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PVC valve
In the dumb question category I am sure ...
Where does one properly route a PVC valve on a SBF valve cover to an eight-stack induction system?
Thx!
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If it was mine I wouldn't run a PCV. I'd put breathers in the valve covers. Or a catch can on the firewall and plumb it to fittings on the valve covers.
I run breathers with my carb motor. Has worked well.
Jim
2016 Mk4 Challenge Car, IRS, 3.31 Torsen, RDI Aluminum 427w, AFR 225s, Vic Jr. ProSystems 780 HP, TKO-600 w/Liberty mods. Forward cage. Levy 6/4 piston Wilwoods. Not completed yet, will be a streetable track car.
2004 Superformance MkIII #1855, 2007 Superformance MkIII #2584 purchased in 2012 both sold.
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Senior Member
PCV on one cover is connected to the manifold vacuum of the carb under the throttle blades. The other valve cover has either an air filter looking breather or a fitting connected to the air cleaner for fresh air. I put an oil catch can between my PCV and the carb to avoid too much oil gumming up my valves.
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Senior Member
it's going to depend on what state you live in. In the beautiful state of Commiefornia, I was required to build a box to encapsulate all eight stacks, and the cap from the valve cover that did not go through the PCV had to go to the box. The other valve cover with the PCV I had to put a non-breathing cap. The hose from the PCV goes to an air/oil separator, and then continues to a port in the intake manifold. The box that I spent hundreds of dollars on now rests on a shelf in my shop. I now run the hose from the non PCV cap to the trumpet on, I believe, the number eight stack. Haven't seen an issue yet, but only a few hundred miles on it since completion.
20220209_164800 by Rick Paul, on Flickr
20220209_164750 by Rick Paul, on Flickr
20210615_100941 by Rick Paul, on Flickr
Rick
Mk4 with Mr. Bruce FIA body, 331 w/ Speedmaster Stack Injection, Full Width Roll Bar with high brake lights by i.e.427, IRS, ABS, PS, PB, FAST FI, First start 3/30/20, First go-kart 7/5/20, paint by Ken Pike
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It’s a trick with an 8 stack. You have to run the PCV in the valve cover to a vacuum port in the intake manifold. Unless you purchased one specifically for this purpose or are willing to tap you own intake manifold, you probably don’t have this port. Some have made a complex spider of tubes from each carb to a common vacuum outlet. There are pics on the forum if you search it. The other valve cover needs to feed filtered air from above the intake. In CA this requires a cover over all 8 intakes as seen in EZ$’s pics.
Are you running carbs or FI? In CA? Let’s just say it’s hard to do. Most would say don’t if you don’t have to. I’m in CA and got my SB100 smog exemption with a PCV system on a plain ol’ Holley 4 barrel. I got my plates and BAR sticker. Unless I’m reading the law incorrectly, I can put whatever intake I want on it now.
Drew
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Originally Posted by
drewr
Unless I’m reading the law incorrectly, I can put whatever intake I want on it now.
Drew
No, you're reading the law correctly. There are no further inspections on SB100 cars after they are titled and registered.
Originally Posted by
EZ$
In the beautiful state of Commiefornia, I was required to build a box to encapsulate all eight stacks...
No you weren't. You were required to understand the law. You could have put a regular intake and carb on for registration and then put your stack intake on afterwards.
MkIV Roadster build: Gen 2 Coyote, IRS, TKO600. Ordered 10/24/18. Delivered 1/29/19. Engine installed 8/8/21. First start 9/12/21. First go-kart 9/17/21. Off to paint 4/11/22. Back from paint 12/30/22.
Build thread here.
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JohnK is correct here. In California, you can do whatever you want after the BAR (Bureau of Automotive Repair) inspection is passed with your sticker. Take that box off and show your off beautiful stacks!!! The stacks are tricky and I have a friend contemplating what to do, but find a used intake and carb to pass and change it all out.
Ted
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Thanks all for the responses.
I was asking as I have a breather / oil fill cap on one valve cover, and a poppet valve (I believe) on the other cover, from which I have just run a hose to the back firewall. The stock Blueprint Engines setup.
What I find is that I have of oil vapor exiting the breather, with over time puts a nice gloss on my valve cover and results in a drip below the bell housing. I am guessing that manifold vacuum, i.e.: connecting that hose to the induction system would get things flowing the right way. The vent allows air in, the valve allows oily air out, and this gets processed on the wrong side of piston rings.
I don't have any manifold ports available on the Inglese EFI 8-stack. Looks like I may just let the beast mark it's spot ...
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You could just hook both valve covers to an oil catch can with a breather. It will collect all that oil being spilled on your covers. You just empty the catch can every so often.
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Like this:
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Originally Posted by
drewr
It’s a trick with an 8 stack. You have to run the PCV in the valve cover to a vacuum port in the intake manifold. Unless you purchased one specifically for this purpose or are willing to tap you own intake manifold, you probably don’t have this port. Some have made a complex spider of tubes from each carb to a common vacuum outlet. There are pics on the forum if you search it. The other valve cover needs to feed filtered air from above the intake. In CA this requires a cover over all 8 intakes as seen in EZ$’s pics.
Are you running carbs or FI? In CA? Let’s just say it’s hard to do. Most would say don’t if you don’t have to. I’m in CA and got my SB100 smog exemption with a PCV system on a plain ol’ Holley 4 barrel. I got my plates and BAR sticker. Unless I’m reading the law incorrectly, I can put whatever intake I want on it now.
Drew
I am running EFI. I am wondering if I can hijack the IAC air inlet presently occupied by a small air filter (T into it maybe?) IAC is always running at least 20% duty cycle ...
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Originally Posted by
Bob Cowan
Like this:
Yikes! That's a piece of work!
Granted, this is a different manifold than mine. Why does one need to pull vacuum from each intake port?
Thanks for sharing!
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If you only pull from one or intake port, you will get a weak and pulsating signal. Drawing from all 8 gives you a much stronger and consistent signal.
Also remember that in 1965, the crank case was vented to ambient air.
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Not a waxer
Originally Posted by
drewr
You could just hook both valve covers to an oil catch can with a breather. It will collect all that oil being spilled on your covers. You just empty the catch can every so often.
Ain't gonna fly in California. They want a closed system with a PCV plumbed below the throttle blade(s) and a breather drawing filtered air from the air cleaner.
Jeff
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Senior Member
Originally Posted by
LateApex
In the dumb question category I am sure ...
Where does one properly route a PVC valve on a SBF valve cover to an eight-stack induction system?
Thx!
This is a great thread for me as I'm running the same setup as Bob and have seen all sorts of setups with the valve covers. Is the reasoning for all this routing from the valve cover vents an emissions thing? Engine longevity thing? If it's just the fact that some moisture and oil comes out of the vents does the vented catch can route to both valve covers? Presently I just have vented covers.
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