FI, what to do about PCV system
03-13-2008, 03:11 PM
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FI, what to do about PCV system I have a centrifugal SC, Novi 2000, on my Vette. Right now for a PCV system I have one line that runs from the valley through a catch can, through a McMasterCarr check valve and into the intake. I also have a breather on the pass valve cover.
Under boost I am getting oil out of my breather and onto the engine. Obviously blow-by. What do I need to do to prevent this? I have considered replacing the breather with a vented catch can and at least the oil will go into there. I am afraid of getting oil onto the blower belt.
Thanks
Chris
Under boost I am getting oil out of my breather and onto the engine. Obviously blow-by. What do I need to do to prevent this? I have considered replacing the breather with a vented catch can and at least the oil will go into there. I am afraid of getting oil onto the blower belt.
Thanks
Chris
03-13-2008, 03:36 PM
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How much oil are you seeing?
I run almost the identical same system as you.. mcmaster check valve, breather etc but I'm getting lots of oil. My tuner said I've probably got a busted ringland so I'm planning to forge the motor this summer.
I run almost the identical same system as you.. mcmaster check valve, breather etc but I'm getting lots of oil. My tuner said I've probably got a busted ringland so I'm planning to forge the motor this summer.
03-13-2008, 03:44 PM
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I don't know what you call a lot, because a little oil can make a big mess, but I would guess and say that after 3 passes at the track, I probably get 1-2 tablespoons of oil out the breather. I did a compression check and all looked good, but I still need to do a leakdown test. I don't think my rings are going bad though, because the car still makes good power and I am not burning oil.
I have also looked into the Krank Vent system, but it is pricey at $100 for 2 check valves.
I have also looked into the Krank Vent system, but it is pricey at $100 for 2 check valves.
03-13-2008, 07:13 PM
#4
I am running more than 15#'s of boost in my Z28, and not even running a catch can system. I am just running 4 breathers on the valve covers (two large, two small), and other than wiping just a little oil off the underneath part of the hood near the valve covers after long extended periods of WOT and lots of boost, I have had no problems what-so-ever.
03-13-2008, 10:17 PM
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I am running more than 15#'s of boost in my Z28, and not even running a catch can system. I am just running 4 breathers on the valve covers (two large, two small), and other than wiping just a little oil off the underneath part of the hood near the valve covers after long extended periods of WOT and lots of boost, I have had no problems what-so-ever.
03-13-2008, 11:23 PM
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Im currently running breather also. This is only because with a pcv system on my car with a catch can and ls6 mod i would still get alot of oil burning when i let off the gas. Id like to run a pcv because i do alot of short trip city miles and i dont was moisture to build up in my oil.
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03-14-2008, 09:09 AM
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I think I might try running a large line, 1/2 -3/4", from teh valve cover to a vented catch can. At least this way I can capture the oil from the blow by and still provide a path for the pressure to relief. If I can find a check valve that big, I might put it inline which would allow pressure out, but not pull air in under vacuum.
Another question. If you completely sealed a motor, would it be possible to pull so much vacuum that you damage the seals?
Another question. If you completely sealed a motor, would it be possible to pull so much vacuum that you damage the seals?
03-14-2008, 09:16 AM
#10
I think I might try running a large line, 1/2 -3/4", from teh valve cover to a vented catch can. At least this way I can capture the oil from the blow by and still provide a path for the pressure to relief. If I can find a check valve that big, I might put it inline which would allow pressure out, but not pull air in under vacuum.
Another question. If you completely sealed a motor, would it be possible to pull so much vacuum that you damage the seals?
Another question. If you completely sealed a motor, would it be possible to pull so much vacuum that you damage the seals?
A brake booster check valve would probably be big enough to cover it.
Completely sealing the motor can cause a seal problem from vacuum, or from boost (pushing oil out around the seals, possibly eventually pushing out a seal).
03-15-2008, 09:30 PM
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Has anyone ever vented their valve covers between the air filter and the turbo/SC? I am thinking that wheel is always sucking in air, and it would be better than just going to atmosphere. The faster the wheel will spin, the more air the turbo will suck, and there will be no boost in the crankcase. I am not sure how much vacuum it could draw (if any), but some other cars vent the pcv before the TB.
Only negative thing I could see is the oil/gas vapors messing with the maf, and I am not sure that would even bother it all that much (Nothing an SD couldn't fix).
If this is a horrible idea... Please let me know.
Only negative thing I could see is the oil/gas vapors messing with the maf, and I am not sure that would even bother it all that much (Nothing an SD couldn't fix).
If this is a horrible idea... Please let me know.
03-16-2008, 08:46 PM
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A vac pump setup is ideal and will help seal the rings.
If your on a budget, a nice way to do it would be have a -12 weld on installed on a valve cover and ran down to a catch can mounted on the frame rail. Moroso/allstar sells these breather catch cans that have a -12an port. Looks good and works great.
If your on a budget, a nice way to do it would be have a -12 weld on installed on a valve cover and ran down to a catch can mounted on the frame rail. Moroso/allstar sells these breather catch cans that have a -12an port. Looks good and works great.
03-17-2008, 04:52 PM
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I don't think any sponsers sell a kit like this so I'm going to go ahead and post it.
http://www.gzmotorsports.com/LSXVPK.html
My opinion is that if your going to have a forced induction/nitrous car, it should be done the right way and messing around with a pcv system just isn't the way to do it. Especially when a kit can reliably pull constant vacuum, not loose any accessories, and maybe gain a few horsepower...only downside is cost...
http://www.gzmotorsports.com/LSXVPK.html
My opinion is that if your going to have a forced induction/nitrous car, it should be done the right way and messing around with a pcv system just isn't the way to do it. Especially when a kit can reliably pull constant vacuum, not loose any accessories, and maybe gain a few horsepower...only downside is cost...
Last edited by Lythropus; 03-17-2008 at 04:57 PM.
03-17-2008, 06:05 PM
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I don't think any sponsers sell a kit like this so I'm going to go ahead and post it.
http://www.gzmotorsports.com/LSXVPK.html
My opinion is that if your going to have a forced induction/nitrous car, it should be done the right way and messing around with a pcv system just isn't the way to do it. Especially when a kit can reliably pull constant vacuum, not loose any accessories, and maybe gain a few horsepower...only downside is cost...
http://www.gzmotorsports.com/LSXVPK.html
My opinion is that if your going to have a forced induction/nitrous car, it should be done the right way and messing around with a pcv system just isn't the way to do it. Especially when a kit can reliably pull constant vacuum, not loose any accessories, and maybe gain a few horsepower...only downside is cost...
