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Valve cover question

  • Thread starter Thread starter Stang951
  • Start date Start date Mar 27, 2004

Stang951

Founding Member
Jun 12, 2000
1,129
0
0
New Orleans
Mar 27, 2004
#1
  • Mar 27, 2004
  • #1
I have a set of Motorsport aluminum covers, the tall ones with the red writing. I have a pcv valve in the drivers side cover, and a breather in the other one. The passenger side breather hits the drier and has caused dripping of oil onto the header. Do I really need the breather on the passenger side since I have the pcv valve, or can I get rid of it?
 

Michael Yount

Mustang Master
Apr 10, 2002
9,039
6
79
Charlotte, NC
Mar 27, 2004
#2
  • Mar 27, 2004
  • #2
No you can't get rid of it - when vacuum is pulling air out of the crankcase/valve cover through the pcv, that air has to get into the engine somehow. It comes in through the breather. If you get rid of the breather, under high vacuum conditions, you can actually create enough vacuum in the crankcase that you'll hear squealing sounds from air squeezing past the crank seals. On the other hand, under full throttle when there's no vacuum and lots of crankcase pressure, it has to be able to be vented. If the pcv alone doesn't have enough capacity to vent it (remember, your other breather will be gone if you eliminate it), then it will vent through the weakest link - often the front and/or rear crank seals. Many rear main seals have been replaced only to find that the leak persisted because excessive crankcase pressure was forcing oil out the seals. If you want to get rid of the mess, remove the breather, and instead reconfigure that opening so you can run a hose from it to a vented catch can. The catch can will 'catch' most of the oil, and the breather on the can will deposit it's 'mess' away from the engine - where ever you mount the can. Alternatively, a lot of carbed cars had the other brether hose routed to the air filter so the fumes from it go back into the intake.
 

Stang951

Founding Member
Jun 12, 2000
1,129
0
0
New Orleans
Mar 28, 2004
#3
  • Mar 28, 2004
  • #3
Right now the breather is on the rear of the passenger valve cover. If I plug that hole and drilled the front hole on the valve cover do you think I would see less oil from splash, or do you recommend just using the tank and breather.

If just the tank how would I install that? Do I need a special fitting for the cover to attach a hose too? Never gone this route before.
 

Michael Yount

Mustang Master
Apr 10, 2002
9,039
6
79
Charlotte, NC
Mar 28, 2004
#4
  • Mar 28, 2004
  • #4
Not sure, but I doubt there'd be less splash from rear to front on the cover. Yep - you'll need some sort of fitting that goes in the valve cover, and has a nipple (preferably at least 5/16" - bigger provides more venting) for a tubing connection. Arranging catch cans is done differently by everyone - so it's a fabrication issue, but an easy one. Shoot me an email at myount@senndelaney.com and I'll send you a pic of my arrangement. It's a sealed pcv system with efi, but the concept is similar. It'll give you ideas how to mount yours if you decide to go that way.
 
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