69442

Looking for help - advice on installing a PCV into my Edelbrock O4B aluminum intake manifold for an O.A.I. set-up. I know the original W-30 intake manifold had a fitting just behind the water oultet. Can this fitting be added by drilling and tapping the manifold? I assume there will need to be some type of baffle installed under the PCV fitting to prevent oil consumption. Any pictures would be great! Thanks.

Olds64

Why would you drill the manifold to add PCV to an engine? The PCV valve goes into one of the valve cover openings and the opposite end goes to manifold vacuum. Pretty simple. If you don't have a vacuum elbow on the intake manifold then just run it to the base plate of your carburetor.

joe_padavano

He's trying to replicate the PCV configuration on the 1970-72 W-30 cars. Those cars (in addition to four speed W-25 big block cars) used a breather in each valve cover that went to the air cleaner base, with a fitting on the intake that allowed the PCV valve to be connected to the valley of the engine instead of the valve cover. The W-30 intakes and iron four speed intakes had a nipple on the intake in front of the carb. The PCV valve was connected to the base of the carb (for vacuum) and to the fitting on the intake (for inlet) through a molded rubber elbow.

As for modifying an O4B, the fitting obviously needs to be in the thin section between the coolant crossover and the front runners. I don't know if this section is thick enough to tap, as the factory intakes had a boss cast in them for the fitting. Consider welding a bung to the intake for the fitting. Alternately, consider using an aluminum fitting and welding it directly to the intake. The manifold is easy to weld.

dc2x4drvr

Actually I have been thinking about doing the same thing, the nipple in the cast iron manifold is a press fit, and I am going to just drill the appropriate size hole and press in a fitting. Give me a day or two and i can post a pic, and the O.D. of an original fitting.

70Post

Here are some that I made awhile back for an O4B alum intake I am prepping for use ...actually provides a better seal inside the rubber elbow VS. the factory steel nipple that has a very limited contact area inside the rubber elbow. Same OD as the factory piece but the flared area is different.

>Yes...you can drill a hole through the manifold in a similar location..behind the water neck mounting area but towards the P side of the car slightly...close to the front "wall" of the intake runner that's there.

>The best thing to do would be run a complete metal valley pan...either the factory "turkey tray" or a modified factory turkey tray or an aftermarket pan. You are right, you DON'T want to leave the hole exposed to the intake valley with nothing in between...you WILL consume a lot of oil potentially (a friend made this mistake on a Buick GS 350..the factory PCV valve location is through the intake behind the carb a couple inches on that car...used a massive amount of oil).

Olds64

Interesting.

69442

Thank you all very much for the for the input.

dc2xdrvr, I would definately appreciate some pictures when you can post them.

70Post, do you want to sell one of those nipples that you made? Do you think that just using the factory "turkey tray" will be a good enough baffle? Is that all that the W-30 cars used?

dc2x4drvr

Here's a blurry pic of an original PCV Nipple, slightly less than a 1/2" dia.x 1.489"L. Yah the rubber 90* fits loose on this nipple.

Run to Rund

I imagine the manifold is about 1/4" thick so you could drill and tap 1/4 pipe for a fitting. If when you drill it 7/16" for the tapping process you find it is too thin, you could then go to the press in fitting plan.

joe_padavano

That was my point previously. The factory installation has a fairly thick boss cast into the intake for the purpose of supporting this nipple. If one is simply drilling into the area between the coolant crossover and the runners, it is likely too thin to support a fitting. That's why I suggested welding.

dc2x4drvr

The boss is 3/4" thick and the nipple is driven in 1/4"....

70Post

On an O4B I was planning on having a boss or "pad" welded onto the intake...basically in the same spot as the factory W-30 Alum Intake.

There isn't any stress to speak of on this part so I think 1/4" is plenty of material to hold the steel nipple...especially if you get a good tight interference fit. If slightly loose then some good epoxy in the hole prior to installing the steel nipple would also firm things up. Also--the steel tubing is nice a stiff..especially at these short lengths.

Remember..there is no weight to speak of on this thing...the rubber elbow is on there and then a horizontally oriented PCV valve and then about 4 inches of rubber hose to the base of the carb fitting.

I'll look into making another "Long" version like you see on the L side of the pic....this is one I made for the O4B. Why is it longer than the factory steel nipples? You have to clear the much taller intake port. You may want one of each...a short and a long one. That way you can decide which one you like. In fact, I would probably cut the long one extra long and let you cut it down to whatever length you like after you mock things up on your intake.

Here's a pic of the alum boss/pad I am going to weld onto my O4B

69442

70Post, Do you have any extra of those aluminum pads that you would be willing to sell also?

70Post

No extras...I should be able to make you one as I made that one. Let me see if I have some more of the alum plate laying around. I can use the one I made to trace out a pattern and go to work on it.

Do you want the fancy treatment around the top edge?? That's the "style line" I put in it!

64Rocket

It looks like the O4B is pretty close to install the PCV valve.
I installed the PCV valve in an torker manifold. What I did was drill the manifold, installed a PCV gromet in the front and installed a baffle on the under side. A breather on each valve cover and it works great.

Gene

70Post

Be quiet.....I'm working!!!!


http://www.youtube.com/watch?v=EYlDbv7MqE8

70Post

Live from the 70Post Restorations Metal Masters Workshop....your online, just-in-time, one-off (ok...now there's two of these things but who's counting?), virtual fabrication foundry.............

OK---I know---"Don't tell me about the labor, just show me the baby!"

70Post

+ This is a "Limited Edition" piece #2 of 2....signed of course...........

69442

70Post, The Aluminum piece looks fine as is without the fancy groove. It does look tight in that area where the boss will have to be welded. Do you know of anyone who has actually drilled in that spot? I checked with my engine builder, he said that the "turkey tray" gasket should be enough of a baffle, as there is not much oil above the gasket. I will send you a P.M. about the parts. Thanks.

70Post

I filed a couple "curves" into it on a couple spots to help it fit up against the front wall of the intake port as well as the thermostat pad.

Ultimately, whoever welds it may want to do some final "fitting and filing"...they may want to "V" some of the edges for better weld penetration, etc...that depends on the person doing the welding and how they weld.

The turkey tray should be fine, as you stated. The guy I mentioned with the Buick FORGOT to install a turkey tray or valley pan...he was using composite gaskets on the intake and his engine "builder", for some reason, forgot it. They installed a turkey tray and the problem was solved.

I'll pm you with details.

Thanks

69ho aurora

If you do go with the turkey tray ala the factory set up, the factory manifolds didn't have any extra baffling so they though it was ok without anything extra...

69442

I am on the fence about actually drilling this hole. I was hoping that somebody had already done this and had success. I have a NOS O4B and I really hate to ruin it if there is not enough room between the runner and water jacket. It looks really tight in the area where I need to drill. Definately not as much room as with a stock cast iron manifold or a Torker. Any other thoughts??

70Post

All I can say is flip the thing and look underneath...there's PLENTY of room underneath between the front intake runner and the water passage. Plenty of room on top also. That area is flat and solid...if you think you are going to hit water or the intake runner you need to take a closer look...the walls dilineate where the intake runner is and the water passage is. Outside of those you have solid aluminum (ie the floor of the intake).

You are talking about a 1/2" hole (at the most).

How can you mess it up??