Vent line Function?

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laipappy
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Vent line Function?

#1

Post by laipappy » Mon Apr 25, 2011 2:45 am

What is the function of the vent line? I ask because I am thinking of T-ing the crankcase vent (oil dripper) to the engine vent line in order to circulate the expelled oil back into the oil tank instead of onto the street. Will it harm the engine if oil goes back into the engine via the vent?



Panshovevo
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Re: Vent line Function?

#2

Post by Panshovevo » Tue Apr 26, 2011 1:20 am

I think you might blow a line, or bulge your oil tank if you don't have something vented to atmosphere to relieve pressure. At best, your oil consumption would probably go way up.
I can't really answer your question, as I don't yet understand why there are two separate vent lines, but I can add to it.
I've been considering putting a four way fitting in the vent line from the cam chest, running the crankcase vent into the bottom, and running another hose out the top, which would rise higher than the oil tank, then go back down to exit in it's normal position under the bike.
My theory is that oil from the sump(on startup) would get pushed into the oil tank rather than blowing out on the ground. Any thoughts? Any reason why these lines can't be connected this way?
Regards,
John

laipappy
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Re: Vent line Function?

#3

Post by laipappy » Tue Apr 26, 2011 6:46 am

Yes, what you said is the concept I am trying to achieve. Basically recirculate the sump oil at start up back into the tank instead of the street. Your idea simply adds another line to vent into the atmosphere. Have you tried this on your bike yet?

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Re: Vent line Function?

#4

Post by Panshovevo » Tue Apr 26, 2011 2:45 pm

laipappy wrote:Yes, what you said is the concept I am trying to achieve. Basically recirculate the sump oil at start up back into the tank instead of the street. Your idea simply adds another line to vent into the atmosphere. Have you tried this on your bike yet?
No, not yet. I ran it by one of the tech support guys at S&S, who thought it might work, but have been waiting to get more opinions before trying it.
I have also considered making a smaller version of the oil separator used on my aerobatic airplane, which captures oil blown out the breather during the transition from upright to inverted flight and back and returns it to the sump, while still allowing the engine to breathe freely.

Cotten
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Re: Vent line Function?

#5

Post by Cotten » Tue Apr 26, 2011 3:34 pm

laipappy wrote:Yes, what you said is the concept I am trying to achieve. Basically recirculate the sump oil at start up back into the tank instead of the street.
laipappy!

Why not just remedy the sumping problem?

....Cotten

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Re: Vent line Function?

#6

Post by Panshovevo » Tue Apr 26, 2011 4:06 pm

Cotten wrote:
laipappy wrote:Yes, what you said is the concept I am trying to achieve. Basically recirculate the sump oil at start up back into the tank instead of the street.
laipappy!

Why not just remedy the sumping problem?

....Cotten
Maybe, like me, he only has a problem if the bike sits for an extended period, about which as I understand, there is not a lot that can be done. The S&S tech I discussed the situation with, worked for a Harley dealership in the '70's and said that many new Shovelheads would blow significant oil out the breather after sitting on the showroom floor for a couple of weeks.

Anyone have a more helpful answer?

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Re: Vent line Function?

#7

Post by Underdoggie » Tue Apr 26, 2011 4:27 pm

Anyone have a more helpful answer?
I think what Cotten means is there is a tool that will burnish the valve seat in the oil pump and stop the sumping problem.

Cotten
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Re: Vent line Function?

#8

Post by Cotten » Tue Apr 26, 2011 6:02 pm

Underdoggie wrote: Anyone have a more helpful answer?
I think what Cotten means is there is a tool that will burnish the valve seat in the oil pump and stop the sumping problem.
Or at least slow it down... .. . . . .

Please use the search function for "burnisher".
Some are damaged beyond burnishing alone, usually by lapping, or beating with a drift.

....Cotten
PS: 1970s Shovelheads had the worst quality control ever.

laipappy
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Re: Vent line Function?

#9

Post by laipappy » Tue Apr 26, 2011 7:04 pm

Cotten wrote:
Underdoggie wrote: Anyone have a more helpful answer?
I think what Cotten means is there is a tool that will burnish the valve seat in the oil pump and stop the sumping problem.
Or at least slow it down... .. . . . .

Please use the search function for "burnisher".
Some are damaged beyond burnishing alone, usually by lapping, or beating with a drift.

....Cotten
PS: 1970s Shovelheads had the worst quality control ever.
Hi Cotten
I am familiar with your burnishing tool and concept and I have actually made my own version of one using common parts from the local hardware store. Where I am stuck at is getting a check ball and having someone weld the ball to the end of the screw end. In the meantime, my cul de sac has multiple oil trails that lead from my house to the main road, so I really need a fast fix!

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Re: Vent line Function?

#10

Post by Panshovevo » Tue Apr 26, 2011 8:00 pm

laipappy,
I slowed mine down considerably by pulling the spring and ball, cleaning and inspecting the ball to make sure it didn't have a groove worn in it, or other damage, then slightly stretching the spring and replacing the assembly.
Prior to doing this, it would blow oil if it sat overnight. Now, it only blows noticeable oil if it sits for close to two weeks.

laipappy
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Re: Vent line Function?

#11

Post by laipappy » Tue Apr 26, 2011 10:25 pm

Panshovevo wrote:laipappy,
I slowed mine down considerably by pulling the spring and ball, cleaning and inspecting the ball to make sure it didn't have a groove worn in it, or other damage, then slightly stretching the spring and replacing the assembly.
Prior to doing this, it would blow oil if it sat overnight. Now, it only blows noticeable oil if it sits for close to two weeks.
Thanks Panshovevo, your comments are appreciated!

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Re: Vent line Function?

#12

Post by ozwick86 » Wed Apr 27, 2011 5:37 am

I purchased a burnisher tool from Cotten back last October. I burnished the check ball on the pump and so far it appears to have worked based on the oil pan under the bike has minimal drippings. I plan to start the bike up and take her out for a spin this weekend, now that I can get my bike down the side of my house after removing all my kitchen remodel garbage. I will keep you posted.

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Re: Vent line Function?

#13

Post by Cotten » Wed Apr 27, 2011 1:19 pm

laipappy!

The ball should be low-temp silver-soldered to preserve its hardness, and then scrupulously polished to make the seat as smooth as possible.

And John!
I advise against stretching the spring.
A new spring and ball is not expensive.

...Cotten

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Re: Vent line Function?

#14

Post by Panshovevo » Wed Apr 27, 2011 4:16 pm

I did say slightly. I realize what could happen if there was too much pressure on the spring. It's a very weak spring, though.

Does anyone here understand the vent system well enough to answer the questions posed above?

Cotten
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Re: Vent line Function?

#15

Post by Cotten » Wed Apr 27, 2011 5:12 pm

Folks,

The breather system is not complicated.

One breather equilibrates the oiltank headspace with the cam chest.
The other is timed to open to atmosphere.
(When a motor gets warm, the insides expand, and must be relieved.)

Connecting the two makes it complicated.

Beware that any low loops of hose will collect oil mist, and then you really have a mess. That's why breather filters are a joke.

....Cotten

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