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Case pressure data

Started by hrdtail78, November 27, 2021, 06:11:29 AM

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hrdtail78

November 27, 2021, 06:11:29 AM Last Edit: November 27, 2021, 06:52:39 AM by Ohio HD
This is a screen shot from a data log that has recorded crank case pressure.  Just using a 3 bar map sensor in the crank case at the location of a evo timing plug and recorded at 1000 frames a second with a stand alone ECU.  The sensor puts out a voltage and the ECU displays it in kpa.  With a math channel I have it converted to psig for easiest understanding.  This is at idle on a 135 cubic inch engine, 15:1, 2003 trans with stock oil pan.  This engine has modified breathers out of the boxes and has inline check valves breathing to atmosphere through catch can. 

I won't be posting the data log because when you do send the data log.  The calibration the log was made from is also attached.  So screen shots it is. 

You can clearly see that for every time the pistons go up.  We are creating lower than atmosphere pressure and when piston goes down.  We get some pressure.   


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Semper Fi

hrdtail78

November 27, 2021, 06:12:20 AM #1 Last Edit: November 27, 2021, 06:53:27 AM by Ohio HD
This one is a wot pull.  You can see that we still see a vacuum and pressure but not as high for either. 



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Semper Fi

Don D

What are your thoughts and conclusions based on the data?

turboprop

This is really cool information. I pay attention to a lot of things but do not recall anyone ever sharing anything close to clinical data like this.

To take this a step further would be to show the pressure trace along with traditional Hp & Tq traces with various case venting configurations.
'We' like this' - Said by the one man operation.

hrdtail78

This isn't what I would call a typical engine.  It came with several different breather options.  Breather out each head, option breather out of cam chest and crank cavity.  I did several configs, including a hole in oil fill with no check valve.  I found best case pressure and power with head vent only w/ pcv device.  This data was collected on the dyno.  Maybe if I can find the can protocol for winpep8.  I can send the output to it and I could overlay w/ hp and tq. With my dyno.  There really wasn't much readable, noticeable difference in power, I don't believe all mods can be read with my 250i, but tenths of a second counts for this customer.

One thing I get out of this that can be seen in the wot run is this.  See where case pressure doesn't track like the rest.  What can disturb ring seal and case pressure? 
Semper Fi

hrdtail78

Quote from: HD Street Performance on November 27, 2021, 06:23:25 AMWhat are your thoughts and conclusions based on the data?

Basically that your crank does see a vacuum, a pcv device is helpful with this and you don't need 4-5 pressure outlets at 3/8 ID on a NA engine at least. 
Semper Fi

itsafatboy


great info ,  so here is some more I have a 116" twincam 11.3 comp. setup  what I have done is had the KRANK vents off heads so one way valves also bored the heads breather holes to 1/2" breather like evo instead of the 3/8 twin cam ones ,  this worked great no oil out of heads , I also use SS die cat rocker covers so really no one way valve in rocker box only on breather holes , like I said this worked great,

then I have a R&R cycle 3 piece cam plate/cover setup that allows a external breather to be hooked to cam plate , I ran a line from this to a catch can with no one way valve, so just a line,  the cam plate has a labyrinth to separate air oil this also worked just great not a lot of oil out of the breather line to the catch can but will get some when ran hard.

here is where it got strange I  added a one way valve to the line coming out of the cam chest thinking since i had two off the head breathers then i'll just add one more off cam chest to create negative pressure all around well it filled the catch can at about a 3 mile ride then was dumping oil from the can,

so the head one way valves work great but when you add the third one to cam chest it does not work at all,  i think it sumps the cam chest thats why those S&S crank vents that run behind the cam plate dont work worth a crap just creates sumping , so I am sticking with the krank vents off heads and the line to catch can off the cam plate with no one way valve (keeping this because R&R says it helps stop oil aeration) 

Side note i do like the R&R integrated cam plate/cover setup because the cam plate itsself bolts to every hole on the case for stability its built like a beast also has bushing still and i like that, run it with the thayer pump

       

hrdtail78

Quote from: itsafatboy on November 29, 2021, 01:19:47 PMhere is where it got strange I  added a one way valve to the line coming out of the cam chest thinking since i had two off the head breathers then i'll just add one more off cam chest to create negative pressure all around well it filled the catch can at about a 3 mile ride then was dumping oil from the can,


       

I am not real familiar with that cover besides its available. Does he recommend plugging the head breather when using his cam cover?
Semper Fi

les

Don't you need to be sampling at 2.56 times the fastest rate of the event to prevent aliasing?

hrdtail78

Quote from: les on November 29, 2021, 07:28:49 PMDon't you need to be sampling at 2.56 times the fastest rate of the event to prevent aliasing?


Sure, but this is the equipment I have.  At 6000 rpm's the crank is rotating 100 times a second.  That is 200 strokes per second.  At a data collection rate of 1000 frames a second.  I am reading 5 frames for each stroke.  Got to make the best of my resources.

This post isn't the best presentation of the data collected.  I tested idle, steady state and WOT for 6 different breather configs. This was done for myself and it takes time.  It should be presented as:  Here is config 1, with dyno sheet and CC data at Idle, steady, WOT.  Here is config 2 etc etc.  Getting it together to present it for all takes a lot of time.  Plus during this testing.  A calibration for a 135 cu in, 15:1, 700 plus lift cam, on race fuel had to be created from scratch as break in occurred.  Probably not the best platform but one take away from this.  Engine has good ring seal.
Semper Fi

Don D

In my minds eye I have always thought that there is internal pressures and differentials by design to help move the oil back to sump and control aeration. In other words theoretical 0 pressure or vacuum in the space limited dry sump system may not be ideal. Open for comments.

hrdtail78

Quote from: HD Street Performance on November 30, 2021, 08:47:44 AMIn my minds eye I have always thought that there is internal pressures and differentials by design to help move the oil back to sump and control aeration. In other words theoretical 0 pressure or vacuum in the space limited dry sump system may not be ideal. Open for comments.

I don't disagree.  The vacuum in an evo case does help remove oil out of the heads, and pressure helps move it to cam chest for scavenge.  Diverting that oil into the cam chest instead will puke some oil out a bottom breather.  BUT different breathing/ oil system all together. 

Then take a Thayer style pump.  Independently scavenge from crank and cam cavity.  Different all together and more of a true dry sump.

Then the M8 latest oil pump fix with a seal.  Or is it a seal or is it work more like a check valve.  Looking at the design.  I can see how pressure could be allowed to escape into cam cavity.  Maybe only one inner cam bearing also affects this.

Then the S&S TC reed valve.  I never tried one with a Thayer style pump and I have always wondered if it would produce same results as with a simple two stage.

One of the things that I have always wondered about is the capacity of the oil tank.  With the dry sumps in other industries I am familiar with.  Dry sumps in piston pounder aircraft.  If the engine hold 6 quarts of oil.  There is about 5-6 quarts of air volume.  Same can be said about late model dirt track.  Then there is the 3.5 oil tanks that seem to breath out half a quart to find it's own level.  I have always been under the thought that it isn't seeking an oil volume more than it is seeking a certain amount of air volume.  The reason I suggest an extra quart oil pan but don't put the extra quart into it.  More air volume.  I think that goes back to what you are saying?  The larger the air volume the less pressure should fluctuate.  One thing I wanted to test but just ran out of time.  I wanted to splice into the early TC equalizer hose and run that into a sealed vessel a couple of quarts in size to see if the fluctuations went down.  I figure the size as it goes up will have diminishing returns and that could help finding the correct size for something that could be made and permanently attached to the bike.

I will add this because it is something I have thought about.  M8's actually have less air volume than the TC but production engines have more displacement.  For what you are displacing on the top.  I figure you are roughly displacing 70-75% of that on the bottom as well.  (never sat down and did the math on what volume the rod takes up.)  Primary housing is also smaller.  Is this the reason why some have problems with oil carry over from transmission?
Semper Fi

turboprop

Quote from: hrdtail78 on November 30, 2021, 09:38:27 AM
Quote from: HD Street Performance on November 30, 2021, 08:47:44 AMIn my minds eye I have always thought that there is internal pressures and differentials by design to help move the oil back to sump and control aeration. In other words theoretical 0 pressure or vacuum in the space limited dry sump system may not be ideal. Open for comments.

I don't disagree.  The vacuum in an evo case does help remove oil out of the heads, and pressure helps move it to cam chest for scavenge.  Diverting that oil into the cam chest instead will puke some oil out a bottom breather.  BUT different breathing/ oil system all together. 

Then take a Thayer style pump.  Independently scavenge from crank and cam cavity.  Different all together and more of a true dry sump.

Then the M8 latest oil pump fix with a seal.  Or is it a seal or is it work more like a check valve.  Looking at the design.  I can see how pressure could be allowed to escape into cam cavity.  Maybe only one inner cam bearing also affects this.

Then the S&S TC reed valve.  I never tried one with a Thayer style pump and I have always wondered if it would produce same results as with a simple two stage.

One of the things that I have always wondered about is the capacity of the oil tank.  With the dry sumps in other industries I am familiar with.  Dry sumps in piston pounder aircraft.  If the engine hold 6 quarts of oil.  There is about 5-6 quarts of air volume.  Same can be said about late model dirt track.  Then there is the 3.5 oil tanks that seem to breath out half a quart to find it's own level.  I have always been under the thought that it isn't seeking an oil volume more than it is seeking a certain amount of air volume.  The reason I suggest an extra quart oil pan but don't put the extra quart into it.  More air volume.  I think that goes back to what you are saying?  The larger the air volume the less pressure should fluctuate.  One thing I wanted to test but just ran out of time.  I wanted to splice into the early TC equalizer hose and run that into a sealed vessel a couple of quarts in size to see if the fluctuations went down.  I figure the size as it goes up will have diminishing returns and that could help finding the correct size for something that could be made and permanently attached to the bike.

I will add this because it is something I have thought about.  M8's actually have less air volume than the TC but production engines have more displacement.  For what you are displacing on the top.  I figure you are roughly displacing 70-75% of that on the bottom as well.  (never sat down and did the math on what volume the rod takes up.)  Primary housing is also smaller.  Is this the reason why some have problems with oil carry over from transmission?


I used to crew for an AHDRA pro stock team. Our bike and every other bike in the class had a very large pump driven off of the crankshaft that was used to pull a vacuum from the case.

I know of at least two high level race teams that use seal the back bone of touring frames and use it as an expansion tank as you describe. One of them competes in pro level drag racing, the other runs at Bonneville.

The 124" TC engine in my red FXR has the S&S one way valve installed behind a 3-stage oil pump. Miraculously, the world didnt end as a result like so many on this forum proclaimed would happen.

The 124" TC engine in my blue FXR has an AC from HPI that has vent nipples for a smaller size hose. I forget if they are ⅛" or 3/16" ID have nipples. I didn't think those small head vents would work but gave them a try. Miraculously, the world also did not end as a result of the smaller head vents as so many on this forum proclaimed would happen.

I hate to admit it, but am glad you are back posting on this forum and think you are onto something with your research.
'We' like this' - Said by the one man operation.

itsafatboy

Quote from: hrdtail78 on November 29, 2021, 03:33:07 PM
Quote from: itsafatboy on November 29, 2021, 01:19:47 PMhere is where it got strange I  added a one way valve to the line coming out of the cam chest thinking since i had two off the head breathers then i'll just add one more off cam chest to create negative pressure all around well it filled the catch can at about a 3 mile ride then was dumping oil from the can,


       

I am not real familiar with that cover besides its available. Does he recommend plugging the head breather when using his cam cover?

Its the RR cycle 2 piece cam plate , no he doesnt suggest stopping the head breathers at all he just says to run a line no pcv off the polate it helps stop oil airation , so thats what i do now to a catch can it works just fine , the cam plate has a labrynth the air runs through to seperate the oil in the cam plate , the other thing is the cam plate bolts to every case bolt hole so very solid piece ,

http://www.rrcycles.com/shop/cam-support-covers-oil-pumps-c-7_10_14/rr-cycles-2-piece-cam-cover-99-up-p-68.html

Thermodyne

As designed, the top breather will draw a vacuum on the crankcase.  It lets pressure out, put does not allow for air to be drawn back in.  Then, anything that comes out, goes down the suck hole and gets burned.  This was enough to appease the EPA.  Biggest drawback was the limited ability to separate oil from the gasses being pumped out.  And the declining function as the ring seal wears away.

Back in the 90's I put a fuel pressure/vacuum gauge on the breather hose of an evo that had less than 1000 miles on it.  At idle the needle was bouncing around.  But at 50 just cruising, it showed an inch of vacuum.  I've put that same gauge on some high mileage Evo scooters, and it always shows pressure at 50.

In the last couple of years, I've used that gauge on some M8's with oil in the breather.  They all showed pressure at 50mph.  And I put it on two different M8's that did not have oil in the breather, both showed a little vacuum at 50.  These were scooters with less than 5000 miles on them.   

kd

Good real world info.  Thx.
KD

itsafatboy

Quote from: hrdtail78 on November 29, 2021, 03:33:07 PM
Quote from: itsafatboy on November 29, 2021, 01:19:47 PMhere is where it got strange I  added a one way valve to the line coming out of the cam chest thinking since i had two off the head breathers then i'll just add one more off cam chest to create negative pressure all around well it filled the catch can at about a 3 mile ride then was dumping oil from the can,


       

I am not real familiar with that cover besides its available. Does he recommend plugging the head breather when using his cam cover?

No leave the breather off the heads but use krank vents on the banjo bolts , I use ss diecast rocker covers  and if your in the rocker area on stock boxes you can take out the one way breathers in there since you will have them hanging off banjo bolts , the good crank vents are called
Krank vents from ET performance

The cam plate with the oil separation and ability to have a vent line is RR Cycle , it's a grate cam plate and cover kit , super
Strang and bolts to every case
Hole, also has place to put a oil pressure gauge

60Gunner

The krankvents from ET Performance aren't available anymore. Been looking for years. I've found and use reed valves that work quite well. They come in a case mount or in line version. They use a reed valve from BMW twins in a machined housing. Im going to drill and tap where the hose barbs are in the breather bolt spacers and hard mount them.


kd

Quote from: 60Gunner on April 20, 2022, 07:03:36 PMThe krankvents from ET Performance aren't available anymore. Been looking for years. I've found and use reed valves that work quite well. They come in a case mount or in line version. They use a reed valve from BMW twins in a machined housing. Im going to drill and tap where the hose barbs are in the breather bolt spacers and hard mount them.




Isn't there a risk of these BMW reed valves being beyond the head breather valves and lower that they will Change the pressure on the exhaust side to negative and prevent the head breathers from performing their one way function?  If that occurs I can see they will begin to bypass passively and contaminate (with oil) the new reed valve addition via the filter base spacers.  Especially if they are mounted lower than centerline or plane of the head port and the filter base spacers that they will be mounted in.  Fluids (or heavy vapors) migrate down hill.  I am wondering if that possible contamination could cause the reed valves to fail and leak? 

It appears in your pic you have them mounted only not yet hard mounted.  Have you actually run that setup yet?  If so was there any contamination to the BMW component?
KD

Ohio HD

Quote from: kd on April 20, 2022, 07:39:16 PM
Quote from: 60Gunner on April 20, 2022, 07:03:36 PMThe krankvents from ET Performance aren't available anymore. Been looking for years. I've found and use reed valves that work quite well. They come in a case mount or in line version. They use a reed valve from BMW twins in a machined housing. Im going to drill and tap where the hose barbs are in the breather bolt spacers and hard mount them.




Isn't there a risk of these BMW reed valves being beyond the head breather valves and lower that they will Change the pressure on the exhaust side to negative and prevent the head breathers from performing their one way function?  If that occurs I can see they will begin to bypass passively and contaminate (with oil) the new reed valve addition via the filter base spacers.  Especially if they are mounted lower than centerline or plane of the head port and the filter base spacers that they will be mounted in.  Fluids (or heavy vapors) migrate down hill.  I am wondering if that possible contamination could cause the reed valves to fail and leak? 

It appears in your pic you have them mounted only not yet hard mounted.  Have you actually run that setup yet?  If so was there any contamination to the BMW component?

I agree. I would rather the valves are the highest point in the venting system.

kd

Quote from: Ohio HD on April 20, 2022, 07:43:01 PM
Quote from: kd on April 20, 2022, 07:39:16 PM
Quote from: 60Gunner on April 20, 2022, 07:03:36 PMThe krankvents from ET Performance aren't available anymore. Been looking for years. I've found and use reed valves that work quite well. They come in a case mount or in line version. They use a reed valve from BMW twins in a machined housing. Im going to drill and tap where the hose barbs are in the breather bolt spacers and hard mount them.




Isn't there a risk of these BMW reed valves being beyond the head breather valves and lower that they will Change the pressure on the exhaust side to negative and prevent the head breathers from performing their one way function?  If that occurs I can see they will begin to bypass passively and contaminate (with oil) the new reed valve addition via the filter base spacers.  Especially if they are mounted lower than centerline or plane of the head port and the filter base spacers that they will be mounted in.  Fluids (or heavy vapors) migrate down hill.  I am wondering if that possible contamination could cause the reed valves to fail and leak? 

It appears in your pic you have them mounted only not yet hard mounted.  Have you actually run that setup yet?  If so was there any contamination to the BMW component?

I agree. I would rather the valves are the highest point in the venting system.

That was where I was going but I didn't want to pollute an already complicated response.  I actually had it in there at the end but took it out.  It may still have the effect of cancelling out the OEM breather operation but it wouldn't matter so much if they were protected from contamination with elevation for example.
KD

60Gunner

April 20, 2022, 08:10:15 PM #21 Last Edit: April 20, 2022, 08:28:46 PM by 60Gunner
I initially still had umbrellas in. Despite someone testing them for me without umbrellas with great results, it was dyno day and didn't want to risk them being an issue. I chickened out!! The umbrella valves are removed now but the assemblies are still in place to aide in air/oil separation. These ARE the only one way valves I'm using. No more umbrella valves.
I would prefer case mount but for lack of a good location off hand, opted for this. No, they aren't hard mounted yet.
Once my rings seated on the dyno I never got another drop out of them. But a slight vacuum will also aide in the heads draining better in the first place so...
Bottom line is they work quite well as is.
They are pricey tho but the reed valve itself Inside the housing can be replaced for like $35 if it were ever necessary.

https://jsmotorsport.com/js-motorsport-technical-reed-valve-crank-case-breather/

Ohio HD

Many have great results using these inexpensive one way check valves that S&S sells. I'm pretty sure that they come with the S&S crate motors.

I run OEM breathers on my 124" Twin Cam. No problems them them. I all I ever see in the catch can is some dirty water from condensation within the motor. 


50-8122 S&S Cycle



JSD


Quote from: Ohio HD on April 21, 2022, 11:04:09 PMMany have great results using these inexpensive one way check valves that S&S sells. I'm pretty sure that they come with the S&S crate motors.

I run OEM breathers on my 124" Twin Cam. No problems them them. I all I ever see in the catch can is some dirty water from condensation within the motor. 


50-8122 S&S Cycle



I use above with umbrellas  

60Gunner

Looks to be the exact same valve used in Mercedes compressor motors and can be had for $12. I heard they work well. It was on my list of valves to try.
Don't have time this morning to track down the part # but a google search should find it. It too is a reed valve. Any good fast acting reed valve should work well.
The question is how long will it last. The same can be said for any valve including mine.