Breather Gear Query
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Seasoned HDF Member
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From: Cental, MI
Breather Gear Query
The discussion on the Check ball has got me to thinking [dangerous]
First Thanks to Uncle Larry for the excellent pictures of the Breather and window, especially a well done cleaned-up window.
Second thanks to Johnjzjz for the 'It's Not Timed" comment...
Now, let's assume we have a reasonable, Checkball and spring...the Normal ones that sometimes allow a bit past but generally function.
The Oil pump has been investigated for sheared keys and it is in fact sending oil back to the oil tank in a reasonable fashion.
1) what would be the symptoms running a Shovelhead with no breather gear whatsoever?
My Assumption is Basically Nothing. Only indication will be that there will always/constantly be oil coming from the breather hose.
I think anyway.
2] What would be the symptoms of No Breather? I mean plugged ?
My assumption is ...Pressure...lots of it...The kind that pushes oil out of every orifice in the engine.
I think anyway.
3) What are the chances of getting a Steel [apparently quality but No Markings] breather gear that has the timing marks Not In Synch [in the wrong place] ??
Same pretty much as Either or Both 1-2, I think!!
4) What are the Chances that an engine with said "wrong" breather gear Ever worked Properly from day one???
Yea...Me Too.
All of this is guessing just now about a friends Bike... and I'm on the road for awhile..but I'm kinda Peeved, and kinda curious too.
I was blaming the God-Awful job of Breather port modification for some of his problems.
Back to Johnjzjz's Timing Comment...
This one Probably is Wrong!!!!
While my Shovel with the Badly tore-up breather cavity is a good candidate for an S&S reed...I'm starting to think a Reed breather is going to be a Great troubleshooting aid for my friends bike...Which I am pretty sure did Not Suddenly develop problems!!!
Course...I may be way off on some of my thinking...Hence, the questions I put forth.
Thanks All
First Thanks to Uncle Larry for the excellent pictures of the Breather and window, especially a well done cleaned-up window.
Second thanks to Johnjzjz for the 'It's Not Timed" comment...
Now, let's assume we have a reasonable, Checkball and spring...the Normal ones that sometimes allow a bit past but generally function.
The Oil pump has been investigated for sheared keys and it is in fact sending oil back to the oil tank in a reasonable fashion.
1) what would be the symptoms running a Shovelhead with no breather gear whatsoever?
My Assumption is Basically Nothing. Only indication will be that there will always/constantly be oil coming from the breather hose.
I think anyway.
2] What would be the symptoms of No Breather? I mean plugged ?
My assumption is ...Pressure...lots of it...The kind that pushes oil out of every orifice in the engine.
I think anyway.
3) What are the chances of getting a Steel [apparently quality but No Markings] breather gear that has the timing marks Not In Synch [in the wrong place] ??
Same pretty much as Either or Both 1-2, I think!!
4) What are the Chances that an engine with said "wrong" breather gear Ever worked Properly from day one???
Yea...Me Too.
All of this is guessing just now about a friends Bike... and I'm on the road for awhile..but I'm kinda Peeved, and kinda curious too.
I was blaming the God-Awful job of Breather port modification for some of his problems.
Back to Johnjzjz's Timing Comment...
This one Probably is Wrong!!!!
While my Shovel with the Badly tore-up breather cavity is a good candidate for an S&S reed...I'm starting to think a Reed breather is going to be a Great troubleshooting aid for my friends bike...Which I am pretty sure did Not Suddenly develop problems!!!
Course...I may be way off on some of my thinking...Hence, the questions I put forth.
Thanks All
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Posts: 12,878
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From: la la land jerzey
on the late evo motor with the head breather umbrellas the case was made that no breather valve was needed, and one of the guys took his out an swears he has had no issues < cant believe it why???
i know this is not exactly the same thing but they did it a different way and the point proves out, Indian chiefs 1933 to 1953 has a vane valve that created the oiling mist inside the block, the disc if a hole was put in it increased the amount of oil to the top determined by the size of the hole - the larger the hole the more oil to the point it would not stop smoking as no valve guide seals were ever used
so removing the breather increases the overall pressure in the block and this causes the gaskets to give way - every evo we take apart the breather hole is scored up was leaking -- every shovel we have taken apart the breather hole is scored the clutch primary cases and not returning oil correctly and leaking and most the rocker boxes are seeping
just something i have noticed is it in stone NO but the deal is always the same
i know this is not exactly the same thing but they did it a different way and the point proves out, Indian chiefs 1933 to 1953 has a vane valve that created the oiling mist inside the block, the disc if a hole was put in it increased the amount of oil to the top determined by the size of the hole - the larger the hole the more oil to the point it would not stop smoking as no valve guide seals were ever used
so removing the breather increases the overall pressure in the block and this causes the gaskets to give way - every evo we take apart the breather hole is scored up was leaking -- every shovel we have taken apart the breather hole is scored the clutch primary cases and not returning oil correctly and leaking and most the rocker boxes are seeping
just something i have noticed is it in stone NO but the deal is always the same
Thread Starter
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Seasoned HDF Member
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From: Cental, MI
^^ Interesting.
Way back when, on a post '77 sportster, we removed the Foo-Foo valve. Didn't help/didn't hurt it on the drag strip...when we built a Bigger Mill, we put a Bigger one way valve in it...felt it wasn't breating well enough so we ran a 5/8 hose from the timing Plug to the puke Bottle...Very little oil got in it...but lots of pressure came out!!!
Difference is...both Late EVO and Later IronHead were designed to breath much Taller in the system....shouldn't be much oil up there anyway.
I don't understand the statement that lack of a Oneway valve of some sort [or timed breathing] will cause excess pressure...Going by the Dragbikes I am accustomed to,they add an evacuation [vacuum] Pump...a Big one, and have no sighns of excess pressure in the Engine.
But, I'll try it someday to see what really happens to a Shovel run with No Breather gear at all..
Now...What about no breather at all...say a Blank [no window] breather gear is installed????
Way back when, on a post '77 sportster, we removed the Foo-Foo valve. Didn't help/didn't hurt it on the drag strip...when we built a Bigger Mill, we put a Bigger one way valve in it...felt it wasn't breating well enough so we ran a 5/8 hose from the timing Plug to the puke Bottle...Very little oil got in it...but lots of pressure came out!!!
Difference is...both Late EVO and Later IronHead were designed to breath much Taller in the system....shouldn't be much oil up there anyway.
I don't understand the statement that lack of a Oneway valve of some sort [or timed breathing] will cause excess pressure...Going by the Dragbikes I am accustomed to,they add an evacuation [vacuum] Pump...a Big one, and have no sighns of excess pressure in the Engine.
But, I'll try it someday to see what really happens to a Shovel run with No Breather gear at all..
Now...What about no breather at all...say a Blank [no window] breather gear is installed????
Cruiser
Joined: Jul 2011
Posts: 123
Likes: 1
From: Arkansas
Wait, wait, wait.......
The way it was explained to me is that there is a lot of pressure in H-D V twins because they actually breath. Car engines have a more constant pressure in the block because they are more balanced. In other words, one piston is going up and another is going down.
In a V-Twin that "gallops", the engine is sometimes full or pressure and sometimes it isn't. Therefore the engine breaths in and out. That's the reason for the "foo-foo" valve in the Sportster. My early EVO Sporty has a plastic valve built into the cam cover. You can't get them anymore either.
So there seems to be a reason for these "breather" devices or BT and Sportster riders would have ditched this stuff a long time ago.
The way it was explained to me is that there is a lot of pressure in H-D V twins because they actually breath. Car engines have a more constant pressure in the block because they are more balanced. In other words, one piston is going up and another is going down.
In a V-Twin that "gallops", the engine is sometimes full or pressure and sometimes it isn't. Therefore the engine breaths in and out. That's the reason for the "foo-foo" valve in the Sportster. My early EVO Sporty has a plastic valve built into the cam cover. You can't get them anymore either.
So there seems to be a reason for these "breather" devices or BT and Sportster riders would have ditched this stuff a long time ago.
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Seasoned HDF Member
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From: Cental, MI
^^ Yes...and the timed breather [on the older ones] helps scavenge also..
But, turns out it may have been overkill...huh? Since the Company got away from timed breathers early on..1977 on Sportsters and since it worked...about '92 or so on Big Twins.
Typically they breath out much more than in...hence the one way valving...Out Only..When racing..we tried alot of things..
The guys with evacuation Pumps [vacuum] are having the best luck..actually sucking the air out of the engine...I guess you would say..lots of Extra Out!!!
But, turns out it may have been overkill...huh? Since the Company got away from timed breathers early on..1977 on Sportsters and since it worked...about '92 or so on Big Twins.
Typically they breath out much more than in...hence the one way valving...Out Only..When racing..we tried alot of things..
The guys with evacuation Pumps [vacuum] are having the best luck..actually sucking the air out of the engine...I guess you would say..lots of Extra Out!!!
Seasoned HDF Member
Joined: Nov 2006
Posts: 12,878
Likes: 5,449
From: la la land jerzey
^^ Yes...and the timed breather [on the older ones] helps scavenge also..
But, turns out it may have been overkill...huh? Since the Company got away from timed breathers early on..1977 on Sportsters and since it worked...about '92 or so on Big Twins.
Typically they breath out much more than in...hence the one way valving...Out Only..When racing..we tried alot of things..
The guys with evacuation Pumps [vacuum] are having the best luck..actually sucking the air out of the engine...I guess you would say..lots of Extra Out!!!
But, turns out it may have been overkill...huh? Since the Company got away from timed breathers early on..1977 on Sportsters and since it worked...about '92 or so on Big Twins.
Typically they breath out much more than in...hence the one way valving...Out Only..When racing..we tried alot of things..
The guys with evacuation Pumps [vacuum] are having the best luck..actually sucking the air out of the engine...I guess you would say..lots of Extra Out!!!
The guys with evacuation Pumps [vacuum] are having the best luck
the vacuum in the engine is to keep the piston rings from chattering and robbing power
Thread Starter
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Seasoned HDF Member
Joined: Jul 2014
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From: Cental, MI
BTDT...May even have one of my own.
Pressure robs power...lots of it. May even be the cause of your "ring flutter".
I'm Not gonna believe that taking the one way valve from any post '77 sporty or ? '91 Big twin is going to increase CrankCase pressure...
But, I will try it [Hell I have tried it on my '77 and on my Modified Bike]...
I need a Measuring device.....
Now...Back to Timed breather system..
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Cruiser
Joined: Jul 2011
Posts: 123
Likes: 1
From: Arkansas
Removing pressure from the bottom end...any Harley out here [Bowling Green] this weekend is gonna make too much pressure in the bottom end..
BTDT...May even have one of my own.
Pressure robs power...lots of it. May even be the cause of your "ring flutter".
I'm Not gonna believe that taking the one way valve from any post '77 sporty or ? '91 Big twin is going to increase CrankCase pressure...
But, I will try it [Hell I have tried it on my '77 and on my Modified Bike]...
I need a Measuring device.....
Now...Back to Timed breather system..
BTDT...May even have one of my own.
Pressure robs power...lots of it. May even be the cause of your "ring flutter".
I'm Not gonna believe that taking the one way valve from any post '77 sporty or ? '91 Big twin is going to increase CrankCase pressure...
But, I will try it [Hell I have tried it on my '77 and on my Modified Bike]...
I need a Measuring device.....
Now...Back to Timed breather system..
To be honest, I never ever saw one of those "foo foo" valves on a Sportster. They always just had a straight dump tube off the front of the cam cover. Was thinking about doing that with my 87' Evo Sporty. It has a plug where the dump tube goes.
Speaking of which, if a Sportster can get away with no one way engine valving, why can't the Big Twins ? You guys have already explained that it helps with scavenging. If that's the case, why can't an oil pump with a bigger scavenge side handle that. I know they are already out there.
This seems to be a problem with the bigger stroker and race engines. I never saw a stock Sportster or 74" Shovel have these problems.
To test, you need a vacuum and pressure gauge. Provide a way to turn the motor over without it starting. After establishing a base line, you would test with the engine running. Not like i've done anything like that though. I'm still trying to figure why my engine was puking out oil just kicking it. I think the engine was wet sumping.
I think a lot of this today is EPA crap and they are just trying to keep oil off the ground.
Last edited by vanmor; Jun 23, 2016 at 09:26 PM.
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From: la la land jerzey
that us the reason the 40s indan makes more pressure when the disc is drilled as it lets even more air in to the engine then it would normally, because the air that is trapped does not let, extra === even more in to increase the pressure unless the barn door is left open < no breather or in the indain case a drilled hole for increased lube causes more pressure the gulp affect
Cruiser
Joined: Jul 2011
Posts: 123
Likes: 1
From: Arkansas
OK.......
That makes some sense. I'm thinking about the age old question of why these bikes puke oil sometimes. That's the output side. Where is the intake side ? What is causing the intake of air into the cases ?
Man, if you take out the timing plug with the engine running, there is a lot of air coming in and out that hole. I know it can't be just blow by. Does the rotating assembly cause that much turbulence in the cases ? And why is the breather valve in the cam chest area ?
That makes some sense. I'm thinking about the age old question of why these bikes puke oil sometimes. That's the output side. Where is the intake side ? What is causing the intake of air into the cases ?
Man, if you take out the timing plug with the engine running, there is a lot of air coming in and out that hole. I know it can't be just blow by. Does the rotating assembly cause that much turbulence in the cases ? And why is the breather valve in the cam chest area ?