PCV Valves - UK/Europe - another plug
- Thread starter JTBS
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ashman said:
Ditto. I'm in Sydney. Here's my setup. The engine breathes independently of the oil tank.
The bike is a 1970 model with the distributor blanking plate. (I made a replica plate for this purpose so as not to spoil the original.) The home made catch tank just rests on the cradle with rubber pads.
Cheers
Martin
nortonspeed
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MFB said:Ditto. I'm in Sydney. Here's my setup. The engine breathes independently of the oil tank.
The bike is a 1970 model with the distributor blanking plate. (I made a replica plate for this purpose so as not to spoil the original.) The home made catch tank just rests on the cradle with rubber pads.
Cheers
Martin
Why bother making an extra catch tank if you already got one :wink: What is the advantage of the engine breathing independently of the oil tank :?:
You better connect that catch tank on the oil tank breather.
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nortonspeed said:
The advantages are:
1. Any blow-by from the engine is no longer fed into the oil tank.
2.The oil tank is not subjected to any air pressure, thus reducing its own breathing requirements.
To answer JimC's question, the purpose of the breather is to reduce crankcase pressure by evacuating air, not oil. The 1972 engines DO breathe quite a bit of oil due to the location of the breather near the bottom of the crankcase, but just because it was done that way doesn't make it right. Evidently the factory recognised this fact and used this arrangement only briefly. They seemed to struggle with the breathing question and never really got it right, hence the reputation for oil leaks.
Being an earlier model, my bike had the timed camshaft breather. I blanked it off, and drilled the timing side crankcase as per the later models.
Cheers
Martin
nortonspeed
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MFB said:
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Combat breather is not a bad feature [observe it function on cold starts] but the forward oil sump pick up sure is. Without that low down breather, big hose path, secondary back up Combat oil return, hi rpm Combat wet sumping would about hydro lock engine besides the mess. Plug front and open TS case to oil passage solves this quirk. Your call on skinning the one-way valve cat.
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For christs sakes, man give it up. A pressurised crankcase is bound to be more likely to pass oil than one with a vacuum. You really do astound me with your contravention against laws of physics. You, a man supposedly educated in the discipline of medicine.
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Please point out what is so upseting to you. A 1-way valve helps duh, so pick what pleases ya, I'm so long sold on low crankcase pressure I'm going rather further on Peel with common slang "active extractor" but technically termed an "eductor". *Please point out another example of that feature in a Norton.*
My only point you seem confused on is that I think, nay know, the Combat breather turns out to be a saving grace > with the sump drain up front. Restated, it does not lower pressure, only excess oil level when running Hard. I am open to pointing out any public error in the subjects you list, so have at it to refine my foolishness or clarify your own.
My only point you seem confused on is that I think, nay know, the Combat breather turns out to be a saving grace > with the sump drain up front. Restated, it does not lower pressure, only excess oil level when running Hard. I am open to pointing out any public error in the subjects you list, so have at it to refine my foolishness or clarify your own.
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Air PRESSURE in the oil tank is not a problem, it's the contaminants from engine blow-by that I want to eliminate from the oil.
However, in a way, the stream of air from the engine DOES cause a problem, especially for bikes with the central oil tank:
It exacerbates the tendency for the oil tank breather to dribble oil into the air filter, making a mess. DogT solved this by running a hose through the air filter end plate and into a catch bottle.
By disconnecting the engine breather from the oil tank, I was able to utilise that port as an oil tank breather port to atmosphere. Then I was able to plug the original breather which went into the air filter.
Actually this was a big factor in my decision to go to all that trouble. I neglected to point that out previously. Sorry for any confusion.
In general terms, it seems somewhat bizarre to me that engine blow-by gases would be piped to the oil tank at all, except that it is a cheap and convenient way of disposing of them.
"Accountancy engineering" played a big part in the British motorcycle industry.
I'm no engine expert, but don't wet-sumped engines have crankcase ventilation systems in part for the purpose of removing crankcase fumes from the oil reservoir?
Cheers
Martin
However, in a way, the stream of air from the engine DOES cause a problem, especially for bikes with the central oil tank:
It exacerbates the tendency for the oil tank breather to dribble oil into the air filter, making a mess. DogT solved this by running a hose through the air filter end plate and into a catch bottle.
By disconnecting the engine breather from the oil tank, I was able to utilise that port as an oil tank breather port to atmosphere. Then I was able to plug the original breather which went into the air filter.
Actually this was a big factor in my decision to go to all that trouble. I neglected to point that out previously. Sorry for any confusion.
In general terms, it seems somewhat bizarre to me that engine blow-by gases would be piped to the oil tank at all, except that it is a cheap and convenient way of disposing of them.
"Accountancy engineering" played a big part in the British motorcycle industry.
I'm no engine expert, but don't wet-sumped engines have crankcase ventilation systems in part for the purpose of removing crankcase fumes from the oil reservoir?
Cheers
Martin
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Yes, they do have crankcase ventilation systems. I don't know that its main purpose is to remove crankcase fumes from the reservoir. None, that I know of, use a separate catch can or bottle. The breather is plumbed back to the engine, usually to a valve cover.
I question whether blow-by contaminates are separate from the sump oil and are a problem. Possibly so. My take on it, if blow by contaminates were separate and a problem, engine manufactures would not combine blow-by with engine oil by venting the crankcase back to the engine. Years ago crankcases were vented to the atmosphere with what was called a road draft tube. The road draft tube has long been gone. As for oil contamination, my 2004 Honda CRV had a recommend oil change schedule of 10,000 miles. My 2013 Honda CRV has a maintenance minder. First and only, so far, oil change was at +8,000 miles.
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MFB said:
Upon further reflection, you are correct. For some reason I was thinking backwards this morning. My apologies to you and the forum. Although I would add, in the case of our Nortons, the crankcase ventilation is probably more for relieving crankcase pressure than ventilating blow-by contaminates. Your explanation would explain the benefits of separating the crankcase ventilation from the oil tank. I stand corrected.
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Oil contamination Chemistry wise it don't matter if blow by gases vented to outside or into oil tank or sucked into manifold as the reactive blow by elements, moisture and free radicals and hydrocarbon mineral acids are reacting inside the crank case where most the heat and agitation-aeration are happening, so what is expelled-vented has already done its oil damage.
The problem with British Iron is the air cooled parts don't seal as well as water cooled so tends to blow by enough its polluting to point of coking up the jugs besides helping oil air filter. Modern automotive engines don't have venting to oil tank because they have wet sump pans and its the same pressure and source being vented, ugh.
Going by Comstock's measures each lb below ambient frees up almost a hp in our size engines which is remarkable cheap hp adder but takes dangerous illegal activity to fully appreciate.
The best way is Peel's [my] way of course :wink: - to activity pump vapors out of crank case into exhaust exit with enough suction to pull in fresh air through a tiny air filter in rocker cover down into crank case and still remain well below ambient yet not pull engine oil out with it. Flushes out moisture and reactive vapors so much less remains to react with oil and metal surfaces microscopically corrosively chipping-pitting away at the finishes and clearances. If 'she' can reach say 5-6 PSI below outside would that be felt in her response and improve oil change intervals?
The problem with British Iron is the air cooled parts don't seal as well as water cooled so tends to blow by enough its polluting to point of coking up the jugs besides helping oil air filter. Modern automotive engines don't have venting to oil tank because they have wet sump pans and its the same pressure and source being vented, ugh.
Going by Comstock's measures each lb below ambient frees up almost a hp in our size engines which is remarkable cheap hp adder but takes dangerous illegal activity to fully appreciate.
The best way is Peel's [my] way of course :wink: - to activity pump vapors out of crank case into exhaust exit with enough suction to pull in fresh air through a tiny air filter in rocker cover down into crank case and still remain well below ambient yet not pull engine oil out with it. Flushes out moisture and reactive vapors so much less remains to react with oil and metal surfaces microscopically corrosively chipping-pitting away at the finishes and clearances. If 'she' can reach say 5-6 PSI below outside would that be felt in her response and improve oil change intervals?
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JimC said:
No worries Jim. And you're right, the Norton breather is as much for relieving crankcase pressure as it is for ventilating blow-by. But it DOES vent this blow-by, and to deliberately pipe it into the oil tank just seems wrong.
As far as pressure relieving is concerned, Jim Comstock's crankcase-mounted breather valves appear to be the gold standard, but they do carry quite a bit of oil due to their location, so they need to be routed to the oil tank.
And as I said, I very much wanted to eliminate the oily air filter situation. Separating the oil tank from the engine breather sort of killed two birds with one stone.
Cheers
Martin
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hobot said:The best way is Peel's [my] way of course :wink: - to activity pump vapors out of crank case into exhaust exit with enough suction to pull in fresh air through a tiny air filter in rocker cover down into crank case and still remain well below ambient yet not pull engine oil out with it. Flushes out moisture and reactive vapors so much less remains to react with oil and metal surfaces microscopically corrosively chipping-pitting away at the finishes and clearances. If 'she' can reach say 5-6 PSI below outside would that be felt in her response and improve oil change intervals?
I like it. I like it a lot. :mrgreen:
ashman
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I have been running a catch bottle on my 850 Fearterbed for 33 years now, when I first built it I had the breather going back to the wideline oil tank but it had so much pressure in the tank it was blowing oil out of the cap, the tank also had a breather, but as soon as I run the breather to the catch bottle it stopped that leak, I have a 2 litre round bottle inbetween my engine mounts, I have the engine breather hose go in the top of the bottle as well as my oil tank breather, the hose fit nice and snug with enought gap for air, the breater hoses sit half way into the catch bottle, this has worked for me and only get less than 100ml of oil in the bottle after about 12 months, so not much oil at all, now I am going to install Mikes PCV valve to stop it blowing back into the crank case, my motor has always been oil tight since I have owned it for 37 years, but I do get a few little seepages from the head so thinking of also putting a small breather in the rear tappet cover and see if that helps.
Ashley
Ashley
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Thanx I think. Peel is as weird as I can be and I got this way runing straight into trees or twisting off fasteners and blowing up stuff so pensive what to expect. The images is not the proper way to do an exhaust header "eductor" but shows the principle. If not done right then at low rpm slow pulses it can pump pressure back into cases so still good id to fit a flapper in between. Peel pipes will Y together so will place tube beyond that to get both pulses past it. Theres a O2 sensor bung a few inches past the Y which distrubs flow too. Not sure where down stream of that to tap in, so will drill holes on old headers till finding the sweet spot, I hope. The other oneinarow weirdness is if I don't vent in through head the exhaust is only way for blow by to get out and these venturi things can really suck once flow past going good. There is a one way in air valve on frame tank to prevent oil spills when crashed sideways. Sump pump is twice oil input so may over pressurize the OIF volume and back up into crank cases. Try to fall asleep thinking of all the balanced and unbalanced flows and pressures and drains and returns in all positions to gravity and accelerations and what could possibly go wrong. Then throw in oil jets oil volumes of another gallon/min in and out, if I can even install them, as stymied so far. In Peel's case this all for a few extra hp and ability to sustain that heat and flows, not just leaks. What would be ideal is to need a metering valve on the sucker to throttle back below oil seal inversion.
On 10/20/2010 9:19 PM,
>
> Eductors are pumps without moving parts, driven by pressurized fluid flow.
>
> from a Bob Patton 1996 forum discussion.
>
> So, when you cut into your exhaust system to tie in your eductor port, try to do so in a straight run, favoring a location closer to a downstream bend and farther away from an upstream bend. Avoid locations where the cross section increases, these locations trade velocity for pressure and are inimical to eductors. If you have to locate your port in a bend, locate it in the throat and avoid the heel. Avoid locating the tube so that it protrudes into the exaust flow. And finally, cut the tube that you are using for your port tie-in square, and locate it perpendicular to the long axis of your exhaust pipe and at the side or top of the pipe, not the bottom.
>
http://www.teglerizer.com/triumphstuff/ ... enging.htm
>
> For an eductor with gas as the power fluid:
> – Exhaust pressure should be less than ½ power-gas pressure (in
> absolute terms)
> – Exhaust pressure should be less than twice suction pressure
> – Mass flow rate of power gas will be about twice suction mass flow
> rate.>
>
> http://en.wikipedia.org/wiki/Eductor-jet_pump
> An eductor-jet pump or jet pump is a type of pump where the energy from one ... into the exhaust hose along with the fluid from the eductor jet nozzles
>
> http://www.foxvalve.com/iindex2.aspx
> Solids Conveying Eductors · ejector, ejectors, eductor, eductors. Air ejectors use compressed air or other gasses to create vacuum that can exhaust, vent
>
> http://cdfdata.fire.ca.gov/pub/fireplan ... epdf29.pdf
> 5. EXHAUST SYSTEMS 5.1 Normally Aspirated Diesel Engines
> File Format: PDF/Adobe Acrobat - Quick View
> maintenance cycle, and in some cases a 13 to 15-day cycle. Photograph 5-13. Dirty Eductor Tube. Photograph 5-14. Looking Down Exhaust Stack with Eductor
>
On 10/20/2010 9:19 PM,
>
> Eductors are pumps without moving parts, driven by pressurized fluid flow.
>
> from a Bob Patton 1996 forum discussion.
>
> So, when you cut into your exhaust system to tie in your eductor port, try to do so in a straight run, favoring a location closer to a downstream bend and farther away from an upstream bend. Avoid locations where the cross section increases, these locations trade velocity for pressure and are inimical to eductors. If you have to locate your port in a bend, locate it in the throat and avoid the heel. Avoid locating the tube so that it protrudes into the exaust flow. And finally, cut the tube that you are using for your port tie-in square, and locate it perpendicular to the long axis of your exhaust pipe and at the side or top of the pipe, not the bottom.
>
http://www.teglerizer.com/triumphstuff/ ... enging.htm
>
> For an eductor with gas as the power fluid:
> – Exhaust pressure should be less than ½ power-gas pressure (in
> absolute terms)
> – Exhaust pressure should be less than twice suction pressure
> – Mass flow rate of power gas will be about twice suction mass flow
> rate.>
>
> http://en.wikipedia.org/wiki/Eductor-jet_pump
> An eductor-jet pump or jet pump is a type of pump where the energy from one ... into the exhaust hose along with the fluid from the eductor jet nozzles
>
> http://www.foxvalve.com/iindex2.aspx
> Solids Conveying Eductors · ejector, ejectors, eductor, eductors. Air ejectors use compressed air or other gasses to create vacuum that can exhaust, vent
>
> http://cdfdata.fire.ca.gov/pub/fireplan ... epdf29.pdf
> 5. EXHAUST SYSTEMS 5.1 Normally Aspirated Diesel Engines
> File Format: PDF/Adobe Acrobat - Quick View
> maintenance cycle, and in some cases a 13 to 15-day cycle. Photograph 5-13. Dirty Eductor Tube. Photograph 5-14. Looking Down Exhaust Stack with Eductor
>
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ashman said:
During my initial phase of Commando ownership, I had a lot of trouble with a leaking head. I fitted a direct to atmosphere breather from the intake tappet cover running into a catch can as part of a fix. Turned out it was a bad RH4 head, which was replaced, but the breather stayed. it always pumped out a lot of emulsified oil on start up--thinking about this, it was pretty simple to realise that having a direct to atmosphere breather is going to always give you this--a certain amount of oil will sit in the hose, when the engine cools, moisture in the atmosphere will give you emulsion. In fact, it probably extends all the way into the rocker gear. This cannot be good. I fitted a small one-way valve (actually a PCV valve, I think) in the line close to the catch can as I could.So now, all I get in that catch can is a little water with a very thin film of oil on top. The same with my Buell X1-only a little slightly oily water, instead of what is commonly referred to as "splooge" People saying, "man, I'm glad I fitted that direct breather, don't want that splooge in my baby's motor" ---fool, you are the one putting it into the top of the motor in the first place, with a direct to atmosphere breather. And no, that cute little K&N on top of the catch can will not stop that, as some seem to think it will. Testing the breather line into a container of water is interesting. On start up, nothing initially, then, as pressure builds a little , the valve opens,a steady stream of bubbles starts, amount proportional to rpm. When you shut down, very large burst of air as the motor rocks to a stop.
Further down the track I fitted an XS650 valve in the breather line to tank, but have ridden it very little since . There is a very slight weep which develops cross the fins on one side at the head joint after prolonged highway running--I'm not going to change the head gasket yet, I'd like to see if it goes with this mod.
I have since fitted
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