PCV installation

[Jeff Balazs]

Hi Guy's;

My truck had a funky looking PCV arrangement on it when I got it.

The road tube had a rubber bung in it. Some one had punched a square hole in the front valve cover. There was a plastic hose fitting shoved into this hole and a PCV valve hung off this with hose back to the intake manifold. It may have functioned OK but I would like to come up with a cleaner looking and more reliable arrangement. The way mine was done servicing and checking for vacuum leaks would have been a bear.

Do any of you have photos of your PCV installations you can share?

Thanks, Jeff

[HanksB3B]

Jeff,

My truck had one of those also when I first got it. A few years ago there was a lot of back and forth on the boards about PCV systems. Some people are all for them and others like me don't believe in them.

Because I had no place to work on my truck back in the early days, I did most of the initial half century cleanup of my truck at a local car wash (this was 25 years ago) The guy that used to work there still does and still remembers the day he shouted "What are you fricken doing?" (toned down version) when he caught me removing handful after handful of sludge gobs behind the valve covers.

On a more personal note I'm a believer of getting rid of noxious gasses into the atmosphere and not pumping expelled petro chemicals back into my engine. I guess the only thing "green" about me is the color of my truck.

Hank

P.S. (here's the link P15-D24 is talking about below)

http://www40.addr.com/~merc583/mopar/framesets/softwareframeset.html

Edited April 15, 2012 by HanksB3B

[Guest P15-D24]

has the instructions for the factory set up.

[JBNeal]

here's greybeard's installation...it's a variation on the original Chrysler vacuumatic setup. There's other variations out there that modify a sealed-off replacement oil filler cap, but there has been some disagreement on whether a sealed cap is necessary to remove crankcase combustible gases or if it would cause some pressure build-up in the crankcase that may result in rear main seal leakage.

At any rate, my thinkin' is that those flathead valve covers that have been modified for a PCV system were done by someone who mimicked what was found on OHV engines, where PCV valves were placed in a rubber grommet atop the engine. It has been pointed out that the flathead valve cover would see more oil tossed at it than the oil filler tube or cap, so there may be more oil seepage at the valve cover than normal, and the PCV valve may get clogged up faster. Is the PCV system necessary to make the engine run better? no, but it helps...I think the 180F thermostat would make for a better running engine as sludge can be greatly reduced; the PCV system just makes it run cleaner.

[TodFitch]

...the PCV system just makes it run cleaner.

If by "it" you mean the crankcase oil, I agree. "Positive Crankcase Ventilation" does a better job of removing combustion byproducts from the crankcase and keeping the oil clean than a road draft tube.

The fact that "positive crankcase ventilation" (not "pollution control valve") also happens to clean up the major source of smog forming emissions from an otherwise "uncontrolled" engine is a happy side effect. The first PCV systems showed up on high end cars in the late 1920s. But since a road draft tube was much cheaper and deemed adequate Detroit did not install them on most vehicles. Exceptions being things like military vehicles where the other side effect of closing off low openings in the engine thus allowing fording of deeper rivers was sufficient reason.

If you dig back into the forum archives you'll find some simple ways of adding PCV systems to the Mopar L-6 engines. Here is one: http://www430.pair.com/p15d24/mopar_forum/showthread.php?t=13268#post110943

[Jeff Balazs]

Guy's

Thanks for your replies. Thanks to this forum I had already picked up on the 180 thermostat

For me it is not a question of omitting a PCV system.

I worked in a couple of garages that did fleet maintenance in the very early 70's. At that time many of the vehicles we serviced had PCV systems but some of the older ones did not. Being a young grunt I got all the line mechanics dirty work. The engines without PCV systems were always a mess.....even with regular oil changes. Once you have seen it from that prospective it is a absolute no-brainer. The only PCV related problems I ever recall seeing were worn out PCV valves and more often... vacuum leaks. Both of these can be dealt with easily.

I reckon I will do a variant of these ideas. To me the big thing with these sorts of installations is making it easy to service and check for leaks. If possible I don't want any of this system under or behind the manifolds. I think I will adapt the road tube and plumb it outboard of the manifolds similar to one of the examples shown. My intake manifold already has the provision for this.

I don't believe it is actually necessary to plumb the filler/breather up to the air cleaner however. I think that all that is really needed is a true breather cap with a provision for a filter. I am pretty certain this will work just fine and certainly make for a cleaner looking installation.

Hank......you are too funny. You know where all that sludge came from don't you?

Those expelled petrochemicals...... Well you paid for them......and guess what? They burn just fine. Take a look at the millions and millions of engines equipped this way. You are going to have to come up with a much better reason to not go green than this.

Thanks; Jeff

[JBNeal]

The function of the PCV system was also discussed here & here...

Edited April 21, 2012 by JBNeal

[Jeff Balazs]

49Dodge1ton;

Good point. I had not considered that in regards to the secondary system.

Will have to give the air cleaner mod some additional consideration. I was thinking of putting a K & N element in it already.

One question though.....since there was a form of this system installed how can you tell if the carb has stock idle orifice or the revised one already in place?

Thanks for your insight.

Jeff

[JBNeal]

Since I don't have the specifications on the stock idle orifice, I can't say for sure if it has been replaced, but I'd be willing to bet $$$ that it has not been replaced. I am assuming that the PCV replacement orifice is only a few thousandths different from the stock tube. The idle screw can be adjusted to offset the additional air introduced to even out the idle speed, rather than doing precise surgery on the carburetor.

Of note is one of the Chrysler air filter housing modifications that points the crankcase gases from the filler tube towards the carburetor throat. I have seen similar setups in other engines where PCV fumes are directed through the air cleaner and directly over the choke valve into the carburetor. If there was enough room on the carburetor, a fitting could be installed to direct PCV fumes directly into the carb. But since there isn't enough room or a flat boss on which to drill and tap an adequate port on the carb, the air cleaner housing has to be used to locate this port.