Hot Rods Pcv valve placement.

Before anyone goes on a rant and says use the search bar, I did. So if there's a thread that answers my question, my mistake.

My question is, I have a vacuum port on my intake behind the carb. Is this vacuum port just in an intake runner or does it go all the way to the valley to be sufficient place for a pcv valve. What about the port on the back of the carb? Or would I have to drill the intake down by the distributor somewhere in the last pic. Motor is a small block 350. Here's some pics.

Thanks

 

I'm pretty sure you need to access the area near the dizzy. you need crankcase gasses not runner air

 

Both ports you are showing is a vacuum port. I usually plug into the carb for the PCV since what it is doing is pulling out Crank Case gasses. That is what the PCV is for. When the engine is running it builds pressure in the crank case and at higher RPMs it builds more. I have ran numerous cars with out PCV installed just valve cover breathers and at high RPMs blew them off...lol.

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The pis you show are for the PCV hose(one end).. The PCV itself can go to the valve cover or you can drill a hole in the intake(that goes to the valley).. If the latter is chosen, make sure to use a grommet that doesn't allow oil to enter, just fumes...

 

Looks like booster is running to carb base. I'd use the port shown for that, and run pcv hose to carb port.
Some longer carb studs wouldn't go amiss.

 

are you wanting to run old valve covers with no holes? if you mount the pcv in the intake make sure to fab up a baffle or you will suck a lot of oil. i've seen guys drill into the block behind the intake also.

 

Yes Scotty. Trying not to pull the intake to drill one hole lol

 

pull it

 

Your question is confusing. From your OP I thought you were looking for a vacuum source to run a hose to from the pcv valve mounted in a valve cover. But after reading the replies it looks like your looking for a place on the intake manifold to place the pcv valve where it will reach the valley. Well if that port you asked about is pulling vacuum, then it would not be a source of crankcase pressure now would it?

 

Thats what i am trying to verify. Looks like i will have to drill my valve covers. I really dont want to pull my intake off.

 

The pic of the brass fitting will be a vacuum port and so is the hose at the base of the carb. I miss understood what you asking.

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For about $25 with free shipping you can order brand new valve covers already with the holes from Amazon. And while you're at it, order new vac hoses for the booster and pcv, and longer studs to accommodate your carb spacer. The nuts look like they're catching half a thread. 8^)

Jack E/NJ

 

I have early vet valve covers. I didn't want to drill them. After doing some repairs on my Silverado. I found out gm went to a fixed oriface pcv on the 5.7. It has a
.10 hole in it. So it got me thinking. I ended up drilling a .10 hole in my manifold under the carb into the vally.

 

PCV valves will close in the case of a back fire, preventing the flame from reaching the crankcase gases which can be volatile, especially if there is any fuel dilution of the oil. Your method doesn't offer that.

 

Possibly. That was the intention of the original design. But gm didn't seem concerned about it with the new design. The service guide said the new design was fixed and would reduce oil consumption and improve ventilation. My truck seems to like it. My 36 runs like a champ. I really don't think there is much of a risk with a back fire. Plus I like to live on the edge alittle.

 

I drilled a hole in front of the dizzy on an Edelbrock rpm for a SBC. I too didn't want to deflower my finned Corvette valve covers. I used a valve cover grommet in the hole and also JB welded a thin baffle below it. (an old HAMB alliance tag actually) The hose runs to the front of the carb. The fill tube in the intake acts as an intake.

 

Ah, the old Hokey Ass Manifold Baffle trick.

 

Well, I really didnt want to pull the intake, so i bit the bullet and drilled a valve cover. Put the pcv in the back side facing the firewall. I notice it's there but hopefully it blends in. Forgot to take any pics, so if anyone really wants to see it, ill take some this weekend when the trucks down from the lift.

 

pics or it didn't happen

 

Maybe if you'd stop by more than once a year.

I'll take and post some pics probably this weekend.

 

Here's some pictures.

 

You may need some sort of baffle inside the valve cover to keep oil from being pulled through the pcv.

These may work.



http://www.hotrodpartssupply.com/co...replacement-baffles-for-aluminum-valve-covers

 

Nice resolution, I like it!

 

I thought about the baffles. I tried to keep it up as high as I could. I can always add one later on if I need to. I'm going to run it a little and see how it does

 

looks good! i like the "chevrolet" scipt valve covers

 

That's why I didn't want to drill the tops.