I honestly have never heard of that. BTW, I owned a 65 Wildcat 401 many years ago but can't remember where the pcv valve was located. Hell I don't know if it even had one!

 

No big deal :thumbs:

I just wanted to have the engine look a bit prettier, so I installed the PCV
valve on the intake manifold to try and hide another hose.

The moral of the whole story is that it did not work for whatever reason (no baffle) so I had to therefore cut a hole in my brand new Aluminium Dart valve cover......both actually, because the one cover has the PCV valve and the other cover the breather cap.

 

Cardo0.....I did some research and I now understand what you mean about exhaust evacuation systems......Thanks :cheers:

 

Cardo0 said: sorry but the spring can't push both ways, I call :bs :_dupe:

 

I put the PCV in all my manifolds, you have to fab up a sheet metal baffle and epoxy it to the bottom of the intake over the valve, plus I also use a lifter valley baffle...works good, looks good.....



[Modified by yellow 72, 3:59 PM 5/7/2004]

 

Ah, nice to see someone that believes me.....and that has done the job of installing the PCV on the intake satisfactorily.
It certainly does look better than the hose running from the valve cover!


I guess mine would have worked if I had installed a baffle :thumbs:

 

I use a PCV valve with an open baffle system going to a remote "puke tank" on my 7300RPM LT-1. I agree with with yellow 72 but, I plumbed my system using the old C2 Vette oil filler tube from the valley area to the carb. There is too much action going on in the rocker cover area to take the PCV feed from there, much more volume in the valley area. Without the PCV system, gas and water contaminate the oil quickly! Here is my system, not quite as clean as Yellow 72's but it works well for me will little fabrication required (I know the header is missing, I was welding an O2 bung on it and someone wanted to see my Accusump feed to the front oil galley so I quickly shot the photo for them.)
[IMG][/IMG]


[Modified by Solid LT1, 3:49 PM 5/6/2004]

 

The one thing I'm not a 100% on, the breather element (in aircleaner on my '73) gets oily, not dripping, but oily just the same. I very seldom have a WOT situation, so why is it dirty. I understand air moves opposite way during low manifold vacuum, but still.... :confused:

 

I have never seen the PVC on the intake, I bet no one runs the PVC off the vaccum advance port on a Holley 4150 like I do though :lol:

 

Breather elements get oily or dirty. Some is oil, some dirty blowby gas from the crankcase. It will be REALLY oily if you have a ring problem.
My $0.02, Oil cap on one valve cover, baffled breather with hose to air cleaner on the other. Simple.
Gary

 

Sorry but, I have to disagree with you. PCV stands for POSITIVE Crancase Ventallation, you are using a Passive system and the fuel vapors and water condensation will remain in the system and break down the engine oil properties WAY sooner than if you use a PCV set-up. You may not want to use one but going to the intake system but, then you could hook up a pan evacuation system to the exhaust system to give a vacuum scavenge of the crankcase vapors. I would NEVER run a long term engine without some kind of PCV system. Most race systems today actually try to created vacuum in the oil pan area either through a multi-stage dry sump scavenge system or by using a engine driven vacuum pump (the early systems actually used a Saginaw A.I.R. air pump and are basically based on that pump even today.)

 

OK - I get to chime in with my experiences...

IMO:
- "Positive" in PCV means the crankcase is positive pressure due to blowby. You are venting the positive crankcase.
- The typical system installation is with one valve cover vented through a valve to the carb creating a source of low pressure to draw the air out of the crankcase. To increase efficiency there needs to be an intake provided somewhere. This is the reason for the inlet on the other valve cover. It helps if the air is filtered, so typically this intake line is through the air cleaner for convenience. So the path of the air is into one valve cover, through the crankcase via the oil drain holes, and out the other valve cover, where it enters the carb and is burned with the intake gas.
- All liquids have a vapor pressure, and at high temps, the air in the crankcase will contain oil vapor. So the air entering your engine intake will also contain oil vapor. If your PCV setup doesn't contain baffles, the oil may actually be droplets. The reason for the PCV mandate from the EPA is to keep this small amount of oil out of the atmosphere.
- I change oil often enough that there isn't a buildup of moisture or light hydrocarbons in my crankcase, however I could tell by sparkplug color that oil gets into the combustion chambers, however slight. I now run simple breathers. :)

 

FYI True Pontiac engines also have the PCV in the valley pan under the intake. It is more-or-less baffled though.

 

It looks like I started quite a conversation here. Thanks , great stuff. I got and installed the billet breather and billet pvc valve cover devise(cross flags) looks great. There was a port on the rear bottom of the demon. I also replaced the fuel line from pump to carb. (wrong thing to do). Mothers day, The wife takes the 78 and me in the 75. She made it only one mile and the 78 died. Wrong fuel line, I need the S-line, The one I installed closed off on the bend. :withstupid:

 

Well good catch Freepop. :D But the design of the valve plug limits the flow/leakage while at high vacuum (low rpm/power) and the spring force is overcome and fully strokes valve open against spring force . When at high rpm but low vacuum the spring force moves this plug back out to increase flow for greater blow-by but with lower intake vacuum to move it. Once the engine stops or backfires the spring will force the plug all the way to seat the plug and stop flow. What really is happening is the flow to the intake vacuum is controlled for low flow at high vacuum and has high flow for low intake vacuum. And shuts to stop flow for backfires or engine stop. :rolleyes: