FRESH AIR - aka PCV

[Wayne G.]

Anyone car to comment on the importance of a PCV, reason I ask is I always see the smoke from the breather/oil fill on my 60 Vette.

It has the draft vent tube also and that puffs a little...

Would it be wise to add a PCV setup, I am running a carb so not FI to worry about for now.. will it keep the motor in better shape? Oil is change fairly often, maybe to often 1k... or twice a year...

I was thinking just taking a breather/oil fill cap with the hose port attachment and adding a PCV inline and just putting that to the car? Or I have the air inlet port on the bottom of the air cleaner and just run that straing without a PCV ?

[Terry M.]

Re: FRESH AIR - aka PCV

Wayne,

The PCV is only part of the system. The carburetor has to be set up for the added air input from the PCV valve. I don't know enough about carburetors to advise you how feasible it is to modify a non-pcv carb to work with a PCV, but others may.

[Duke W.]

Re: FRESH AIR - aka PCV

The majority of blowby is unburned fuel-air mixture so the advantages are less crankcase dilution, better fuel economy, less air pollution, and less obnoxious odor when driving to name a few.

"Positive" means that inlet manifold vacuum is used to draw a continuous flow of fresh air into the crankcase, which rapidly purges blowby and directs it back into the inlet system.

There are no downsides if the PCV system is properly engineered.

You should be able to purchase the RPO 242 PCV system parts used on 1961 California engines and integrate them into your '60, so it will look OE.

Duke

[Ian G.]

Re: FRESH AIR - aka PCV

Duke, will this work for a 59 fuelie as well without any other adjustments necessary? if not, do you know what might need to be done? After judging, I'd like to do this conversion myself.

[Joe L.]

Re: FRESH AIR - aka PCV

The majority of blowby is unburned fuel-air mixture so the advantages are less crankcase dilution, better fuel economy, less air pollution, and less obnoxious odor when driving to name a few.

"Positive" means that inlet manifold vacuum is used to draw a continuous flow of fresh air into the crankcase, which rapidly purges blowby and directs it back into the inlet system.

There are no downsides if the PCV system is properly engineered.

You should be able to purchase the RPO 242 PCV system parts used on 1961 California engines and integrate them into your '60, so it will look OE.

Duke

Duke------

Except for this part [not for sale]. However, I think a functional replacement is available.

One other comment: Back in the day when California started requiring PCV on a retrofit basis on older cars as well as on new cars folks thought this was the worst thing that ever happened and would destroy engines. But, that was nonsense; it was actually a benefit.

[Duke W.]

Re: FRESH AIR - aka PCV

For sure adding the RPO 242 parts will require adjusting the idle speed and mixture. The part I'm not sure about is where on the FI manifold you can route the PCV outlet.

Of course you also need a "breather" type oil filler cap, which I expect you already have.

Duke

[Ian G.]

Re: FRESH AIR - aka PCV

I found two pics on the internet of this. One has two hoses and one has one hose. It looks like it connects into a fitting where the cranking signal valve would go on the doghouse. The other end would go into a fitting where the draft tube would normally go. On the one pic though I'm not sure where the smaller hose would go, or if its necessary given the other pic doesn't include it. Looks like the parts for RPO 242 are the PCV
CV590 PCV Valve 5649689 superceded by CV590C 6421934 (which appears to be a lot cheaper on eBay - go figure) and the adapter CV 214, with part 5646190 being the later service replacement. Here are some pics.

[Joe L.]

Re: FRESH AIR - aka PCV

I found two pics on the internet of this. One has two hoses and one has one hose. It looks like it connects into a fitting where the cranking signal valve would go on the doghouse. The other end would go into a fitting where the draft tube would normally go. On the one pic though I'm not sure where the smaller hose would go, or if its necessary given the other pic doesn't include it. Looks like the parts for RPO 242 are the PCV
CV590 PCV Valve 5649689 superceded by CV590C 6421934 (which appears to be a lot cheaper on eBay - go figure) and the adapter CV 214, with part 5646190 being the later service replacement. Here are some pics.

Ian-------


I expect the small hose is a vacuum take-off for some other function. Doing a "piggy-back" like this avoids the need to drill/tap another fitting into the manifold.

By the way, the AC CV590C is GM-discontinued although there are probably plenty still around at this point. However, I believe one could also use a GM #19250958, aka Delco 214-2295 which is currently available and inexpensive.

[Domenic T.]

Re: FRESH AIR - aka PCV

I might add to the good. When they started using the PCV valve it reduced the SLUDGE build up in the engine from trapped oil vapors. Then especially helped when they went from valve cover to valve cover breathing. That stopped the sludge build in the whole engine.

Dom

[Mike E.]

Re: FRESH AIR - aka PCV

The smaller hose would be for the washer system. (To the vacuum tank)

[Ian G.]

Re: FRESH AIR - aka PCV

Cool, thanks Joe. Mike Ernst thinks the small hose goes to the washer system. Since I have no washer on mine, I just need the one hose presumably. I just got a CV590C on eBay for 16 bucks shipped, so it can still be had relatively cheaply... Now to find the vent adapter for a song as well.

[Joe L.]

Re: FRESH AIR - aka PCV

Cool, thanks Joe. Mike Ernst thinks the small hose goes to the washer system. Since I have no washer on mine, I just need the one hose presumably. I just got a CV590C on eBay for 16 bucks shipped, so it can still be had relatively cheaply... Now to find the vent adapter for a song as well.

Ian------


The reason that the CV590 valves, aka GM #5649689, sell for so much more money is because they have been discontinued for so long and the supply of these has pretty well "dried-up". Some folks looking for "exact correctness" for an application originally using the CV590 are, presumably, willing to pay foolish prices. However, from a functional standpoint, the 590C will work just as well.