Crankcase ventilation ??

What is everyone doing about engine crankcase ventilation?  I am not sure if I should restore the factory style positive crankcase ventilation system, or just throw a breather in each valve cover, or what.  
1969 GTO, YS code 400, 350hp/445 ft lbs of torque (stock specs), LT headers, H-pipe, 750 Holley 4160, Ignitor II ignition.  Complete Painless wiring.

On my regal I have the pcv in the valley pan and a breather in one of the valve covers.  
professional hi-performance engine builder

Horsepower sells engines and torque wins races

Without the pcv you will spew crud all over that nice clean engine compartment.The pipe with the pcv work fine just like the general intended.Breathers in the valve cover look cute but do not control crankcase vapor well.I recently retrofitted a pcv to a 59 desoto and the guy keeps raving about how clean it stays.Try it.  

I have the PCV valve in the valley pan with a hose to the carb, like factory.  But, I just got new valve covers and neither side has a screw in oil cap, so I guess I'll just buy a pair of breathers to stick in the each valve cover.  But, like you said, that would not really maintain a positive crankcase ventilation, and I suspect the PCV valve will not really perform like it's meant to.  Ideally, I want a well-performing and positively circulating system to scavenge unburnt vapors.  Maybe I'm over analyzing this.  Haha  
1969 GTO, YS code 400, 350hp/445 ft lbs of torque (stock specs), LT headers, H-pipe, 750 Holley 4160, Ignitor II ignition.  Complete Painless wiring.

You are over analyzing. A 350hp motor has no special requirements. The difference in positive pressure or crank case vacuum is only 1% increase of power. Factory or sealed valve covers and a PCV valve are that you need. You are not making the power to have excessive crank case pressure to require addition evacuation. At the 450hp level breathers are required, over 500hp an evac system into the exhaust will keep oil from blowing out the breathers on the engine and over 600hp a vacuum pump is required, but even then the most you can gain is 6hp at best.  

Oh, I see.  That's awesome!  Alright, I'll just keep it simple... for now, until I start making over 600 hp.  While on the PCV topic, I have been working on getting my engine tuned up and running well.  I noticed the PCV valve in the valley pan is clicking (rapidly opening and closing) with the engine running at idle.  What would cause this?  
1969 GTO, YS code 400, 350hp/445 ft lbs of torque (stock specs), LT headers, H-pipe, 750 Holley 4160, Ignitor II ignition.  Complete Painless wiring.

The valve will close only when there is back pressure on the valve from in the intake. You likely have a valve that is not sealing. The valve lash or preload may be too tight, debris could be on the valve or seat, or a valve may be bent.

This can be found by pulling the carb and crank the engine listing to the intake or do a leak down test of each cylinder.  

I have compression in all cylinders (140-150psi).  Running compression numbers are all between 80-90psi as well.  The valve preload is set at 20 ft/lbs.  
1969 GTO, YS code 400, 350hp/445 ft lbs of torque (stock specs), LT headers, H-pipe, 750 Holley 4160, Ignitor II ignition.  Complete Painless wiring.

pcv system.. is needed on all but full race motor.. those just use breathers or an oil catch tank...

at idle.. the vacuum is high...  the valve in the pcv is pulled into tight.. only pulling a little flow...  under load.. the vacuum drops...  the spring pushes the valve away from the opening.. letting more flow into the intake..  when the engine gets to cruising speed... the intake vacuum builds again.. pulling the valve into the opening again... reducing the flow...  so the PCV if properly selected is self adjusting..

the trick...  you have to have breathers...  at least one... with a filter on it.. why a filter... most of the time... the pcv pulls air into the breather.. without a filter.. you can be pulling in dirt..  sand.. dust...


without breathers... idle vacuum will create vacuum in the crankcase...  pulling the oil pan in.. pulling the valve covers in... trying to pull the gaskets out of place...

but when the engine is under load.. the blowby can exceed the flow rate of the PCV valve..  this builds pressure... it can blow out the valve cover gaskets.. the oil pan gaskets... on pontiacs... it can also blow out the lifter cover gasket..

there are flow rates measured at the breather opening.. to make sure the pcv valve has the proper calibration..  too much... the engine will burn oil...  not enough .. and it will spread oil out the breather .....


the pcv system also keeps the amount of gasoline vapors in the crank case down...  

I have a pretty solid understanding of how the PCV system works and what purpose it serves.  What I am having trouble with is why my PCV valve in me engine clicking (rapidly opening and closing) while I have good compression in all cylinders and good running compression in all cylinders.  Also, I have no vacuum leaks and a brand new 750 Holley.  
1969 GTO, YS code 400, 350hp/445 ft lbs of torque (stock specs), LT headers, H-pipe, 750 Holley 4160, Ignitor II ignition.  Complete Painless wiring.

are the intake manifold vacuum readings bouncing around..

is the pcv a generic version that was sold at a chain parts store... so it might have been one of the sort by shape ... not sort by flow rate..  

Yes, the vac gauge vibrates rapidly between 16" and 17".

The PCV valve I got is a Fram unit that I ordered from Summit after entering the year, make, model, and engine.  So, it should be specifically for my engine's flow rate, but it wouldn't surprise me if it wasn't, and it was really just a generic "universal" valve of the correct size.  
1969 GTO, YS code 400, 350hp/445 ft lbs of torque (stock specs), LT headers, H-pipe, 750 Holley 4160, Ignitor II ignition.  Complete Painless wiring.

if your vacuum gauge is bouncing... its not the pcv usually...

its something in the engine...

a valve adjustment that is to tight...   so its holding one of the valves part way open...

sticking valve...

misfiring ignition system...   plug wires 5 and 7 too close...

carbon tracking inside or outside the cap where the spark is moving toward an earlier cylinder..

i would let the engine idle... with the vacuum gauge attached and visible...   pull the spark plug wires off the cap on at a time...  if you have HEI... and a really sharp point on your test light... you can push the test light straight down through the middle of the distributer cap boot ,,,   with the other end of the test light grounded... it will cancel the spark to that cylinder...    move the probe around... when it stops bouncing... you have found the problem cylinder...

examine the wires on that one and the ones next to it... on the cap... so if it smooths out when you cancel the number six wire.. examine the number six wire... ohm it...  make sure the metal terminals are firmly attached...

then examine the 3 and the 5 wire... as those are on either side of the number six...    1843   6   572.....  

ifs its not in the ignition.. including a cracked insulator on the plug...

try readjusting the valves on that cylinder....  check with a compression tester...

it could also be a worn valve seat...   worn valve guide...  flat cam...  

but you can usually narrow down the problem cylinder with the pulling of the wires one at a time...

after you are done.. spend 2 minutes and make sure that you have pushed the wires all the way back into the cap..

i used to have a boss... who would pull the wires out to find a misfire... and the misfire would get worse... as have the cap terminals were pulled out of the cap...

if the vacuum reading smooths out as you speed up the motor... look for worn guides...

but i would bet an ignition misfire... cross fire...  or sticking valve..


when i ran a cylinder head rebuilding department ...  i put together every head with some stay lube moly graphite assembly lube.... this is slightly different than normal assembly lube...  it leaves a graphite and moly behind as the liquid works its way out.. i even put a big dab on the side of the valve stem where the seal slips over.. lubes the stem and guide ....

when just a few drops of oil is used to lube the guide... and you have a ring retained valve stem seal.. where does the lube come from???????  

COmpression is 140-150 psi in all cylinders.  Running compression for all cylinders is 80-90 psi.  The plugs are not fouling out anymore ever since I replaced the leaking carb with a new brand Holley 750.  The plugs all still look brand new, as they should.  The valves are set a 20lbs.  It's got new Taylor Thundervolt wires and full Pertronix electronic ignition.  I'll try unplugging each plug wire one at a time and observing the tach to isolate a problem cylinder (if one exists).

The car runs pretty well.  Better than it has in a long time.  If I floor it, it back fires, and then takes off.  It's got a little delay in throttle response.  
1969 GTO, YS code 400, 350hp/445 ft lbs of torque (stock specs), LT headers, H-pipe, 750 Holley 4160, Ignitor II ignition.  Complete Painless wiring.

I grounded out each plug wire one at a time with the engine running at fast idle (about 1,100 rpms) and observed the decrease in rpms.  Each grounded wire decreased the rpms by about 40 rpms, which tells me that each cylinder is contributing to engine performance equally.  I also did a leak down test.  Each cylinder (on compression stroke with both valves closed) exhibited about 6% to 10% leakage.  
1969 GTO, YS code 400, 350hp/445 ft lbs of torque (stock specs), LT headers, H-pipe, 750 Holley 4160, Ignitor II ignition.  Complete Painless wiring.