That one little thing that has not been said. If the crank case is being vented by engine vacuum, the PCV valve is a must because it limits how much vacuum is lost from the intake tract in doing the job. It has a movable slug internally to cause the limiting action and should be installed in the position the valve is meant to work at. Venting to the air cleaner needs no PCV valve in line as it is above or outside engine vacuum operation except for that caused by airflow into the air cleaner. On engines after 2000, the PCV operation is monitored by the computer and will generate a CEL and code if there becomes a leak because it is now part of the intake tract after the Mass Air meter and can influence the air/fuel ratio as "un-accounted for" air.
Good point, Ken. Reminds me of when Smokey Yunick would get around carb size restrictions by over jetting the carb and then having an "air leak" in a vacuum line to supply additional air.
Doesn't it also help keep all the oil vapor and other airborn particles inside your engine from building up on the valve springs and inside the valve covers? I thought generally when you tear apart and engine and it looks like crap inside is because of a faulty PCV system ...
My race motor uses a vacume(sp) pump that runs off of a belt from the crank. When I picked it up from my motor guy, I threw A Fit about the pump robbing power. He showed me the dyno sheet with the pump and without 17 horsepower differance to the good. I just shut my mouth and listened to him from then on.
Yep, or in other words "sludge". The engine that is now in my '72 from my '74 Grabber had a good bit of sludge in it. The previous owner changed the oil regularly, but apparently he didn't maintain the PCV system. The PCV valve had litterally fallen apart, causing a high, rough idle. Now, nearly 26,000 miles later with regular oil changes and maintained PCV system, the engine has practically cleaned itself out. There are almost no traces of the grime that was in it. The PCV system seems to be one of the most neglected things on these cars.
One of the most neglected, as well as one of the simplest and CHEAPEST to maintain. I think I have a total of $6 invested in my entire PCV system.
Sludge is the by products of combustion and chemical reactions. With todays' oils and crankcase ventilation, there should never be much accumulation in an engine that has it's oil changed at least 5000 mile intervals and operated long enough each time to heat and drive off the larger part these contaminates. . On the vacuum pump; this is sort of old tech now but draws a vaccuum in the crank case that the crank and rods don't have to work against windage at high rpm as well as keeping little oil leaks from losing oil in a race car. The general rule is not to draw to much more than about 10 to 12 inches of vacuum in the average engine and use a "calibtrated air leak" as regulation (at top rpm) while watching a vacuum gage connected to the crankcase. This, carried to extremes can draw air right through the front and rear main seals as well as other places not too good on sealing and in extreme cases, run valve stems low on lube as well as steal lube from the rear main bearing or any place the vacuum will try to draw air through. An engine builder who has experiece with this should be trusted. . Old Smokey was a master and did a lot of things the rules never specified. I remember reading about a time when he took an engine apart while a lot of people watched and he still fooled them right before their eyes and they never picked up on it. Another time using the clutch and flywheel as a little help with a little forced induction, and another using the frame rails to hold extra gas. Some have a name for it called cheating but I just call it a little constructive magic when not addressed by the rules. Iv'e been known to pull some of it myself in the past.
Add a separator unit to the line from the pcv valve to the carb like this one...... You can buy them at Lowe's or Home Depot in the air compressor section. Traps oil vapor and keeps it from depositing on the valves/chambers in the engine. Has a drain at the bottom to remove excess buildup. Separator, couple of fittings, and an el-cheapo bracket are all you need.
Where does the other end of the line go? Seems like you could just leave the exhaust end of that filter open and let it go...
If you are runing a vacuum pump one end goes from the crankcase to the pump the other end goes from the pump to the intake manifold where the gasses you suck out of the crankcase get burned. If you run a separator it goes between the crankcase and the pump.
Now that is cool. I'll have to run down to Home Depot tomarrow and get me one of those. Thanks for the tip!
That IS cool. I was thrown off at first...I thought this was replacing my breather cap, and wondered where the outlet went. This goes on the PCV side... Seems like you could use it on the breather side, also, and just run the exit-line either open, or down to an area away from the engine, so any fumes/smoke that might get through would exit below the car... Jamie, let me know how it works, and how much it costs you...it might not be worth $20+ just to keep a little smoke off the valve covers. In fact, that smoke works like a chrome polish...just wipe it in with a clean cloth, and VOILA!!! clean shiny valve covers
