because , I had to buy new headers and bought really nice ceramic coated headers and didnt want to mess them up , also those headers were on it when it was race only. Remember that GM cars with SAI and an air pump use exuast check valves . they to at idle have suction on them , this is because the check valve only allows flow in one direction so as the exhaust pulses this creates a vacuum. The trick set up is to get a Late model GM electric air pump and plumb it to the valve cover breathers , and this will really suck it down! But dont run it all the time because it will cause the rear main and front crank seal to leak and the oil will mess up the pump .
 

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Hey guys, if you're experiencing oil issues from your valve covers most of the problem will be resolved with the installation of some oil restrictors. Too much oil in the top end will get sucked out the evac sys. and create lots of smoke. ATTENTION; you can only use restrictors when running a solid roller. If you've got a hydraulic of any sort you NEED that oil.
 

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Collector evacuation only works on tuned header collectors and at full throttle. And maybe with competition-style mufflers.
I have a crankcase evac with 3" pipe and Magnaflow mufflers. It actually has a lot of suction at idle. If you remove the breather and put your hand on it, you can feel a strong suction.

The check valves (that screw onto the collector bung) are often CRAP in these kits. GOOD ones are available from NAPA. Order part # 2-29000

These kits will probably not work with small pipe and anything other than 'straight through' mufflers.

I HIGHLY recommend the NAPA check valves. They are around $19 each.

edit... Dang, this thread is old! LOL!

Good Luck!
 

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Yup, this is an old one!

Mike, I have an exhaust pan evac kit ready to go with a Borg Warner check valve that Pep Boys said was the same as the Napa 2-29000. Have you heard anything bad about these? How much vacuum are you getting in the crankcase at WOT and max rpm with your setup?

I also just picked up an Aerospace 3 vane wet sump vacuum pump kit to try out after the exhaust evac at the track. Should be interesting to see the difference assuming I'll be making a fair bit more vacuum with the pump. Well, I sure better be anyway.
 

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pan evac system will work even with mufflers like no2mike said, work with iron stock manifolds also, just have to know were/how to put the tube
 
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