Technical What would Johnny hamber do?

would you drill and tap this intake for a pcv valve or just run a road draft tube?

 

Well, a pcv is certainly the better way to go but, on a fresh engine it should not be sucking much foul air. The advantage is that it will provide a negative pressure atmosphere and that is helpful in keeping things clean and some will suggest that it can help with ring seal. If you have concerns about 'looks' then you can mount the valve on the bottom of a runner or plumb into a spacer under the carb(s).

 

Is it going on an engine that needs to last 100k miles? or 25k miles?

Is there anything else modern on the build?

In other words, like most things, "it depends"

 

Road draft tube plumbed straight down a dolphin's throat.

 

My concern would be with a PCV plumbed into one carb or one runner, it would be running leaner than the other ones. I suppose you could use several T-fittings and hoses to pull from all carbs/runners equally but it'd look like hell. I'd go with a road draft tube for now.

 

If it was mine, I'd worry more at this point about what air cleaners to put on top of those rock catchers.

 

fresh build, going to start off with this edmunds, a lot less painful to tap into the spacer under the rear carb than a runner on a vintage intake, no matter how well i hide it.



i guess i could run a hose down to the exhaust

 

That looks like the plenum connects all 4 carbs, so it could be drilled and tapped at the rear, or even underneath, out of sight.

 

Johnny say’s No!

I also agree with what Rocky said.

 

If plumbed into the plenum on that manifold a PCV won’t make one carb run leaner than the others in any negligible way.

I think PCVs work really well but if you’re not going to be dailying it and doing 25k a year I wouldn’t go to the effort of drilling a tapping it, in fact I wouldn’t even bother with a road draft tube, just fit a couple of filtered breathers and away you go.

 

Draft tubes look cool with that oily froth at the end tube and oil coming from every seal on the engine splattering on the bottom of the ride and marking its spots along the way.

 

rustproofing

 

You just described a Ford Y-Block

 

that's next on the list waiting to be built, 4-71 with either four 97's or a pair of 400cfm AFB's

 

Oh, that doesn't happen until the engine has a few thousand miles on it....

 

just burn it off in the header?

 

You have to have a vent to allow air in with a PCV valve. I use the road draft tube as the inlet, while the PCV draws the vapor out.

 

Road draught tubes get a bad press. On an old knackered smoky oil burner they puke out.

But a well built freshly built motor with minimum blow by and good oil vapor seperation upstream of the tube they work fine.

They also need a "draught" with the outlet in a low pressure zone under the car to draw out properly, as they are designed stock.

 

oil fill tube in front with a filter/breather cap on it

 

PCV vent?
Isn't that taken care of by the inherent blow-by?

 

you're scaring me

 

A small block Chevy plastic 90 PCV that goes on the valve cover MAY fit under the wire loom covers of the hemi.

 

Duh.. I read "road draft tube" and thought " oil fill tube." I'll go back to sleep now.

 

I did one on a OT tunnel ram. I would NOT on that.

The guys saying plumb to exhaust, there are systems designed to create a pull and use a check valve. Problem is, it must not have ANY restriction - open header with short collector.
https://www.jegs.com/c/Oil-System_Crankcase-Evacuation-System/10449/10002/-1
As you can see, they are basically road draft tubes in the collector.
You may also notice vacuum pumps and catch cans if you want to keep from drilling that intake.

 

hiding the pcv isn't the problem, i put a grommit in the hole for the road draft tube and install it there, but where do i plumb it to?

 

i won't have much past the collector, maybe 24-30 inches and a quick turnout

 

I don't have a game plan on how to plumb it, but I'd want one if it was me. I tried to use the road draft tube on my flathead, and it was no bueno. Oil leaks, smells, stuff that most guys just put up with owning an old engine but not me. I fitted a PVC and all the leaks are gone. Mine was easy, that 4x2? Not so much. Maybe a hidden vacuum pump to suck that block out?

 

Could en electric set up work.
Never used one like that
Just wondering.