The Stovebolt Site Forums The Shop Area Engine Shop Adding a PCV to a 60's engine with non-PCV valve covers.

I have seen the Tech Tip where people have made modifications to the back of a stock style valve cover to add a port for a PCV valve on a SBC. That may work fine for some people, but I didn't want to modify an old stock cover if I don't have to. The originals are out there, but why mess them up if you don't have to. So I came up with a different method.

This will only work if you block still has the hole at the rear of the block for the Road Draft Tube and the hole in the intake manifold for the Oil Filler Tube. I have a '67 327 and it has both of these holes, but they are both blocked off with what looks like expansion plugs. Inside the lifter valley it will have a canister style baffle. (see photo RoadDraftHole.jpg)

Pull both expansion plugs and replace the front one with the Oil Filler Tube and breather cap. Make sure that it is a breather style with filter and no PVC port. (see photo OilFillTube_and_Breather.jpg) That's the easy part.

Since I am limited on the number of photos I can attach, I am placing the next set of photos in the message below this one.

The rear plug is a bit trickier and you will need access to some large drill bits or a small mill. Using the plug you removed from the Road Draft Tube hole, or a new one of the same size, drill/mill out a 15/16" hole in the center of it. (see photo RoadDraftPlug.jpg) My milling wasn't perfect, but will work for this.

Install a standard size PCV grommet in the hole (see photo PCV_Grommet.jpg) you just created into the plug. (see photo PCV_Grommet_Plug.jpg) you may need to trim the outside diameter of the grommet slightly.

This can now be installed into the Road Draft Tube hole at the back of the block. I don't have a photo for this yet since my block is still at the machine shop, but I have a photo of the completed assembly showing the PCV valve in the newly created port. (see photo PCV_Assembly.jpg)

After installing the assembly in the rear of the block, the PCV valve can be plumbed into the back of the carb, one of the vacuum ports on the intake manifold, or into the air cleaner. Your choice, as long as it has a vacuum source to run the PCV.

I don't know if this will help a lot of people or not. I'm not sure how many engines still had the road draft tube hole and oil filler tube holes plugged from the factory. It just seemed to be a cleaner way to do the installation. I am trying to make my '67 327 look as close to an old early model 283 as I can so that it doesn't scream "New Engine" in my '62 C10.

Additional photos for PCV installation

Why not just use the factory adapter fitting that bolts onto the block in place of the road draft tube and an inline-style PCV valve that plugs into rubber tubing on both ends? I installed hundreds of them at my shop in the Atwater/Merced area in the mid-1970's when California mandated that all vehicles had to be retro-fitted for "closed" PCV systems.
Jerry

Jerry,

I didn't know there was one. That's why I came up with what I did.

It was a very simple modification- - - -unbolt the road draft tube, and bolt in a cone-shaped adapter with a 3/8" tubing nipple on it. Then run a piece of rubber vacuum line forward beside the valve cover toward the carburetor and install a PCV valve with tubing nipples on both ends. Remove the pipe plug at the rear of the carburetor and install another 3/8 tube nipple and a second piece of hose, or install a T fitting in the power brake hose to draw the vapors into the intake. The final part of the conversion was a sealed oil filler cap with a hose nipple on it, and a fitting that was installed on the underside of the air cleaner housing to draw air from the "clean" side of the filter element to complete the closed loop system. There were some stiff fines handed out to people who refused to complete the conversion, assisted by roadside spot checks done by the same CHP enforcement goons who harassed truckers about too much Diesel exhaust smoke. Car dealer parts departments and auto parts stores sold the whole setup as a kit, and untold hundreds of thousands, maybe millions of them were sold. The "California Air Resources Board" (Yep, C.A.R.B.!) was a very unpopular bunch of bureaucrats back then!
Jerry

I remember when the whole smog crap and checks started out here. I was still a teen back then and driving my '63 at the time. It was supposed to be smogged the first year except that I had the wrong VIN. My truck was on the off year, at which point it wasn't require because of the age. So I never had to actually smog my old truck.

I had to smog my '62 when I bought it (transfer of ownership) but not since then. I like the concept of PCV, it's good for the engine, but wanted the old look.

I have a unused vacuum port on the rear of the carb baseplate. I will probably plumb what I have into that. I will use my new fitting since I already built it. I think it will look fairly clean. PCV valve will be easy to change if needed. Plug and play just like in the valve cover, just a little farther back on the engine.

C.A.R.B. is still an unpopular government agency out here. I have some horror stories I could share.

62 Stick -

My '54 had parts of a California PCV system on the engine when I bought it. The air cleaner didn't have a hole cut in it for a hose. The angled rubber fitting on the top-rear of the valve cover was pushed into a crude hole. The vent slots on the valve cover were sealed. A question on Stovebolt and got this response from CrankyOldDude. Fun history lesson.
https://www.stovebolt.com/ubbthreads/ubbthreads.php/topics/715284/1.html

- Lonnie

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(written by "CrankyOldDude",

That is pieces of the AC (AC spark plug of General Motors Corporation) “California State Approved” crankcase ventilation system. California required most 1950 and later cars and trucks to be retrofitted with a PVC system when a used vehicle was sold. The program originally started from January 1, 1964 and ran through January 1, 1966.

The installation required two kits, CV3 and KV1002. CV3 consisted of an intake manifold fitting, 3/8 hose, CV609 PCV valve, hose clamps and fitting to the valve cover for an open PVC system. KV1002 closed the system, it consisted of 5/8 inch hose fittings, 5/8 hose to connect air cleaner to the valve cover for clean air induction, sealed oil fill cap and a plug to close up the hole after the road draft tube was removed. The slots on the valve cover were soldered closed.

I believe your PCV valve is a CV693C. If so, it is installed backwards so the flow is backwards. CV693C is designed to mount on the ventilator for the factory installed PVC system on 261 engines as well as California 1960-62 235 engines.

If you want to keep this setup, I would recommend finding a CV609 valve. I would reconnect the open hole on your valve cover with a 5/8 hose to your air cleaner. The CV609 valve is spliced into the hose that connects the valve cover to the manifold fitting. You will need to find some hose fittings, hoses and a CV609 PCV valve.

Thank you for all the replies and especially the link to the older thread.

Looks like the setup I created mimics the original intent of the California retrofit kit pretty close. I just placed the PCV a little farther back in the system. The PCV valve I have is designed to allow airflow from the metal end toward the plastic (hose) end, while blocking airflow in the opposite direction in the event of a backfire through the carb. I believe this is the correct direction of airflow for my application.

The airflow in my set up is outside air is drawn into the engine via the breather on the Oil Filler Tube, passes through the filter in the cap, is drawn through the lifter valley and exits the block through the road draft tube hole. There it goes through the PCV and goes back into the intake manifold via a vacuum port on the back of the carb baseplate.

As was stated in the linked thread, figuring out what previous owners did is a lot of the fun of these old trucks.

Edit: I checked the PCV valve I have. Numbers on the side are 2072. I can suck on the hose end and air flows. I can blow into the hose end and air is blocked.

I am posting this on an old thread just to keep the info in one less place

I installed a PCV system on my ‘46 w/ ‘54 235, it was a few hours work once I had all the material. It a reversible process as I sourced new critical parts instead of modifying existing pieces…
Used a oil fill tube and cap from a ‘63 corvette ( bought new at Eckler), pulled the existing draft tube out and hammered in the new tube w/ loctite, drilled the air cleaner and installed a grommet (I run a paper element), installed a new oil fill cap in the valve cover (Napa thm 7031691) which came with 2 rubber bushings, JB welded the valve cover slots, put a tee in the intake manifold vacuum port and ran 3/8 copper tubing from PCV valve. Taped over the oil fill hole and vacuum tested at the dipstick, 3”hg, seems on spec to me on a relatively fresh engine…. Used ACDelco PCV 19310783 see attached pix

I don’t have a pic handy. Mine is kinda the same, but backwards. Similar breather in the oil fill, but that’s where my PCV sits. It’s a 90 degree PCV plumbed over to the intake to get its vacuum.

Make-up air is via a motorcycle style, clamp-on, breather affixed to bottom of the road draft tube.

Seems to work fine. Catches the blow by and doesn’t seem to suck oil.