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LS3 PCV / Catch Can Routing for Holley Valve Covers and LS3 Vented PCV Valley Cover?

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Old 05-23-2020, 07:39 PM
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Default LS3 PCV / Catch Can Routing for Holley Valve Covers and LS3 Vented PCV Valley Cover?

Hey all, I have a 416 LS3 in a 77 C10 pickup using Holley valve covers and a C6 vette (manual trans) vented valley cover, and L92 truck intake.

How would y'all route the PCV setup? I've welded a 3/8" barb to the intake tube, which currently runs to the passenger side valve cover. For the dirty side, I have two options:

Driver's side rear port to intake (or through catch can)
Valley cover to intake (or through catch can)

Old 05-23-2020, 07:58 PM
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I would pull from the intake (Catch can if needed) and connect both valve covers to the clean side.
Old 05-23-2020, 08:08 PM
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Originally Posted by LLLosingit
I would pull from the intake (Catch can if needed) and connect both valve covers to the clean side.
So intake to valley cover (through catch can), and both valve covers to intake tube?
Old 05-23-2020, 11:51 PM
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Yes, Fresh filtered air in both valve.covers, Dirty air from valley cover to catch can, Catch can to vacuum source Not sure how your valve covers are setup but you can run one line to a T feeding both valve.covers.
Old 05-24-2020, 11:36 AM
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Originally Posted by LLLosingit
Yes, Fresh filtered air in both valve.covers, Dirty air from valley cover to catch can, Catch can to vacuum source Not sure how your valve covers are setup but you can run one line to a T feeding both valve.covers.
I'll give that a whirl. I have the LS3 (manual trans) valley cover so I might as well use it.
Old 05-25-2020, 09:06 AM
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You have to be aware of one thing (ask me how I know.... LOL)…… The GM valve covers have restricted passages (.115 dia) in the hose connection ports...…This restricts the amount of vacuum that is allowed to suck the oil vapors out of the crankcase...…. The aftermarket valve covers don't have these......When I did mine not understanding what was happening with the extra vacuum..... It ended up that very shortly after driving the car it started smoking like crazy...… Hummm!!!...… I checked the catch can and it was full to the top with oil which was sucked into the intake and burnt...…. what I did to resolve the issue was to make a inline restrictor with a .115 dia hole in it to control the amount of vacuum allowed to suck the vapors...…. I put it in the feed line from the catch can to the intake port connection...… Problem gone...…

Ken
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Old 05-25-2020, 02:31 PM
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Originally Posted by kwhizz
You have to be aware of one thing (ask me how I know.... LOL)…… The GM valve covers have restricted passages (.115 dia) in the hose connection ports...…This restricts the amount of vacuum that is allowed to suck the oil vapors out of the crankcase...…. The aftermarket valve covers don't have these......When I did mine not understanding what was happening with the extra vacuum..... It ended up that very shortly after driving the car it started smoking like crazy...… Hummm!!!...… I checked the catch can and it was full to the top with oil which was sucked into the intake and burnt...…. what I did to resolve the issue was to make a inline restrictor with a .115 dia hole in it to control the amount of vacuum allowed to suck the vapors...…. I put it in the feed line from the catch can to the intake port connection...… Problem gone...…

Ken
i know the drivers side has a restricted orifice but not the passenger side?
Old 05-25-2020, 02:39 PM
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Originally Posted by kwhizz
You have to be aware of one thing (ask me how I know.... LOL)…… The GM valve covers have restricted passages (.115 dia) in the hose connection ports...…This restricts the amount of vacuum that is allowed to suck the oil vapors out of the crankcase...…. The aftermarket valve covers don't have these......When I did mine not understanding what was happening with the extra vacuum..... It ended up that very shortly after driving the car it started smoking like crazy...… Hummm!!!...… I checked the catch can and it was full to the top with oil which was sucked into the intake and burnt...…. what I did to resolve the issue was to make a inline restrictor with a .115 dia hole in it to control the amount of vacuum allowed to suck the vapors...…. I put it in the feed line from the catch can to the intake port connection...… Problem gone...…

Ken
Can you elaborate on how you made a restrictor?
Old 05-25-2020, 02:56 PM
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Originally Posted by showdog75
Can you elaborate on how you made a restrictor?
You can run a $5 Beck Arnley or Fram in-line pcv valve from O’Reilly. The part number is actually listed in the Holley instructions.
Old 05-25-2020, 03:14 PM
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I took a aluminum round and turned hose barbs on both ends and drilled the restriction hole thru it...…

Old 05-25-2020, 06:49 PM
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Originally Posted by kwhizz
I took a aluminum round and turned hose barbs on both ends and drilled the restriction hole thru it...…

That's what I'm talking about. Why buy something when you can roll your own. Nice work
Old 05-25-2020, 10:53 PM
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Originally Posted by showdog75
That's what I'm talking about. Why buy something when you can roll your own. Nice work
I can dig that for sure, but for $5 in case anyone is wondering here is the Beck Arnley valve as recommended by Holley:

https://www.summitracing.com/parts/b...SABEgLNbvD_BwE

Old 05-26-2020, 05:35 AM
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If Holley recommends that part I would use it...…… They are the best !!!!… I didn't know about that when I did mine...… Maybe if I would read the instructions...…..LOL...



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