HarleyTechTalk

Technical Forums => Twin Cam => Topic started by: dave brode on May 25, 2020, 05:00:06 PM

Title: Venting the oil pan to atmosphere under the oil fill hole. Twin cam "A"
Post by: dave brode on May 25, 2020, 05:00:06 PM
Hello All,

I've seen that a popular shop does this. A line is run from a fitting placed under the dipstick, and a line run up and away from there that's open to atmosphere. Afaik, this is done along with, or, without, also returning the head breather holes to the pan, though either the primary side of the trans case, or, through the trans case on the other side.

Fwiw, it seems to me that one could return the head breathers to the oil fill tube also, through a separate drilling, of course.

Please comment if you have done either.

Thanks.

Dave
Title: Re: Venting the oil pan to atmosphere under the oil fill hole. Twin cam "A"
Post by: turboprop on May 25, 2020, 05:13:10 PM
I run a similar setup on a TC124a. This engine vents the oil pan from the hole in the oil spout for the oem vent to engine line. The setup includes plugging the hole on the engine case and running a line from that oil spout up and to the rear of the bike. The oem head vents remain intact and are run up over the engine and then down to a catch can. Works very well. The head vents are only tasked with whatever blow by occurs, the oil pan vent handles whatever air the oil pump sends to the oil pan. Very clean, no mess, and the engine case breathes very well. There are no one-way valves other than what is inside the rocker boxes.
Title: Re: Venting the oil pan to atmosphere under the oil fill hole. Twin cam "A"
Post by: Hossamania on May 25, 2020, 05:15:13 PM
I would not return the head breathers to any part of the oil pan, transmission, or primary, much of that discharge is water. Either back through the throttle body to be burned off as designed (not my choice) or vented to atmosphere or a catch can.
Title: Re: Venting the oil pan to atmosphere under the oil fill hole. Twin cam "A"
Post by: No Cents on May 25, 2020, 05:39:41 PM
  On my bike (a 124" T/C bagger with an "A" motor) I vent the head breathers directly to a catch can...and I vent my oil pan thru the side of the oil filler neck with a hose ran to the rear of the bike with a filter attached at the end. Seems to work very well. You definitely wouldn't want to dump your head breathers into your oil pan...at least I wouldn't after seeing what comes out of my catch can. It's mostly water with very little oil in it.

[attach=0]

[attach=1]
Title: Re: Venting the oil pan to atmosphere under the oil fill hole. Twin cam "A"
Post by: dave brode on May 26, 2020, 06:31:24 AM
Thank you, Gents!
Title: Re: Venting the oil pan to atmosphere under the oil fill hole. Twin cam "A"
Post by: Deye76 on May 26, 2020, 06:45:36 AM
No Cents, do you get much, if any, oil mist from that line run from the dipstick spout?
Title: Re: Venting the oil pan to atmosphere under the oil fill hole. Twin cam "A"
Post by: No Cents on May 26, 2020, 06:53:47 AM
  I haven't noticed any moisture at the filter...but I do have a one way valve in the hose.
Title: Re: Venting the oil pan to atmosphere under the oil fill hole. Twin cam "A"
Post by: Deye76 on May 26, 2020, 07:09:14 AM
Can you share a link to that valve? Thanks.
Title: Re: Venting the oil pan to atmosphere under the oil fill hole. Twin cam "A"
Post by: No Cents on May 26, 2020, 11:49:50 AM
 I bought it off E-Bay. It has 1/4" ID hose barb ends. It costs me $5.35.
Title: Re: Venting the oil pan to atmosphere under the oil fill hole. Twin cam "A"
Post by: les on May 26, 2020, 12:20:13 PM
This is what I have on my 124".  T-Man did my heads, and I elected to purchase the breather option.  My breather bolts that go through my air filter backing plate are solid, totally blocked off.
Title: Re: Venting the oil pan to atmosphere under the oil fill hole. Twin cam "A"
Post by: Ohio HD on May 26, 2020, 12:24:03 PM
Les, are you running one way inline valves on the hoses?
Title: Re: Venting the oil pan to atmosphere under the oil fill hole. Twin cam "A"
Post by: turboprop on May 26, 2020, 12:34:59 PM
Quote from: les on May 26, 2020, 12:20:13 PM
This is what I have on my 124".  T-Man did my heads, and I elected to purchase the breather option.  My breather bolts that go through my air filter backing plate are solid, totally blocked off.

This is how my S&S 4-⅛" bore heads are set up. I have them plumbed into a vented catch can. No one way valves required as the one-way valves in the heads remain function-able. The air cleaner is attached to the heads with solid bolts vs banjo bolts.
Title: Re: Venting the oil pan to atmosphere under the oil fill hole. Twin cam "A"
Post by: les on May 26, 2020, 01:00:43 PM
Quote from: Ohio HD on May 26, 2020, 12:24:03 PM
Les, are you running one way inline valves on the hoses?

What turboprop said.  My "sewer" is down near just behind my tranny drain plug.  It's a filter.  I have a half dozen of those filters on my shelf.  Every once in a while, I'll take 30 seconds to put a brand new one on.  My throttle body intake is only dirty from the slight bit of dust that gets in that sticks because of the gasoline. 

Two rubber hoses on the fittings, to a "T" connector (serves as a "Y" connector), the single hose runs up the backbone, down past the coil, and down to the single "sewer". 
Title: Re: Venting the oil pan to atmosphere under the oil fill hole. Twin cam "A"
Post by: 98fxstc on May 26, 2020, 03:53:58 PM
Quote from: les on May 26, 2020, 01:00:43 PM
Quote from: Ohio HD on May 26, 2020, 12:24:03 PM
Les, are you running one way inline valves on the hoses?

What turboprop said.  My "sewer" is down near just behind my tranny drain plug.  It's a filter.  I have a half dozen of those filters on my shelf.  Every once in a while, I'll take 30 seconds to put a brand new one on.  My throttle body intake is only dirty from the slight bit of dust that gets in that sticks because of the gasoline. 

Two rubber hoses on the fittings, to a "T" connector (serves as a "Y" connector), the single hose runs up the backbone, down past the coil, and down to the single "sewer".

Doesn't make sense to me to run a gravity feed line uphill
the idea is to take the waste away, not have it sitting in the line where it could back up
Title: Re: Venting the oil pan to atmosphere under the oil fill hole. Twin cam "A"
Post by: No Cents on May 26, 2020, 05:11:16 PM
   :wink:   downward slope so the muck falls!  :up:
Title: Re: Venting the oil pan to atmosphere under the oil fill hole. Twin cam "A"
Post by: les on May 26, 2020, 09:36:21 PM
Quote from: No Cents on May 26, 2020, 05:11:16 PM
   :wink:   downward slope so the muck falls!  :up:

Oh, yeah!  That filter gets pretty yucky after a few thousand miles.  But not anything in the area of my air filter, throttle body, or cam chest cover.  I couldn't be more happy with this breather setup and I've tried a few.
Title: Re: Venting the oil pan to atmosphere under the oil fill hole. Twin cam "A"
Post by: turboprop on May 27, 2020, 05:02:48 AM
Quote from: les on May 26, 2020, 09:36:21 PM
Quote from: No Cents on May 26, 2020, 05:11:16 PM
   :wink:   downward slope so the muck falls!  :up:

Oh, yeah!  That filter gets pretty yucky after a few thousand miles.  But not anything in the area of my air filter, throttle body, or cam chest cover.  I couldn't be more happy with this breather setup and I've tried a few.

The one on my red bike seems to collect mostly water. After a couple hundred mies all that comes out is maybe a half inch of water in a cup and maybe a few drops oil.
Title: Re: Venting the oil pan to atmosphere under the oil fill hole. Twin cam "A"
Post by: 98fxstc on May 27, 2020, 05:41:41 AM
Quote from: turboprop on May 27, 2020, 05:02:48 AM
The one on my red bike seems to collect mostly water. After a couple hundred miles all that comes out is maybe a half inch of water in a cup and maybe a few drops oil.

and the line from your head breathers runs up the backbone ?
Title: Re: Venting the oil pan to atmosphere under the oil fill hole. Twin cam "A"
Post by: Deye76 on May 27, 2020, 07:49:22 AM
Quote from: No Cents on May 26, 2020, 11:49:50 AM
I bought it off E-Bay. It has 1/4" ID hose barb ends. It costs me $5.35.

Look like this?
https://www.ebay.com/itm/Aluminium-Check-Valve-6MM-1-4-One-Way-Non-Return-Inch-Air-Fuel-Oil-Diesel-Gas/174001941749?hash=item288352ecf5:g:lYMAAOSwYeZdWkkn
Title: Re: Venting the oil pan to atmosphere under the oil fill hole. Twin cam "A"
Post by: turboprop on May 27, 2020, 07:51:29 AM
Quote from: 98fxstc on May 27, 2020, 05:41:41 AM
Quote from: turboprop on May 27, 2020, 05:02:48 AM
The one on my red bike seems to collect mostly water. After a couple hundred miles all that comes out is maybe a half inch of water in a cup and maybe a few drops oil.

and the line from your head breathers runs up the backbone ?

Kinda sorta. I am not at home otherwise I would send pictures. The lines from the head vents on both of my TC124 FXRs are routed sort of over/next to the rocker boxes towards the front/left down tube and into a catch can. The oil tanks are isolated with their own vent line that runs up and towards the rear of the bike. No catch can involved. The port for the vent line on the engine case is plugged with an NPT fitting.

In this configuration, the head vents are only tasked with whatever pressure is internal to the engine. The oil tank vent is tasked with releasing the air pumped into the tank by the oil pump. No need to bring that air back into the engine only to be expelled through the head vents.

Paul Morris and myself have been running this system for over a year (couple years for me). It is very effective and extremely clean. I used to run the oil tank vent into a catch can but there was never anything in it. Maybe a few drops of water. The only reason I run the catch can on the heads is because I like to pay attention to what comes out. Sort of a way to monitor blow by and other stuff.

Title: Re: Venting the oil pan to atmosphere under the oil fill hole. Twin cam "A"
Post by: turboprop on May 27, 2020, 07:57:00 AM
Quote from: Deye76 on May 27, 2020, 07:49:22 AM
Quote from: No Cents on May 26, 2020, 11:49:50 AM
I bought it off E-Bay. It has 1/4" ID hose barb ends. It costs me $5.35.

Look like this?
https://www.ebay.com/itm/Aluminium-Check-Valve-6MM-1-4-One-Way-Non-Return-Inch-Air-Fuel-Oil-Diesel-Gas/174001941749?hash=item288352ecf5:g:lYMAAOSwYeZdWkkn

These work well for this application, are small, plastic and wont hack into finishes. S&S 50-8122.

(https://i.ebayimg.com/images/g/rlQAAOSwyuFepG5m/s-l1600.jpg)
Title: Re: Venting the oil pan to atmosphere under the oil fill hole. Twin cam "A"
Post by: Ohio HD on May 27, 2020, 08:05:14 AM
I have a few of these with 3/8" barbs John. If you need them, I'll send them to you, my treat.

Title: Re: Venting the oil pan to atmosphere under the oil fill hole. Twin cam "A"
Post by: Jim Bronson on May 27, 2020, 10:53:26 AM
I installed an A1 Cycles vent yesterday. After a ride there was no oil on the filter or hose, so I guess it's working OK. I did remove a little oil per the instructions before installing.
Title: Re: Venting the oil pan to atmosphere under the oil fill hole. Twin cam "A"
Post by: Deye76 on May 27, 2020, 12:52:17 PM
Quote from: Ohio HD on May 27, 2020, 08:05:14 AM
I have a few of these with 3/8" barbs John. If you need them, I'll send them to you, my treat.
Thank You Brian, much appreciated.
Title: Re: Venting the oil pan to atmosphere under the oil fill hole. Twin cam "A"
Post by: Ohio HD on May 27, 2020, 06:16:47 PM
Quote from: Deye76 on May 27, 2020, 12:52:17 PM
Quote from: Ohio HD on May 27, 2020, 08:05:14 AM
I have a few of these with 3/8" barbs John. If you need them, I'll send them to you, my treat.
Thank You Brian, much appreciated.

You're welcome. Goes out tomorrow.



[attach=0,msg1348898]
Title: Re: Venting the oil pan to atmosphere under the oil fill hole. Twin cam "A"
Post by: dynaglide on June 14, 2020, 10:31:43 AM
On a Dyna, I think you're talking about the red circle as the one to block off, right?
The fitting circled with green is the air from the tank, no?  So I could just run a hose with a filter from that fitting and not drill the tank by the oil spout? [attach=0]