Crankcase pressure. Need some insight...
Crankcase pressure. Need some insight... Hello. Crankcase pressure seems to rise (naturally of course) when I spray the car. I noticed my dipstick tube kind of misted oil on my valve cover a bit. Would I see any benefit with running a breather/filter on the valve cover? I am currently running the stock PCV system (the valve is relatively new and clean) with the fresh air hose going to a canton valve cover (stock location). Nothing special. Any input would be greatly appreciated! I am trying to avoid spending $600+ on a vacuum pump setup OR tearing the short block down and doing properly gapped rings.
TECH Enthusiast
Joined: Mar 2009
Posts: 680
Likes: 8
From: Clearwater
not really because if you manage to keep the breather from falling off all the time you will pobably notice the oil shooting out of it instead. you could just run a dump tube out the valve cover and down the back of the motor near your exhaust. remember whichever one you do make sure to cap off the rest of the pcv system.
Hmm... I run a 3" x-pipe setup with bullets before the axles. I would say it is relatively free-flowing. Would it be sufficient enough for a crankcase EVAC kit like the one you are talking about? I could always remove the bullets and just put turn-downs.
Nothing up front. Definitely have a slight weep at the rear main, but that was since I put it in a year ago). It is not enough to be a concern. I am sure the excessive crankcase pressure does not help though. So would the evac be a viable solution?
There are nay sayers and there are those that actually run them. I run it and I pull 18 in of vac at wot. When I had the engine built by Clayton racing, I was told it would be in my best interest to run it. That was by Jerry Clayton who built top fuel engines for many years. So to me, his word is gold to me seeing the many years of success and records broken by him and his team. The kits have been around many years and on many cars. It's not a gimmick and for the $50 it costs it isn't going to break the bank. Just make sure to install them in the correct locations. They siphon air as it passes through the exhaust through check valves into the breathers in the valve covers. Mine whistle pretty loud. Think procharger sound. I measured vac with a shortridge digital differential pressure meter I use for work. The meter is $2500 and is proof enough for me what they are actually doing.
Only problem I had w/ an evac kit is condensation building up at the check valves causing them to rust if the car sat for an extended period of time. The pass side clogged up completely on me and the clue was I was blowing the oil cap off under decent boost. I just went back to breathers until I pick up one of those high dollar vac kits.
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Verdad Gallardo Would pushloc hose be sufficient to use for this setup? I am using it for my trans cooler lines. I can only imagine it will be fine for this, right?
Teching In
Joined: Feb 2010
Posts: 42
Likes: 0
From: Bartlett, Il
I use regular heater hose--
also I might add that in my drag car there is oil pressure on one side of the tack and crankcase vacume on the other side----required reading at the finish line every pass---
also I might add that in my drag car there is oil pressure on one side of the tack and crankcase vacume on the other side----required reading at the finish line every pass---
I have WOT crank pressure as well, and I was running breathers, which helped, until oil splash out of the breather onto the header at an autocross race caught fire. For high vacuum, low throttle evac, I left the stock PVC system with an inline air/water separaterI now run hoses from each valve cover, to a T, then into a 22oz catch can with breather on the top sitting in the fender where a CAI filter usually sits. This allows air to come into the system via the breather on the catch can when the PVC is running and then when at WOT, the excess pressure pushes into the catch can and vents out the breather. This way you can vent the pressure the same way that a breather filter does, without any of the oil mist or splash-out that can happen from one just sitting on your valve cover. Everyday that I drive it I usually empty about an ounce of fuel/water that vaporized out. I can post a pic later of my setup if you would like?
I have WOT crank pressure as well, and I was running breathers, which helped, until oil splash out of the breather onto the header at an autocross race caught fire. For high vacuum, low throttle evac, I left the stock PVC system with an inline air/water separaterI now run hoses from each valve cover, to a T, then into a 22oz catch can with breather on the top sitting in the fender where a CAI filter usually sits. This allows air to come into the system via the breather on the catch can when the PVC is running and then when at WOT, the excess pressure pushes into the catch can and vents out the breather. This way you can vent the pressure the same way that a breather filter does, without any of the oil mist or splash-out that can happen from one just sitting on your valve cover. Everyday that I drive it I usually empty about an ounce of fuel/water that vaporized out. I can post a pic later of my setup if you would like?
Probably. Not sure what the source of the problem could be, but it probably requires time and money lol. If I can find a way to reduce crankcase pressure (for whatever reason mine is that high) I will be satisfied. It is not crazy. Just a small mist out of the dipstick.
Here is a pic of my engine bay below. You can see that I have closed 'breathers' (Spectre brand from AZ), that I removed the inner foam and drilled out the 'baffle' from the 1" opening where the breather sits into the valve cover. This made it basically an open flowing item at this point. I then ran 5/8" heater hose from each breather to a 'T' with 3/4" hose coming off of that and into the homemade catch can. The lid of my catch can I affixed a standard filter breather to allow air to flow in at normal cruising, and then pressure to vent out at WOT. So far no dipstick popping out at WOT. You can also see my air/oil separator that I placed inline with the stock PCV breather line from the PCV valve to front of intake.
Here is my homemade catch can (bad pic):
