We are currently running on the new domain and server: www.Speed-Talk.com

IMPORTANT: Update your bookmarks to https://www.speed-talk.com/forum/
(Right-click the URL and select "Bookmark this link")

PCV valve or Catch Cans for street performance

General engine tech -- Drag Racing to Circle Track

Moderator: Team

Posts: 7537
Joined: Tue Mar 27, 2007 6:56 pm
Location: Ontario, Canada

Re: PCV valve or Catch Cans for street performance

Post by F-BIRD'88 » Wed Jun 17, 2020 10:58 pm

If your valve covers and or baffles are allowing oil migration into the pcv and or out the breather and you switch to a pan evac system, WHERE is that oil going?

On the RACETRACK. GrEAt for traction and SAFETY!

Look at old pictures of hyways from the 50's and 60's era.
What do you see? Black streak down each road lane.
That streak is OIL. NICE GREASY OIL.

Posts: 789
Joined: Fri Sep 09, 2005 11:04 pm
Location: Omaha, NE

Re: PCV valve or Catch Cans for street performance

Post by My427stang » Thu Jun 18, 2020 8:03 am

If the engine is going to run at part throttle/high vacuum for most of it's life, I love a PCV.

I tend to not do much other than grab one off the shelf, but a 3/8 line seems to be more than what an engine would need and the PCV should slow it down, but I I like the orifice idea, but have never tried it.
70 Mustang, 489 FE, TKO-600, Massflo SEFI, 4.11s
71 F100 SB 4x4, 461 FE, 4 speed, port injected EFI, 3.50s

Posts: 1139
Joined: Fri Jun 30, 2006 9:37 am

Re: PCV valve or Catch Cans for street performance

Post by stealth » Fri Jun 19, 2020 9:14 pm

Unless you can get rid of all the oil and vapor, be prepared to be horrified by the carbon build up on backside of intake valves...
The reasonable man adapts himself to the world; the unreasonable one persists in trying to adapt the world to himself. Therefore, all progress depends on the unreasonable man.

Posts: 467
Joined: Sat Jul 27, 2013 7:14 pm

Re: PCV valve or Catch Cans for street performance

Post by dfarr67 » Mon Jun 22, 2020 5:30 pm

I discovered oil in the TPI plenum, I ended up ordering that very expensive Wagner PCV valve and tuned it as they have in their instructions no more than that, I have Corvette magnesium valve covers and I stuffed the baffle with stainless steel wool, finally found a used Saiko Michi catch can. Checked tha catch can today and it was dry- I would say the new PCV valve is doing it's job.

Posts: 1859
Joined: Sun Oct 07, 2007 11:59 pm
Location: Galt's Gulch

Re: PCV valve or Catch Cans for street performance

Post by enigma57 » Wed Jun 24, 2020 11:55 pm

BobbyB wrote:
Tue Jun 16, 2020 11:17 am
I just recently eliminated my PCV in favor of a road draft tube. I will probably run the oil for the summer and send it off for analysis (maybe 1500 to 2000 miles).

I tried a cyclone separator and caught a little oil, but not as much as I was consuming. I am now convinced all the oil my engine was using was through the PCV system. I tried a .094" fixed orifice PCV valve and it seemed to do a little better than the only other factory pvc valve I tried. I didn't run the fixed orifice very long......
We run carburettors so that's what I do as well, Bobby. An intermittent and uncontrolled vacuum leak (AKA PCV valve) is the last thing I want. Makes it impossible to get the carb(s) tuned right on the money. Will retrofit a road draught tube and baffle to my late '60s 292 Chevy inline 6 engine along with 3 well baffled circle track valve cover breathers up top. Running an electric fuel pump, so will make a plate to cover the fuel pump hole and weld a '40s - '50s Chevy stovebolt 6 road draft tube to the plate.

Son's 350 Camaro engine will be a little different. Its a '96 Vortec block with AFR heads and a late model Edelbrock intake, so no provision for an early year factory block mounted baffle under the intake manifold and factory road draught tube. I have devised a way to fit one if need be, but decided to keep things simple. Found some well made circle track valve covers with 2 well baffled breathers on 1 cover. Bought 2 sets and will run 2 breathers on each valve cover, 4 breathers in all. The remaining 2 valve covers (none having any breathers nor holes), I'll sell eventually to someone who either wants a nice set of polished aluminum covers without holes...... Or if they want holes, they can add them where they want them. Will probably drill a hole in his new intake and retrofit an early year oil filler tube and factory style breather there as well. The circle track breathers on his valve covers clamp onto baffled risers. Adding an old style oil filler tube and factory style push on breather/filler cap will add venting to the lifter valley and make adding oil easier as well.

Both of these engines will be in road cars and will only be run hard from time to time to work out tuning (although the 292 inline 6 will pull a trailer in the hill country from time to time). :D

Happy Motoring,


Post Reply