[Todd W. White]

Well, it WAS running poorly - after the stock PCV valve failed (it never did work properly), my highway mileage dropped to 12, at BEST. However, I didn't know what the cause was until I began to track it down. In fact, it never ran "right" since the rebuild a year ago - only "OK", and I chocked it up to being an old 283, and not a modern engine like I could have purchased from one of the sellers today.

After eliminating all kinds of possibilities, I was about ready to either park it or sell it. My in-town mileage was down to 8-9 MPG, and I couldn't afford to drive it. A couple of local mechanics graciously advised me where to look, and the search narrowed to the fuel delivery system.

That resulted in a new fuel pump, fuel filter, and a removal of the carburetor to let the guy that does carb's check it. When I pulled it, I found oil inside the intake manifold and the base of the carburetor. As I traced back through to find the source of the oil, I came to the conclusion that it was the PCV valve. I replaced it with 3 or 4 new ones, all of which "the book" said were "correct".

No luck. Same problem.

So, off came the carb again and, this time, I took it to the guy for a rebuild. I had a genuine factory kit for it, and he rebuilt it. When I went to pick it up, we discussed how it looked inside. He said that there were several channels and passageways inside that had oily crud (my word) stopping them up. This crud hindered my carb from operating properly, thus affecting efficiency, and, therefore, gas mileage.

Once clean, though, I didn't want to subject it to the same problem that gunked it up in the first place, so I began to look for an answer as to why it got there to begin with, and how to stop it from happening again. Of course, oil in the fuel also dilutes the octane rating of the gasoline, so that affected my mileage as well.

During my search prior to discovering the oil in the intake, I was replacing the plugs, and noticed that the passenger's side plugs were somewhat oily, but not the driver's side. My mechanic friends and I have concluded that the valve stem seals on that side are leaking oil, hence the oil being sucked out so readily, due to that being the same side as the PCV valve, which is installed in the valve cover on that side.

I installed the carb, but didn't run it yet. I decided to do more research before running it and dirtying it up again.

What I found was interesting:

1. As I have said, engines that have been modified from the original design won't work properly with the PCV valve originally specified. They may work "ok", but not like the engineers designed them to.

2. Engines that have aged, or have "issues" (valve stem seal leaking, stopped up or partially stopped up breather caps, etc.), will also not be properly served by the stock, OEM-specified PCV valve, because the entire crankcase ventilation system has been compromised.

3. A "catch can" is a viable, and reliable, way to reduce the amount of contaminants that get sucked through the PCV valve, back into the intake, and, thus, back into the engine.

4. However, most commercially available catch cans are all hype and don't do anything but look pretty as they sit there in your engine compartment - they do not do what you think they're doing. In fact, most do nothing at all.

5. There are a gazillion designs for catch cans out there, and most of them are flawed, at best. Most are downright useless. However, this article explains a properly designed catch can, and is sound, from an engineering standpoint:

www.conceptualpolymer.com/Air_Oil%20SeparationBeyondBasics.pdf

6. Since there are only 1 or 2 units available that are designed in a manner that follows the article listed above, and even they aren't in full compliance with it, I set out to build my own, as can be seen here:

http://www.persh.org/Pickup/PVCseparator.html

It wasn't hard, and it wasn't expensive.

And it WORKS.

7. I installed it, setup the carb, and began driving, carefully monitoring performance and mileage.

8. The results were ASTOUNDING! Even without a PCV valve, and with leaking valve stem seals on the passenger's side, my mileage in town went UP from around 8-9 to FOURTEEN, and my highway mileage wen from 12 to SIXTEEN!

I didn't believe it was possible, but, over and over again, I documented it carefully, and the results were virtually identical with each tank.

9. However - I was still fighting the vacuum from the intake as it sucked oil and contaminants from the port where the PCV valve used to be and my catch can was hooked up. I was emptying the can daily, and knew that there had to be more that could be done, in addition to replacing those seals (which I will be doing here shortly).

10. SO - more research. I found others out there, particularly the NOVA guys, who had similar experiences, or knew those who had.

The answer to my problem seemed to lie in making sure that my engine "breathed" properly. As I pursued this line of research, I talked to several professional mechanics that I trust, and, somewhere along the line, I came to the conclusion that I needed to put a PCV valve back in the circuit, so as to let the correct amount of fresh air into the engine while venting out the correct amount of gases.

My natural inclination was to look for one that was adjustable in the field, under actual operating conditions. To my amazement, no one had heard of such a thing, much less did they think it was necessary.

But I was convinced it was necessary, but could not find anyone who had one available. That is, until I discovered the Dual-Flow PCV Valve from ME Wagner. The guys at Steve's Nova site had found it, and were raving over it.

I went to the website. I read their engineering data and explanations, even the patent online. I called them and asked a bunch of questions. I discussed it with professional mechanics.

My conclusion was that I should save up and get one, especially since it carries a 30-DAY MONEY BACK GUARANTEE: if I didn't like it, all I was out was the time and trouble, plus postage back to the manufacturer.

11. So, I saved up, ordered it, and installed it. I called them, asked a few questions, and then watched the video they have - which is excellent - and calibrated it accordingly.

I then went back out on the road and began testing again.

The results were impressive.

My in-town mileage went UP from around 14 to a very consistent 16, and my highway mileage went UP from 16 to a very consistent 18, although I have achieved 19 on one occasion thusfar.

Incidentally - my engine performs amazingly better: I have power I didn't know I had, mileage I always wished I had, and it even SOUNDS better!

Now, I have said all of that to say this -

While I have never said installing the new-style PCV valve was a cure-all: what have and am saying is that removing the contaminants from the inlet to the base of my carb and, thus, into my engine, has increased my gas mileage, and the Dual-Flow PCV Valve has played no small part in that increase.

I hope this helps to "clear-i-fy" the issue, as they say in Texas.

- Todd