'54 235 emissions upgrade?

[Old Crow]

OK, so I'm crusing Ebay looking for a road draft tube to replace the broken one on the '54 I'm doing.
Found a guy who was selling what he claimed was a factory optional tube with a PCV valve in it instead of the road draft tube(for like $150!).
So that got me to thinking(uh-oh!).
Went into the back room and pulled the remainder of the broken tube out of the engine, found a grommet and a PCV valve and:




There's a plugged off hole in the intake where I can put a vacuum nipple and the oil filler cap is already vented. Way less than $150.

Anyone got a reason it won't work?

[wolffcub]

dont think you want to hook it to that port on the intake. Would that not just suck non mixed air all the time into the cylinders? i think you would want it to go to a carb port that is connected to the top of the carb horn.

[wolffcub]

If your carb has no port you can install some sort of nipple to the side or bottom of the air cleaner dish and the flow into the carbs will then pull the fumes from the motor.

[wolffcub]

http://www.jalopyjournal.com/forum/t...cv-tech.61376/

[Old Crow]

All PCV valves are hooked to manifold vacuum, it's just that the port is usually in the base of the carb.
Upon further reflection, I'll have to seal the 4 little louver vents in the top of the valve cover and run a vented filler cap.
Vented filler caps have filter medium in them to filter the air as it enters the engine.

Of course I've just finished painting the valve cover, so that'll be a do-over.

I'll probably find a PCV valve for a six cylinder engine instead of the one I stole out of a small block for the picture.

[wolffcub]

guess i never really factored in the opening changing in the pvc to limit and or change the air flow thru it. Thought of it being always open lol

[wolffcub]

Thoughts???? Im also interested in this pcv upgrade also.

http://www.summitracing.com/int/part...66-b/overview/

[Old Crow]

If you're going to use an aftermarket air cleaner that comes with the elbow you can install in it's base plate, that would work. Just add the elbow to the air cleaner and run a hose between the 2. In fact, I might have one like it laying around, have to check Tuesday.
I'm not sure of the exact air cleaner setup yet, as the owner is talking about dual carbs and a Fenton exhaust, but hasn't made up his mind yet.
I think if he goes with a stock oil bath air cleaner I'll have to use one of those stand alone vented caps.

Just for grins, here's the ebay link for the "factory" draft tube with a PCV valve. You can see he's real proud of it. If you look closely at the valve cover in the pictures, it doesn't have the little vent slots that I mentioned earlier. Confirms what I said about having to block them up. Also the instruction sheet pic shows the vacuum line hooked into the manifold at the spot I'd picked.

http://www.ebay.com/itm/Original-Fac...5a77e4&vxp=mtr

[1project2many]

Well, I've never seen that tube but I may have one of those valves floating around. If I wanted a factory look I'd probably get the thread size, drill the hole, and braze on a fitting to thread the valve into. I think moving the valve outside the tube is a good idea just so it's not getting oil dumped on it during an oil change.

Lotsa neat stuff, although maybe trivial, if you search for "rpo 217 ventilator"

http://vcca.org/forum/ubbthreads.php...th_Air_Cleaner
Photos of a 261 with PCV valve showing ventilation tube to air cleaner. Looks like all 261's came with this system.

http://www.oldchevytrucks.com/blog/i...-must-breathe/
Some detailed photos of valve covers for PCV and road draft systems near the bottom of the page.

And more searching for 261 pcv:
http://www.chevytalk.org/fusionbb/sh...32/tid/279099/
Fun discussion with more OEM drawings

Here's a neat idea although he doesn't remove the valve cover ventilators:
http://speedprint.com/deves50/pcvinstall.php

Photos of PCV system:
http://www.stovebolt.com/ubbthreads/...024#Post782024

[wolffcub]

Would it be beneficial to vent from the valve cover instead of the downdraft tube? Or possible to vent from both ?

[Old Crow]

With the draft tube, fumes and such are only pulled out of the motor as you drive. With the PCV system, engine vacuum draws the fumes out of the motor constantly. Should lessen the sludge buildup in the motor. Also, you won't have that drip of oil on the garage floor under the tube.
All in all, probably not a bad mod, considering we're pushing these motors harder than they were ever designed to be pushed back in the 50's.
After studying the instruction sheet on that Ebay ad, I think I'm going to plumb it with brake line and a couple short pieces of hose instead of using just hose. Depending on carb setup, I may run it around the front of the valve cover like the stock fuel line is routed.

@ 1project: Did you read the Jim Carter link? They apparently lighted the slots in the valve cover when they went from road draft to PCV. I think I'll eliminate them instead of illuminating them.

[1project2many]

@ 1project: Did you read the Jim Carter link? They apparently lighted the slots in the valve cover when they went from road draft to PCV. I think I'll eliminate them instead of illuminating them.

Yes... it made me a brighter man!

There are differences between pcv/ emissions hose and fuel hose although some of the "multi fuel" hoses seem to hold up well in PCV applications.

One of the setups I looked at routed the PCV line around the front. Inliners has several PCV threads.

[mr48chev]

You post show that you know exactly what you are doing and why you do it that way.

The tubes that run to the air cleaner base run to the valve cover so engine draws in filtered air to the crankcase that flows though the crankcase and out the pcv valve. if it doesn't have a filtered or screened breather cap on the valve cover.

It looks like that guy on Ebay was another fisherman looking to hook a sucker using a juicy story line.

[1project2many]

Duplicate post

[whitedog76]

The PCV setup was a factory option for many years. There were even companies that made kits. Of course, you'll need the non-slotted valve covers and vented oil cap to make it work.

Here's what a factory one looked like.

http://67-72chevytrucks.com/vboard/s...d.php?t=641477