I don't get it either. Here is a Stocker engine, same system.
PCV vs EVAC
Moderator: Team
-
- Vendor
- Posts: 943
- Joined: Sun May 13, 2012 1:28 pm
- Location: KS
- Contact:
-
- Vendor
- Posts: 943
- Joined: Sun May 13, 2012 1:28 pm
- Location: KS
- Contact:
-
- HotPass
- Posts: 601
- Joined: Tue Nov 30, 2021 8:47 am
- Location: West Milford, NJ
- Contact:
Re: PCV vs EVAC
If that pcv system had a breather, it wouldn't build vacuum in the crankcase. Just like a vacuum pump, it needs a sealed engine to create vacuum.
'73 Camaro Z/28 NETO/N
434 SBC 11:1, 1.294, 6.178 @ 108.87, 9.81 @ 134.93 (3060#, Naturally Aspirated, Sunoco Ultra 94)
Chopper Air Port 917-589-1278
434 SBC 11:1, 1.294, 6.178 @ 108.87, 9.81 @ 134.93 (3060#, Naturally Aspirated, Sunoco Ultra 94)
Chopper Air Port 917-589-1278
Re: PCV vs EVAC
Now THAT'S a very valid point.ChopperScott wrote: ↑Tue Jan 11, 2022 5:02 pm If that pcv system had a breather, it wouldn't build vacuum in the crankcase. Just like a vacuum pump, it needs a sealed engine to create vacuum.
In effect the breather is whatever is getting past the rings.
Kevin
-
- Guru
- Posts: 1141
- Joined: Tue Feb 05, 2013 6:56 am
- Location: Melbourne, Australia
Re: PCV vs EVAC
Does anyone make a pcv using an IAC stepper? You could make it do whatever you like under any combination of rpm and load.
Re: PCV vs EVAC
I can't speak for an electric valve but I do know of this adjustable version that I had been thinking about.
http://mewagner.com/?p=444
http://mewagner.com/?p=444
You do not have the required permissions to view the files attached to this post.
Kevin
Re: PCV vs EVAC
That is what I was saying in my post. If the engine develops a problem, the 2 pcv valves would likely be unable to keep up and would pop out.skinny z wrote: ↑Tue Jan 11, 2022 5:05 pmNow THAT'S a very valid point.ChopperScott wrote: ↑Tue Jan 11, 2022 5:02 pm If that pcv system had a breather, it wouldn't build vacuum in the crankcase. Just like a vacuum pump, it needs a sealed engine to create vacuum.
In effect the breather is whatever is getting past the rings.
So much to do, so little time...
Re: PCV vs EVAC
The pan evac isn’t legal in Stock.
Not sure about SS.
Not sure about SS.
Somewhat handy with a die grinder.
-
- HotPass
- Posts: 596
- Joined: Sun Jul 30, 2017 2:24 pm
- Location: Summer Shade, Ky
Re: PCV vs EVAC
Smoke and Mirrors? Has anyone seen a Stock or Super Stock car running that set up. Just asking .
-
- Vendor
- Posts: 943
- Joined: Sun May 13, 2012 1:28 pm
- Location: KS
- Contact:
Re: PCV vs EVAC
F-BIRD'88 wrote: ↑Tue Jan 11, 2022 4:18 pmThe PCV valve does not Close @WOT. But there is a anti back fire safety valve function to stop a blow back crankcase fire. The flow pindle does move to the low vaccuum position against the pindle valve spring inside.HQM383 wrote: ↑Tue Jan 11, 2022 2:58 pmExactly. Pcv is useless on a drag car as it is closed at WOT.ChopperScott wrote: ↑Tue Jan 11, 2022 2:52 pm If it’s drag only, with no mufflers, I’d go with exhaust evacuation…
4E28BEC4-D43F-4785-88B7-F86955E1F79C.jpeg
The low vaccum position creates more flow thru when manifold vaccuum is low (wot)
Touché, I was wrong with my general statement . A correctly calibrated pcv is open at WOT. Most OEM pcv will have a spring strong enough to close the valve at WOT with a modified engine that's pulling less vac than the pcv was calibrated for.SpeierRacingHeads wrote: ↑Tue Jan 11, 2022 3:43 pm If it's useless, why does all the $45,000 Patterson Super Stock engines run dual PCV?
A proper sealed system uses the pcv on one rocker cover and on the other a sealed filler cap (not totally necessary) and the other end of the same rocker cover an open tube that goes to the base of the air cleaner for fresh air through the system. Sealed and gasses always recirculating. As someone said a breather would limit amount of vacuum in the crankcase. Something seems incomplete in those photos to recirculate air and not suck gaskets in unless the cap has some ventilation?
I’m a Street/Strip guy..... like to think outside the quadrilateral parallelogram.
-
- HotPass
- Posts: 33
- Joined: Mon Feb 25, 2013 11:33 pm
- Location:
Re: PCV vs EVAC
There are also fixed orifice type pcv valves.
There is only a anti backfire one way check valve inside and a flow orifice. I believe chev LS truck engines have this type pcv
Would be interesting to see the details of the function and baffling of the E vac/Pcv breather system on that FJ Smith Super Stock.
There is only a anti backfire one way check valve inside and a flow orifice. I believe chev LS truck engines have this type pcv
Would be interesting to see the details of the function and baffling of the E vac/Pcv breather system on that FJ Smith Super Stock.
Re: PCV vs EVAC
The setup Bill jenkins used was intake vacuum with oil seperators plus an exhaust vacuum system.It was detailed in his book on small block chevy.Using this setup he was able to pull vacuum on the crankcase at both idle low throttle conditions and wide open going down the track.According to him this setup pulled enough vacuum he had to run the crank seals backwards for sealing.
-
- Guru
- Posts: 2270
- Joined: Wed Jul 27, 2011 5:22 am
- Location: brisbane AUSTRALIA
Re: PCV vs EVAC
Unless you own or build these style of engines I doubt we will see inside of anything
My opinion is we should be thinking of what they are trying to achieve having to use that type of crankcase ventilation.
Those short blocks are more than likely turned over with a inch/LB torque wrench.
Blowby would be very low,maybe the low manifold vacuum at high rpm with that setup is worth a couple of hp and hundredths at the track.
I am sure Vortecpro put a video up a few years ago where he is spinning a short block over one handed,he must be very strong
My opinion is we should be thinking of what they are trying to achieve having to use that type of crankcase ventilation.
Those short blocks are more than likely turned over with a inch/LB torque wrench.
Blowby would be very low,maybe the low manifold vacuum at high rpm with that setup is worth a couple of hp and hundredths at the track.
I am sure Vortecpro put a video up a few years ago where he is spinning a short block over one handed,he must be very strong
steve c
"Pretty don't make power"
"Pretty don't make power"