pcv on a 53 plymouth

[52concord]

so i just bought this 52 plymouth cambridge and i saw this hose connected to what looks like a pcv to the carb base, did this come from the factory? is that a pcv valve?

[JBNeal]

that is not a factory installation, but the adapter mounted on the block appears to be similar to the adapters used on Power Wagons.  At any rate, that's a start on a PCV system, as this will draw combustible fumes in the crankcase into the charge air stream.  That PCV valve looks similar to ones I have seen used on early slant 6s, as the PCV valve mounted in a rubber grommet in the valve cover with a hard line screwed into the valve from the intake manifold, similar to your installation.

[52concord]

alright thanks, so it will be safe to drive the way it is right now? and im guessing the pcv valve is the one screwed into the brass block on there?

Edited December 20, 2013 by 52concord

[TodFitch]

Is that, perhaps, a California car? I recall seeing some stuff indicating that California started requiring PCV on cars in the late 50s or early 60s. And sometimes things got retrofitted onto earlier cars.

[52concord]

might be not sure though, i do stay in california 

[blucarsdn]

Reviewing your pix I would say that your engine has been retrofitted with a PCV...

Having retrofitted several pre-PCV engines with a positive crankcase ventilator to eliminate the very ineffective "road draft tube" type of ventilation. The system you have should work very well. The only thing you should look at is the cap on the crankcase fill tube... The PCV has to draw air into the engine.crankcase, etc., therefore the cap must be an open vented type, in lieu of a sealed cap..

You should make sure that the PCV that was used is correct for the CID of the engine.. Under accelleration you need the vacuum to opererate the vacuum advance on the distribtor.

I have a Dodge flathead six out of a military power wagon  The engine has the sealed, "fording" kit, therefore it has a PCV in lieu of a road draft tube..The engine is mostlikely from the mid fifties.. Even the spark plugs are sealed to keep water out.. Bill

Edited December 21, 2013 by blucarsdn

[52concord]

alright so i pulled the pcv and the pcv im using is this one http://www.oreillyauto.com/site/c/search/PCV+Valve/02180/C0023.oap?year=1964&make=Chevrolet&model=Bel+Air&vi=1323414 should i get another one closer to my engine size or is that one okay? i looked under compatibility at the orielly website and it said the 1962 ford country squire with a 6 cyl 3.6l uses this pcv so i should be fine with it right?

Edited December 21, 2013 by 52concord

[Niel Hoback]

  That sounds like a good fit. I'd use it without worry.

[52concord]

alright and how should it be mounted? is it alright if its to the side or does it have to be vertical? with the thread part on the bottom?

[TodFitch]

alright so i pulled the pcv and the pcv im using is this one http://www.oreillyauto.com/site/c/search/PCV+Valve/02180/C0023.oap?year=1964&make=Chevrolet&model=Bel+Air&vi=1323414 should i get another one closer to my engine size or is that one okay? i looked under compatibility at the orielly website and it said the 1962 ford country squire with a 6 cyl 3.6l uses this pcv so i should be fine with it right?

If I did my calculation right, 3.6L is about 220 cu.in. Sounds close enough to me.

[Niel Hoback]

It doesn't matter how its oriented. Up down, or sideways.

[Grdpa's 50 Dodge]

IF you see a tap off the intake with a quarter turn valve on it,,,usually brass,,,in farm country.  It would look very similar to your pcv but with the quarter turn feature.  What would that be used for.  Let everyone guess for a little while and see if we have a winner winner, chicken dinner

[TodFitch]

IF you see a tap off the intake with a quarter turn valve on it,,,usually brass,,,in farm country.  It would look very similar to your pcv but with the quarter turn feature.  What would that be used for.  Let everyone guess for a little while and see if we have a winner winner, chicken dinner

Vacuum take off for the milking machine?

[Grdpa's 50 Dodge]

boy that didnt take long,,,you must be an old farm boy also!!!  LOTS of them around these parts on any motor that ran and started when cold.  When the electricity was out ,,,which was generally in a blizzard,,,and the cows had to be milked.  It was terrible slow as I recall but better than a one legged stool and a bent up pail.(specially when cows werent broke to hand milking)

[TodFitch]

boy that didnt take long,,,you must be an old farm boy also!!!  LOTS of them around these parts on any motor that ran and started when cold.  When the electricity was out ,,,which was generally in a blizzard,,,and the cows had to be milked.  It was terrible slow as I recall but better than a one legged stool and a bent up pail.(specially when cows werent broke to hand milking)

No, total suburbanite. But that topic has come up from time to time and I happened to remember it.

[blucarsdn]

To answer the mounting question... The PCV should be mounted so that the vacuum is pulling towards the spring, away from the valve within.. Depending on the style of the PCV the direction of installation can vary.. Many threaded type PCV's are intended to be threaded into the intake manifold, with the hose end away from the manifold.. The PCV's and valve there-in are designed to momentarilly snap closed upon accelleration.. If this does not happen, no vacuum for the vacuum advance..

In 1963 I got a new Chevy C10 pickup,, Within a year or so the engine would not accellerate, popping back through the carb.. I took the truck info a tune up, got it back and it still feel flat on it's face.. Took the truck to the Chevy dealer, got it back, still would not accellerate..

I use to purchase the factory repair manual when I bought a new vehicle... I got out the manual and read up on the tune-up spec's for the 6 cyln 230 engine.. The emmision section went into great detail about the function of the PCV... The importantance of keeping the "valve" clean was highlighted.. I removed the PCV, it was fouled with oil/sludge... Washing the vavle in solvent cleaned it right up.. 

I reinstalled the PCV and took the truck for a test drive.. Problem solved.. I drove down to the Chevy garage, I told the shop manager what I had found.. His response, the PCV's were something they normally did not service.. I pointed out the section in the factory manual covering "emmisions, PCV's".. The service maniger told me that he did not think they had such a manual in the their shop..

Another instance of.. "don't confuse me with facts, I already have my mind made up".. 

[52concord]

ohhhh alright this pcv is new to me since i always had plymouth with a draft tube, so say if i disconnect the tube from the carb a little blowby should be coming out of the hose at idle right, meaning the valve is open? 

[JBNeal]

if ya disconnect the tube from the carb, the carb now has a vacuum leak, causing the engine to run a tad lean.  Any moisture and combustible fumes in the crankcase would then stay there until they could escape through the vented oil filler cap and/or the PCV valve (if it was open).

 

additional information - PCV system operation 

Edited February 26, 2021 by JBNeal
revised information

[ptwothree]

I notice that most pcv conversations center around the pcv side and not much is said of the air intake side.  

 

Most pcv installs usually have the oil filler tube blocked off via a removable cap, with flex tubing installed from the air cleaner to the oil fill tube or valve cover.  This is done to filter the air being drawn into the crankcase via the pcv.  This would not be the case if air were introduced by way of the stock filler pipe/cap assembly.

 

That's the problem with the stock road draft tube set up.  And why engines would eat themselves up in a relatively short amount of time if operated in less than optimal conditions... something that existed to the max when these cars were new.

 

I wasn't a fan when they came out in the 60's but have come to realize that an engine equipt with a working and properly maintained pcv system will add quite a few miles to an engine before overhaul time......

[TodFitch]

I notice that most pcv conversations center around the pcv side and not much is said of the air intake side.  

 

Most pcv installs usually have the oil filler tube blocked off via a removable cap, with flex tubing installed from the air cleaner to the oil fill tube or valve cover.  This is done to filter the air being drawn into the crankcase via the pcv.  This would not be the case if air were introduced by way of the stock filler pipe/cap assembly.. . .

There is an air filter built into the oil filler cap: Thats what all that wire mesh inside the cap is about. It should be cleaned with gasoline or kerosene and then re-oiled with heavy motor oil at the appropriate service intervals. For my '33 the interval is listed as every 2000 miles.

 

The advantage, from the point of view of keeping unburned hydrocarbons from escaping into the atmosphere, of using the carburetor air filter for both the crankcase air filter and for the fuel mixture is that an older engine with more blow by than the PCV valve can handle is sucked into the engine via the carburetor rather than allowed to escape via the oil filler cap.

 

By the way, it is my understanding that PCV systems were first used on a few high end cars in the late 1920s. Not the 1960s. And the military used it back in at least the early 50s and maybe the 40s. But it cost more than a draft tube so it wasn't used on most cars until it was found to be the single biggest way to reduce smog producing unburned hydrocarbon emissions from cars.

 

So even though its main purpose is to extend engine life it got tagged as a anti-smog device and reviled as something bad. I knew a fellow back in the '90s who insisted on stripping off all that "smog junk" but failed to add a draft tube or other crankcase ventilation system. He had problems with seals and leakage due to crankcase pressurization. I attempted to explain to him what the system was and how it worked and that it was a good thing regardless of what it did for smog reduction but he could not get past the "must be only for smog control and it will hurt performance" so he did not replace it. Just kept replacing seals.

[blucarsdn]

I know several "performance minded" mechanics that have a closed mind to PCV's, classifying them as being "smog motors" and therefore a no no..

I agree with Todd's statement about blowing gaskets/seals, case in point; I know a man, Jay, that has a very nice '49 Chevy, with a SBC.. I have been on several car cruises with him, he always has trouble with oil blowing out of several areas of the engine.. Several of us guys have showed Jay the problem, no ventilation for crank-case pressure.. On two occasions, myself and another friend have installed a PCV system on Jay's engine during the course of a cruise... The return trip is always free of oil leaks..

The next time we see Jay, his car does not have a PCV because he has gone to his mechanic, thinking we are nuts and that he in fact has broken rings and/or a cracked piston.. His mechanic removes the PCV, telling Jay that we have ruined the motor, making it a 'Smog Engine".. We no longer bother, Jay's engine can just throw oil all over the place and he can call for the hook to take it home.. Bill

A foote note to my earlier comments:

Several years ago I read an aricle about engine emmisions.. The article stated that the common use of PCV's starting in 1963 reduced the engine emmisions by 95%.. All of the additional emmision controls have been installed to get rid of the remaining 5%..

Any clear thinking person should be aware of the fact that engines now last in excess of 200k, where-as engines in the "Good Old Days" were generaaly done at 50k..

Edited December 25, 2013 by blucarsdn