PCV setup
 

I've read most of the PCV threads here. Most seem to hash over the basics well enough, but I have a "too much" situation.

To register 707 in California, I'll have to have a proper PCV setup with a closed crankcase ventilation system. BAR will reject anything else. The car (originally registered in MA) has closed valve covers and a rear breather. It also has a front filler.

Since one valve cover will have to breathe, it means I have to buy a pair of covers with twist-lock holes in them - I will probably go with the cast "COBRA 428" ones from Branda.

That means I have too many damned holes - one in each cover, the filler, and the breather. Since ANY PCV installation is non-original, I want to install something that is both attractive (as far as it can be) and serves the engine's needs as well as BAR's. So I'm thinking about this setup:

• Twist-to-push on converter in each valve cover.
• Push-on closed cap with tube vent on each valve cover tube.
• Emission hose from each VC cap to hardline fitting through the turkey pan into the bottom of the air cleaner. (I'm actually thinking about a T fitting just under the pan on the non-linkage side, both hoses connect to it then vent through the hardline into the air cleaner.)
• PCV valve in breather port, emissions hose to intake fitting.
• Closed filler cap.

(There are twist-on closed VC caps, but they're huge and ugly - hence the two-part solution. Push-on caps are more attractive and more correct for the era.)

Anyone have a better idea? Should I just block off the breather port and put the PCV valve in the other valve cover? That's a little more standard but asymmetrical and ugly (IMHO). I don't mind swapping minor pieces around all day but I'd rather not change out the intake.

I know I could set something else up, simpler, and then put all the present pieces back, nice and original... but I do believe in the value of PCV so I don't mind making it a permanent modification. I just want to do it as right as possible in all ways - functional, smog-passing, visually and even using proper era components. All thoughts welcome.

There doesn't appear to be any rhyme or reason regarding how the BAR will treat this when you visit. This is really a non-issue, since once you have your SB100 numbers, the worst that can happen is another visit to the BAR. I wouldn't make any changes and take it to the BAR as is. Most likely, you'll pass.

Cant you put a PCV fitting in the rear breather tube and run the hose to the air cleaner?

PCV requires the valve, connected to intake vacuum (typically at the base of the carb), plus a breather "on the other side" (wherever that happens to be) - and while an open breather will function, most smog specs say that it has to be plumbed into the air cleaner housing so that fumes will be pulled in and burned.

The problem is that I don't have any way to do a halfway job - with unvented valve covers, there's no place to put a breather and a PCV valve.

I suppose I could just bulldoze the BAR check, but the word is that no one's getting past the PCV requirement in recent months. It apparently used to be more hit and miss.

How about a closed breather fitted to the oil filler tube and plumbed to the base of the air cleaner assy, in conjunction with PCV in one valve cover going to base of carb.

I made my own system. Have the Branda twist valve covers, so bought two small twist caps and fitted 90 deg fittings to the center of each. I run a hose from those to a "T" fitting and from there to a PCV screwed into the intake manifold. I use a tall block vent on the hole at the rear of the manifold.

Before I did this, I would get a build-up of yellow glop under the valve cover caps. Moisture and additives from the oil I think. It wold even back up out of the vent. No more probalems now.

ps: don't get the Branda 428 cast covers if your car has side emblems that say 427. You'll get tired of answering questions. I have the 428 covers and I'm going to change to the ones that say "Cobra LeMans"

I have a new set (in the box, never run) of these I'll sell for $125.

http://www.carrollshelbyent.com/engine_valve_covers.cfm

After I got them, I decided to go with the polished version of the same valve covers.

Rodger

Ford racing makes a closed push on breather cap with a nipple for a hose to the air cleaner. Part # M-6766-G302. It's available from Summit for $7.25. I'm pretty sure it is made to fit the filler tube on the intake manifold. I'm running a similar, but open breather # M-6766-B302
That and the pcv and hose to the carb base should be what you need. No need to change the smooth valve covers.

I'm leaning to the cast covers for looks, anyway - but not soon, if I don't have to. I think the rear PCV and a closed, vented breather on the filler might be the best setup.

Speaking purely in terms of efficiency and operation, does PCV that pulls only through the lifter valley do as good a job as a full cross-venting from valve cover to valve cover? I'm finding conflicting information. Someone above said the valve cover venting is purely automaker convenience and I've heard that elsewhere as well.

It's also unclear whether PCV requires carb vacuum or intake vacuum. Most OEM setups go to the base of the carb, which has a slightly different vacuum profile than the intake. However, my intake has a nice plugged port right below the carb... I could make the PCV valve plumbing damn near invisible.

Among other things, moisture rises when heated. That's why I have both valve covers connected to the PCV. I would suspect that a vent on one cover and the PCV connection on the other for crossflow would be a second best choice.

OTOH, it's not like engines produce a ton of vapor in the crankcase. The difference between no ventilation and minimal assisted ventilation is probably many times that of any "more efficient" system. By letting the PCV pull gently at the internal fumes, I'd bet that some very large proportion of the water vapor is removed.

Now that I look, I see where I can very easily plumb the PCV valve in place of the rear breather and a vented filler cap to the air cleaner, with hardly any permanent modifications. The carb does indeed have a PCV port as well - so I have a nice, easy way to accomplish the job and then see if BAR agrees...

If you have PCV 's in both ,you could run the risk of creating too much vacuum in the crankcase and actually start sucking oil into the intake. The simpler the better!
.....

I don't believe more than one PCV valve is recommended. One valve controlling the vacuum and outflow, and then one or two breathers for inflow. It would be really simple if those breathers didn't need to be vented into the air cleaner to trap back-flow fumes. (As many have nointed out, that's only a smog control feature and has nothing to do with properly venting the crankcase.)

Do you only have to have the closed system for a one-time-only inspection?

AFAIK. It has to be a proper PCV system for smog control (they don't care about crankcase venting; they just don't want the fumes in the atmosphere.) You could take the whole thing off, or go to an open system, after the BAR check.

There's no downside to the closed system, vented into the air cleaner, except non-originality and potentially ugly tubing runs.

Right, the extra tubing usually doesn't look good. But if you can pull it off after the test, then it really isn't much of an issue at all.:LOL: Just plumb it up to pass and forget the looks.

In Sacto.
 

Gunner:
If you go to the BAR on Florin in Sacto, George is going to want to see incoming/outgoing in a closed loop; nothing escaping into the atmosphere. As soon as he sees you don't have it, he will show you a diagram and ask you to go home, follow it. If you show up with out the proper system in place, he'll turn you away and send you home on the spot, no pass go! It happened to Dan L. last week. He wants to see no breathers, tubes, vents or devices of any kind directly escaping into the atmosphere. Just trying to save you a 1/2 a day, trip over and back twice, if you can get it right the first trip there. I had a kit I gave to Dan, but he had to use part of it and still has part on his car. If you go to Florin, he will check, specifically. Just a heads up.

On the two times I passed the visual, I ran one from a breather on the valve cover to the air cleaner with a 90-degree fitting and the other from the back of the manifold to the back of the carb. The last time was for SB100 and I just had one line from the breather to the base of the air cleaner and it was approved.

Here is an original PCV diagram for 1965 390FE to reference/simulate from.

That's my understanding of how it's supposed to be, however many times another referee will let things slide. I'll do it right. If I do a clean job on the valve installation and plumbing, it will stay; I *might* pull off the vented breather for one that's open after the exam, just to reduce the tubing count.

After all (sigh) I have three months to do it. I could hand craft it out of popsicle sticks in that time. Or hand-carve it out of billet. Where'd I put my whittlin' knife...

a
 

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