CJ-3B Bulletin Board

Pcv question. Ok, I promised, I've searched here and all over, and I'm still having trouble. I have an F 134 engine. There is a PCV tube coming out of the right side of the engine that is about 6 inches long and goes to nothing. When running, it sucks air in. I have a fuel pump with no vacuum ports. Where should this go? I've seen the pics but none tell exactly where this line should go. Help? I posted a pic of the side of the engine in a "what is this vent tube" thread a few days ago. Thanks you guys.

on your pic just posted
that tube comes around front of eng and ties into T that goes to valve cover
your tube that is cut is labeled as #14 on the following scan in SB it is shown as dotted lines as it is on RH side of eng

#14 cut tube


http://www.film.queensu.ca/CJ3B/Tech/ServiceBulletins1.html

Here is another pic. I think what is confusing me is that not only is there a ventilator on the top of the rocker cover, but there is a tube coming into the side of the intake right below the carb. The latter being the one that is sucking air. Fuel pump isn't the vacuum type, so I'm confused as to how this should be set up. I'm not trying for anything other than a solid operating engine. When the tube coming into the intake is plugged (as in the pic), it wants to stall. http://i39.tinypic.com/11tr96b.jpg[/IMG][/IMG]

Thanks for the link. I've seen so many fhead seatups and none are just like mine, that I called Walcks and talked to them. Basically, they told me to simply run a line with a PCV valve from the valve cover on the left to the intake port on the right and it would function as needed. He added that if I wanted vacuum wipers, then I'd have to do the whole re route through the fuel pump as indicated in the link. Thanks guys.

The pic you previously posted shows a SW or PU version of the Hurricane engine.
Both PU's and SW's with Hurricane engines used an open crankcase ventilation system.
The vacuum tube in question was not a part of any PCV system.
It is a remnant from the vacuum advance distributor as was used with all SW's and PU's.

This is normal and a slight increase of idle speed by adjusting the throttle valve linkage is all that should be required.

That advice is not correct.
The open ventilating system is not compatable with the various closed systems.

F-134 Hurricane engines used 4 differing types of crankcase ventilation systems.
1 was an open system and 3 were closed ventilation systems.
The open crankcase ventilation system used for the F-134 Hurricane engines consisted of a "Ventilator".
This is commonly called a "road tube" or "down draft tube".
This ventilator extends down from the rear of the side valve cover.
Unlike a closed system this open system has no connection to the intake manifold and uses no valve.

Willys Motors used the open crankcase ventilation system for only a few early years.
To my knowledge the open crank ventilation system was never used on Military nor on CJ models. Why not ?
My guess is that a closed system was considered a mandate for jeeps capable of deep water fording.
A down draft tube submerged in water will be an engine killer.
Later it was discovered that internal varnish accumulation was diminished by use of a closed system.
Apparently Willys Motors discovered this engine cleaning advantage somewhat by accident.
All modern vehicles now use a closed ventilation system.

Oldtime, thank you soooooo much. So basically, all I need to do is fabricate a side tube on the oild filter tube, and run a hose to the air cleaner and then just plug the spot where the old vacuum advanced distributor tube is sucking air? That would be easy. I saw the down draft tube coming out of the rear of the valve. I wont be doing any deep water fording, or any fording for that matter, so it shouldn't be a problem. I'll just adjust the idle on the throttle and go from there. Thanks so much.

I suppose you have a Donaldson air filter on your 3B ?
If yes it should have a tube extending from it to accept a hose.
Normally that connects to a nipple on the upper part of the oil filler tube.
I see that your oil filler tube is not vented.
Because the crankcase is ventilated at the valve cover breather cap it need not draw air in by way of the Donaldson air filter.
You can simply plug the filtered air output nipple on the Donaldson filter.
You should use a 1/8" pipe plug to plug the tap going into the intake mainfold just below the carburetor.
Note that this particular tap is the correct location to access when checking engine vacuum readings.

again, thank you. It is amazingly difficult trying to find out about which engine came from where, what it is supposed to be set up like, etc. Your knowledge is invaluable.

No biggy, I just find it all interesting.

I find that to fully comprehend the Jeep one must compare the differing standards used for the various Willys models.

I focus anywhere from the 1941 mass production MB/ GPW to the end of CJ's in 1985.
I focus more intently from 1950 (early Hurricane) through 1971 (end of Hurricane)
I focus most insently around the 1959 era where the universal time proven standards
have reached there peak duration concerning all of the various sub assemblies.
What I refer to as the central standard time proven universal production.

I think it is important to carefully evaluate available information. Taking supplied information at face value can often seem incomplete or worse yet, contradictory, if not carefully studied or supported by additional documentation.

Ken states:

and then gives detailed background info on the different ventilation systems.

While I find the background information invaluable (and I hope all this gets incorporated on the PCV page), and I agree with Ken’s assertion that this engine came from a different vehicle (I see your carb inlet orientation looks different from what I’m accustomed to), I don't agree with Ken's conclusion. Here's why. The link provided by ba25 (Service Bulletins) takes us to the page where the ventilation system conversion instructions (from Willys) is located. The fact that these instructions exist supports Ken's position on how ineffective the open ventilation system was – the manufacturer offered the conversion as an early option. Plus, page one clearly points out all F-head engines would eventually have the closed system as standard equipment.

In my opinion, a more correct conclusion of Walck's advice would have been, "That advice is incomplete." The fact is, based on the instructions, the advice would work. The only thing missing is the replacement of the breather cap on top of the valve cover ( per Step 1). Or retrofitting with the hoses that connect to the oil bath breather. Omitting either of these doesn’t render the PCV plumbing ineffective. Tooge I also notice you don't have a port on your filler neck for a hose either (or at least can’t see it). If so, adding a hose from the oil bath breather to your filler neck is not an option either. Or it would require additional modifications to add these fittings in order to add the hoses.

Here you can clearly see the two hoses that come from the oil bath breather that attach to the valve cover and the filler tube (this is the air inlet for the closed system most early F-Heads have):



Additional image: http://www.film.queensu.ca/CJ3B/Photos/Own...EngineRight.jpg

Later models omit the valve cover fitting altogether (note hose running directly to filler tube from oil bath breather):



Additional image: http://http://www.film.queensu.ca/CJ3B/Pho...0EngineLeft.jpg

Ken states:

Here I get lost as this initially seems contradictory. If the breather on the valve cover functions as a oil fill cap, the engine wouldn’t need an oil filler tube. If the oil filler tube exists, there would be no need to use the valve cover breather as an oil fill cap. In tooge’s posted picture we can clearly see the oil filler tube in place. I confess I don’t know of all the multiple engine configurations but I feel it is more helpful to us all to tie any historical info back to the posted information and tie any of the multiple configurations to the posted topic – instead of redirecting and adding confusion. It would certainly help me out!

Upon further study of the posted instructions, I see it supports Ken’s information. Kit number 927066, Step 1, states to replace the existing Filler Cap (not just breather cap) with a new crankcase breather and filler cap. So apparently this breather cap IS a filler cap. But, it also tells me the valve cover breather is NOT omitted (when converting to a closed ventilation system) but replaced with a different one (probably with a better filtering element). There is no description, in the instructions, of retrofitting with an elbow and attaching a hose to the oil bath breather. Again, I can conclude from this that the lower PCV plumbing (as suggested by Walck’s) will work with the breather cap still on the valve cover – the engine still receives air, as intended per the instructions, just not filtered from either the newer valve cover breather/filler cap or through the oil bath breather hoses via the filler tube and valve cover fittings.

With that having been said, if the fittings exist on the filler tube and/or the valve cover, I feel they should be connected as indicated by the images above. That gives the best filtration for air drawn into the crankcase.


So, after rambling on for way too long, my opinion is to hook up the PCV connections as Walck’s suggests (following the instructions to modify and correctly orient the exhaust valve cover and adding the needed parts) then connecting to the intake manifold. Your engine would then have a closed system, excluding the fuel pump booster for the non-existing vacuum wiper motor.

this is soooooo confusing. In my pic, you can see there what I'm calling a "breather cap" over the rocker arm cover that seems to match the description from the service manual. There is also a downdraft tube on the rear of the valve cover. My biggest concern was what to do with the "vent tube sucking air" coming into the intake below the carb. If indeed, the breather cap over the rocker arm cover is allowing intake, and the downdraft is allowing output, then I would think simply plugging that intake would make it an open system, unless I need to get a real "breather cap" and put it on the front of the valve cover instead of the one on the rocker arm cover on top (as seen in the pics). Or, I could do what walcks suggested and simply see if this will do fine with a closed system?

Rus, I assumed from the engine pic provided, plus tooge recently stated his engine in fact has a venilator. (road draft tube)
It will do no good to add a PVC valve in with the open vented system.
That is why I stated Walks information to be incorrect.
It is incorrect for tooges application because tooge has the open ventilated system which was never a 3B standard.
Carl Walck was likely thinking how plumb up the 3B not an early SW or PU engine.
If need be I'll pin this down by using only the standard accepted (W/O) terms for the components and can define all of the various ventilation systems used.

when you say "because the crankcase is ventilated at the valve cover breather cap", are you referring to the down draft tube coming from the rear of the valve cover?

Tooge,
Sorry for the confusion. First, the top valve cover is “intake valve cover.” This is the one with the round breather/filler cap on top. This draws air into the engine. The side valve cover under your exhaust manifold is your “exhaust valve cover” that would have the vent tube attached to the rear of it if it were an open ventilating system. This exhausts air from the engine. If the exhaust valve cover were swapped front to rear and the needed parts were attached to it, then your exhaust valve cover would match the images that show a PCV closed system and you’d have what Walck’s described.

The vent tube sucking air on the passenger side under the carb (this is your intake manifold) is where the PCV plumbing terminates (you can see this on the posted engine diagram). So when it is correctly sucking air, any positive crankcase pressure that builds up in the crankcase is vented through the exhaust valve cover and through the Positive Crankcase Ventilation (PCV) valve and is sucked into the intake manifold to be recycled through the cylinders. Make sense? There are multiple images throughout this website (including the ones in this post) that show these connections.

Ken, I didn’t suggest combining the PCV with the open system. I’m in complete agreement with you on that: It would be completely pointless, not to mention nearly impossible. I don’t believe Walck’s was trying to suggest this either. I believe Walck’s was trying to describe how to add a PCV to tooge’s engine since it didn’t have one. And their advice agrees with the instructions previously mentioned on converting from an open system to a closed system. This was the position I was trying to emphasize. A closed system could be added provided the instructions were followed and the necessary parts added to route the crankcase ventilation plumbing around to the passenger side and plug into the “sucking” hole.

As you pointed out, the closed system is all that exists now and has multiple advantages over the open system. Also, if the owner wants to maintain an open system then all this discussion is not much more than an academic waste of bandwidth on my part. But that’s how I read it. Tooge’s first post is, “Where does it go?” Then ba25 supplied the answer and documentation. Then tooge posted again with more info revealing his engine was different and added he still had some confusion. Your responses were not incorrect (especially if tooge wanted to maintain his open ventilating system) they just took a sharp turn from what I interpreted as his original question. Which is why I suggested, "Walck's answer is incomplete," since we have two ways to go: Convert or stay original.

So, I guess the question back to tooge is this.
A.) Do you want a closed PCV system that - plugs into that port that sucks air, or
B.) Do you want to maintain the open ventilating system you currently have and stop the port from sucking air?

If A.) then you should be able to construct one from the advice Walck’s gave you and the information provided in this post.
If B.), ignore everything I posted and ignore what Walck’s said and do what Ken suggested and plug the sucking port.


Again, sorry for the confusion and the long posts.

tHANKS KEN AND Rus. I am going to go ahead and flip the exhaust valve cover, plug what will then be the rear port, and add the required parts to the front port. Then route it around to the passenger side and connect to the intake manifold port with a pcv valve along the way. This should give me a true closed system. And yes, my question was really where does this go, but I should have added "now what do I do with it?". You guys have been a great help. Thank you.
Incidentally, there is not an oiil filter on it either, so I'm going to install an oil bath filter and create the tube to that as well.