Valve Cover Breathers and Catch Can

dcozzi

Veteran Member
May 1, 2002
4,442
Phoenix, AZ
Does anyone know where to get a screw in adapter for a valve cover so I can run a hose to a catch can?
It is an M/T finned type "old school" valve cover and I need it for the oil fill side. I am bringing both sides to a catch can. I can gut a PCV valve for one side, but I need a good sealing screw in type for the oil filler cap side.
The catch can may just get home made. I need some TIG practice anyway.
 

biker

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Gold Member
Dec 7, 2014
4,689
Canada
As far as the usual catch can principle goes, you dont need it routed to both covers. It just tees in with the existing pcv hose before it goes back to the vacuum source at the intake.
PCV (with or without catch can) only works properly if it draws filtered air through the engine from one side, through the pcv on the other side and into the vacuum source.
With mine, I have a filter on the oil filler plug on one side (draws fresh air in), and the catch can teed into the vac line between the pcv and manifold.
Unless of course I'm totally missing what you are trying to say. (Very likely). In which case, apologies in advance!
 

Lowend

Administrator. .a car, a man, a maraca.
Staff member
Lifetime Gold Member
Mar 25, 1999
16,738
San Jose, CA, USA
"Positive Locking" is the term
like so
https://www.summitracing.com/parts/...5MRQfF93gaRO_Ai0Zu7CKGJ9DDU1tqYxoCHBgQAvD_BwE

M141802478.jpg
 

CorkyE

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Lifetime Gold Member
Nov 4, 2004
11,639
Ringgold, GA
I have mine set up the same way as Biker. You really don't need any complex fittings on a low vacuum setup, like the pcv. The vacuum itself is enough to seal. I've been playing with restricting the inlet side, just to see if I can get more vacuum through the engine. I don't have any data that says this will work, but I haven't noticed any bad effects.
 

krabben1

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Lifetime Gold Member
May 16, 2007
8,399
( . Y . )Delco
Im running a moroso air/oil seperator between my PCV valve and efi on both my BBs,but it really only gets used on my gen6 454.Regular breather on the pass side,pcv valve in the drivers.
 

biker

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Gold Member
Dec 7, 2014
4,689
Canada
I have mine set up the same way as Biker. You really don't need any complex fittings on a low vacuum setup, like the pcv. The vacuum itself is enough to seal. I've been playing with restricting the inlet side, just to see if I can get more vacuum through the engine. I don't have any data that says this will work, but I haven't noticed any bad effects.
Yes. As for sealing, I just added an O-ring to the pcv grommet as it was fitting a bit looser than I would like.
 

COPO

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Lifetime Gold Member
Sep 15, 1999
21,607
Ontario, Canada
My homemade catch can from a Seafoam can. 2 barb, fittings, rubber hoses, male to male hose joiner, 1 SS large scouring pad, and cooper water pipe drilled with holes, a drain cock and JB Weld. Top fitting is with the copper pipe. SS pad sits on the bottom and the lower hose pics up clean air for the intake where the orig PCV hose went on the Holley.

50F3C3C4-5FDC-41BF-9566-7F467AFE8438.jpeg
 

biker

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Gold Member
Dec 7, 2014
4,689
Canada
Great looking engine bay! Well done. With your pcv setup, what is the purpose of the extra line going from the catch can to the air filter base? I would think that any vacuum applied to the can would simply vent through the air cleaner base and not apply any vacuum to the pcv?
 




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