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Hole in side of block??


TheErictag

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There's no source of vacuum to help evacuate the system . It's just vented to the atmosphere . And if that filter assembly , or whatever it is , doesn't breathe properly than it's just a plugged system. 

I would run a pcv valve off of some vacuum port on that manifold . Put a small filter on the valve cover

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I see what the PO did . It's actually not a bad setup.  Only 2 major mistakes. It is a vented Catch Can. There is a K&N style filter on top of the catch can. The first mistake is that you ca not plumb a vented Catch can into a PCV system. You have to use a sealed or recirculating Catch Can. Other wise you can't create any Vacuum at the block breather side. Vented catch cans are used on Vent To Atmosphere systems like on race cars. The second mistake is that the VC hose should not have been tee'd into the hose connecting to the catch can. Again, that is for a vent to atmosphere style system. NOT a PCV system.

What the PO should have done is used a Sealed Catch Can ( Or oil separator ) and put a small K&N style breather on the Valve cover. Air must be sucked in at the VC, flow through the crank-case and then sucked out at the block breather and into the Intake manifold to be combusted. At WOT airflow is reversed and blow by gases will blow out of the VC vent.

There actually is a vacuum source if you look carefully. In the second picture there is a black hose that goes into the base of the Intake manifold just below the Holley carb. There is a GM PCV valve in that line ( Small silver can ) 

Bottom line, you really don't need the catch can system at all on the L-Serier's ( For street or weekend warrior use ) . The factory PCV and baffling system are very good. 

Personally, I would get rid of this system and revert back to a factory style PCV system. K&N filter on the valve cover, then use a factory PCV valve at the Intake manifold. It should be threaded for the Nissan PCV valve unless PO mucked about with it. Then run a hose from the Block breather tube direct to the PCV. That will duplicate the factory system and should work fine. 

 

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Only thing I would be cautious about, is if PO removed the baffle screen and baffle plate in the breather block. You could use an LED Endoscope ( As cheap as $15 on E-Bay ) to look into the breather tube and confirm that the oil screen and oil baffle are in place.  You could even stuff a wire down the breather tube to see if it hits the screening. 

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The routing of those breather tubes is just fine as long as the breather/catch can is adequately vented. There should be no restriction in the system allowing for plenty of air volume to pass back and forth through the filter/breather/screen. A PCV is not necessary. I run nearly the exact same setup on my race car. Find a way to secure the block tube. Someone mentioned JB Weld. You could also try slightly deforming it to tighten the fit or scoring the sides or adding little spot welds on the tube's exterior, etc. Perhaps try painting the exterior of the tube, letting it thoroughly dry, then driving it back in. My problem in this area has always been just the opposite. Mine have been very difficult to remove. Good luck.


Sent from my iPad using Classic Zcar Club mobile

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 A Race car is not a street car. Race cars get frequent oil changes and are run hard all the time. The hard running also burns off moisture that condenses in the crankcase. 

Street engines are a different matter. Contaminants and acids build up in the oil from blowby and water condensation from short runs. Oil analysis from street vehicles  running a PCV system and street vehicles not running a PCV system consistently show rapid degradation of the oil in the VTA systems compared to a properly functioning PCV system. PCV system  " deletes" are not a good idea on street engines.

It is interesting to note that GM has been running a Centrifugal oil separator on LS engines for several years. You often see centrifugal oil separators on BMW's and other high performance systems. The Mann-Hummel Provent system is becoming very popular with the Forced Induction groups. It incorporated a valve to change airflow direction under boost.

https://store.034motorsport.com/catch-can-air-oil-separator-provent-200.html

Mann Hummel Provent Technical data

Other advantages to a functioning PCV system are improved ring seal and less leakage through seals and gaskets. Negative crankcase pressure is also a desirable feature on Racing motors. Modern Dry sump systems create considerable negative crankcase pressures and substantial improvements in HP have been documented for several decades.  Wet Sump race cars will often  run Vacuum pumps to generate negative crankcase pressures. 

 

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