Excessive blowby

[maybrfd]

We have recently built several new engines a 470, and two 505 builds using similar but slightly different piston rod length combinations-all engines using Moroso exhaust evacuation systems.  The 470 was a 0 decked set up using Indy heads and sealed power rings and a 10:7 compression ration; the two 505's one is using shaved/ported Eledbrock heads on a square decked, but slightly out of the "sweet" spot for quench at 11:5 compression, the other is using Eldebrocks and is in the quench.  Of the two 505's one is using an RPM crank with Mahle pistons with standard tension moly rings, the other is a 440 source crank with a shorter rod slightly longer pistons same rings/manufacturer.  All three engines are showing good compression.  We have performed a leak down test on one and it is showing good - 7 lbs loss cold, all cylinders the same, well within "green" condition.  We are getting ready to pull the other 505 to look at leak down on it.    All have the 1/2" oil mod (hemi tube mod) and running high volume pumps with increase oiling mod on bottom end.  One has an oiling mod to run additional oil to the heads through a kit sold by reputable engine builder which blocks oil from the number four bearing and provides it directly from one of the rear galley ports.   All clearances checked out including crank radius, piston ring, pins, ect.  Did not check roughness of final hone by machinist, but looking like pistons seated.   All three show between 60-80 psi pressure at the higher RPMs.  All three engines are experiencing excessive blow by at higher RPMs ( one mushroomed the valley pan - no leaks- pretty cool to see though - thank goodness it wasn't mine:)).

Seen a lot of threads suggesting use of vacuum pump evacuations systems, but gut tells me most are hiding symptom rather than solving problem.  Would like to hear thoughts on potential postulates and suggestions to test:

1.  Higher volume pumps are pushing too much oil in heads blocking crank venting and eventually building enough pressure to blow back
2.  Standard tension rings being smaller and distorting at the higher temperatures/side pressure (piston wobble)
3.  wrong piston/ring combo (even though matched by manufacturer) 

Welcome any and all theories/solutions/discussions.

Thanking all and a have great MOPAR night!
Scott

[69charger440]

ok all!!!

Here is one of the above mention engines. Here we have a 440 source crank (4.150) and rods (6.76). Using Mahle pistons -8cc reliefs on a 1.865 compression height. I took some pictures of two cylinders #3 (Leak down result= 10%) and #4 (Leak down result: 12.5%). Rings looked good, sorry didn't take pictures of pistons and rings before I sent them to Mahle. This motor has less then 100 miles on it. Let me know what you guys think about the wear pattern? Normal? Causing Blow by?  First two picture are of #3 cylinder and last two pictures are #4 cylinder.

[Dmichels]

no not normal
what I see is a piston that got hot expanded and scored the bore
dave

[ws23rt]

Wow-- The valley pan mushroomed? It is hard to imagine the valve cover breathers could not relieve the pressure needed to do that.
It would be interesting to see what a gauge says the pressure is. From the pictures of the bores it looks like they are not very round.
Were they bored and honed with a honing plate?

[ws23rt]

no not normal
what I see is a piston that got hot expanded and scored the bore
dave

I was thinking that as well. But one would think more piston expansion would happen 90% from what we see. It should show up on the piston as well. need more info.

[69charger440]

The piston skirts also have wear on them.. every cylinder and every piston is the same. Piston to wall clearance is at .004

[ws23rt]

We have recently built several new engines a 470, and two 505 builds using similar but slightly different piston rod length combinations-all engines using Moroso exhaust evacuation systems.  The 470 was a 0 decked set up using Indy heads and sealed power rings and a 10:7 compression ration; the two 505's one is using shaved/ported Eledbrock heads on a square decked, but slightly out of the "sweet" spot for quench at 11:5 compression, the other is using Eldebrocks and is in the quench.  Of the two 505's one is using an RPM crank with Mahle pistons with standard tension moly rings, the other is a 440 source crank with a shorter rod slightly longer pistons same rings/manufacturer.  All three engines are showing good compression.  We have performed a leak down test on one and it is showing good - 7 lbs loss cold, all cylinders the same, well within "green" condition.  We are getting ready to pull the other 505 to look at leak down on it.    All have the 1/2" oil mod (hemi tube mod) and running high volume pumps with increase oiling mod on bottom end.  One has an oiling mod to run additional oil to the heads through a kit sold by reputable engine builder which blocks oil from the number four bearing and provides it directly from one of the rear galley ports.   All clearances checked out including crank radius, piston ring, pins, ect.  Did not check roughness of final hone by machinist, but looking like pistons seated.   All three show between 60-80 psi pressure at the higher RPMs.  All three engines are experiencing excessive blow by at higher RPMs ( one mushroomed the valley pan - no leaks- pretty cool to see though - thank goodness it wasn't mine:)).

Seen a lot of threads suggesting use of vacuum pump evacuations systems, but gut tells me most are hiding symptom rather than solving problem.  Would like to hear thoughts on potential postulates and suggestions to test:

1.  Higher volume pumps are pushing too much oil in heads blocking crank venting and eventually building enough pressure to blow back
2.  Standard tension rings being smaller and distorting at the higher temperatures/side pressure (piston wobble)
3.  wrong piston/ring combo (even though matched by manufacturer)  

Welcome any and all theories/solutions/discussions.

Thanking all and a have great MOPAR night!
Scott

1. Oil drains back to the pan faster than the oil pump can pump. If it didn't the pan would empty and pump would suck air.
2. Tension rings as any other rings will distort from expansion only if the ring gap is too small.
3. ??

My is that the bores are not round when the heads are bolted on.
Further there is a line in the bore in the last picture on the right. That would be from a ring end gap. If the bore was wider left to right that would make sense.

[firefighter3931]

The piston skirts also have wear on them.. every cylinder and every piston is the same. Piston to wall clearance is at .004

Inmo. the piston to wall clearance is too tight. I would have set it to .006 for the type of abuse these engines are undergoing. You have to allow for thermal expansion under heavy load and this build has less than one thousandth of an inch for every inch of bore diameter....which is the absolute bare minimum with a forged piston (again inmho). Forged slugs expand but i'm not telling you anything that you don't allready know. 

The damaged skirts are the tell tale sign 

Oddly enough the leakdown results aren't that bad...

Did the piston manufacturer recommend those clearances ?

How tight are the ring end gaps ?




Ron

[69charger440]

The piston skirts also have wear on them.. every cylinder and every piston is the same. Piston to wall clearance is at .004

Inmo. the piston to wall clearance is too tight. I would have set it to .006 for the type of abuse these engines are undergoing. You have to allow for thermal expansion under heavy load and this build has less than one thousandth of an inch for every inch of bore diameter....which is the absolute bare minimum with a forged piston (again inmho). Forged slugs expand but i'm not telling you anything that you don't allready know. 

The damaged skirts are the tell tale sign 

Oddly enough the leakdown results aren't that bad...

Did the piston manufacturer recommend those clearances ?

How tight are the ring end gaps ?




Ron

Ring end gaps were set to .018 top ring .016 second ring. The piston to wall clearance for mahle was .004 -.0049 max. It measured to .004. I measured it after I pulled the pistons and it is at .004.  I am hoping I can save the cylinders by getting new rings and honing with a TORQUE PLATE. I dont think this was done on this motor. Would explain alot.. This also explain why my exhaust ports in the piston where blowing bubbles when I was doing the leak down. Those ports are in the same location of the cylinder wear in the picture. That would explain my 10% leak down on a new motor.

[maybrfd]

The two engines, keep in mind are different.  Scoring seen could be caused by several variables, but agree machining and/or ring/piston/cylinder prep is number 1 culprit.  Second ring should be at higher gap than primary compression ring, alleviates some pressure on primary ring, so potential error here. We'll be pulling carl's next to see.  Carl wants two more races this year, hoping bore scope/tests can give us indications as to whether or not he'll make those or not.  Thanks for those thinking thoughts keep 'em coming.

Ron- appreciate insight on venting - got me thinking about possible back pressure issues with check valves on exhaust venting.

Thx!
Scott

[maybrfd]

I'ld like to hear from some of the more advanced folks out there (know you exist).  One of my issues I am dealing with is we are applying more new technologies to older platforms.  For example  the "sins of our fathers".  In the older days we used cast iron rings which use .125 sizes. this forgave a lot of the out of round bores and provided seating area. Today pistons are lighter, rings are thinners, based upon the newer technologies available (not a bad thing).  In fact Japan is considering a variable ring using composite materials which will allow the ring to be in he .015 or thinner range and be utilized throughout the lower RPM range as a low tension ring, and come in strong at the higher RPM range.  Read further that "plateau" honing is a more desirable finish than the Old theory of ridge (diamond) finish for the newer thin set rings.  Mahle stated that for this particular ring set they are looking for a rougher "ridged" 20-25 RA finish.

I'm thinking that the last three builds are due to imperfections in the machining process based upon past practice/thought, and perhaps we should be applying more exacting criteria in oiling, piston/ring selection and machining process than in the past.  My guess on this particular engine is they did not really use a torque plate and engine builder did not use the "trust, but verify" approach.

To emphasize the above, received an E-mail today from Melling - basically stated the oil pumps they provide are so old the do not have pump curves for them; really- how can you design from an unknown?

Yes , had a few beers and needed to vent - heard someone vented a beer can on his engine earlier this evening:)

To all a good MOPAR goodnight.

Thx!
Scott

[justcruisin]

The piston skirts also have wear on them.. every cylinder and every piston is the same. Piston to wall clearance is at .004


Were they 4032 or 2618 pistons?

[firefighter3931]

Ron- appreciate insight on venting - got me thinking about possible back pressure issues with check valves on exhaust venting.

No Problem Scott ! What got me thinking about the venting issue was a test we did on my 572 while it was on the dyno ; we used 2 different valvecovers with different breathers to see if there could be a difference and there was. 

The driver bank had the fabbed sheet metal VC with the Moroso stack/open element breather and the passenger side had a Chrome Moroso cover with a push on breather bottom vented. The driver side was nice and dry while the passenger side VC was covered in oil mist after a few power pulls. We swapped in a twist on stack and open element breather and no more oil mist. 

Not saying that is entirely your issue here but inadequte venting could certainly be contributing to the excessive crankcase pressure buildup. 

Looks like to me there are a few issues ;

-bores too tight ; not enough piston to wall clearance
-bores not honed with a deck plate which will only aggrivate the tight piston to wall clearance
-gap on 2nd ring too tight
-possible issue with cross hatch angle/finish not matching ring manufacturer specs/requirements

Personally, i don't believe it's an oil pressure/oil control issue. Mine has 80 psi cold with a dual line external setup using a Charlies pan and HV63 pump. It works fine, has lots of pressure, even when up to operating temp and no issues with blowby.

My thinking is that a big cube/high rpm build is going to build more crankcase pressure than your basic 440 so venting becomes more difficult and care needs to be taken when configuring that part of the build. My experience on the dyno supported that train of thought and it was nice to see it with my own two eyes. Seeing is believing as they say 




Ron

[Challenger340]

Humour me here.....JUST ANOTHER "IDEA" FOR YOU TO CHECK.
1.) Do a very close visual inspection of the Moly facing on the two thin OIL Control Rings.....get them in just the correct lighting...let me know if you see high spots(shiney areas) speced by duller sections ?
2.) is the underside of the 2nd compression ring sharp enough for you to SHAVE with ?
* get where I am going with this...?
* Yeah, the Compression Rings may very seal under positive compression like with a leak down....but how well do they SEAL  when FLOODED with lubrication under operation ?
3.) Did any of them run long enough to foul plugs ?

If you have any of the above...and got the rings last year....I just had this problem on a HEMI(as did others)...I think I have the answer for you in this Fawked up outsourced market where Rings from one manufacturer...
are actually from another...
who got them from another...
who actually when you get right down ton it...
don't make it either ?

And in my case...I was using Diamond....who buy from Total Seal...who buy from Hastings...who you guessed it ....outsourced from "where" they wouldn't say.

The reason you are merely seeing it on the Cylinder Bore thrust areas.....and mimicking a "too tight" condition where none might exist... is due to the Piston Cam Ground effect expansion being the only area ......where the Oil Ring Moly FACING overlay INCONSISTENCIES are FORCED against the Bore.

Capeche ?

just my thoughts....see if ya can shave with the underside of the 2nd ring for confirmation.

Take a dial bore gauge, check the cylinders for O.O.R. & Straight, measure Clearance to the Piston Skirt, then if OK, re-hone with a JHU625/ JHU820 W/Brushes Plateau, then get new Oil Rings installed on the pistons...
Oil the Cylinders...
and "by hand" pull the new Oil Rings(on the Pistons) through the Cylinders making sure they SCRAPE the Oil Off before re-assembly.

If you still see grooves in the Oil....more bad Oil Rings,
or,
should I say "Inconsistent Moly Facing application" on the Oil Control Rings.
It happens...somebody forgets... or fawks up the catalyst application prior to the rings going in the booth where the Moly Facing adheres, and PRESTO....lumpy Oil Ring faces that don't scrape squat.  

[Challenger340]

It ain't for lack of a T/plate.....those manifest themselves when seen....as typically "windows" in the crosshatch at the top of the Bore next to where the fasteners excert load on the deck.

That, IMO, from the photos(but hard to see for sure), does NOT look like a plateau finish....certainly not like I do here or have seen from elsewhere ?? especially for after having being run ?

Looks more like a JHU525 Stone straight up ? Apologies, no offense ?

[Cooter]

So Challenger340, What you basically saying (As I think I got a 440 doing this with Good ole Cast rings and mushrooming the valley pan), is that many rings today are "Cheap Japanese Junk"?

[ws23rt]

Ron- appreciate insight on venting - got me thinking about possible back pressure issues with check valves on exhaust venting.

No Problem Scott ! What got me thinking about the venting issue was a test we did on my 572 while it was on the dyno ; we used 2 different valvecovers with different breathers to see if there could be a difference and there was. 

The driver bank had the fabbed sheet metal VC with the Moroso stack/open element breather and the passenger side had a Chrome Moroso cover with a push on breather bottom vented. The driver side was nice and dry while the passenger side VC was covered in oil mist after a few power pulls. We swapped in a twist on stack and open element breather and no more oil mist. 

Not saying that is entirely your issue here but inadequte venting could certainly be contributing to the excessive crankcase pressure buildup. 

Looks like to me there are a few issues ;

-bores too tight ; not enough piston to wall clearance
-bores not honed with a deck plate which will only aggrivate the tight piston to wall clearance
-gap on 2nd ring too tight
-possible issue with cross hatch angle/finish not matching ring manufacturer specs/requirements

Personally, i don't believe it's an oil pressure/oil control issue. Mine has 80 psi cold with a dual line external setup using a Charlies pan and HV63 pump. It works fine, has lots of pressure, even when up to operating temp and no issues with blowby.

My thinking is that a big cube/high rpm build is going to build more crankcase pressure than your basic 440 so venting becomes more difficult and care needs to be taken when configuring that part of the build. My experience on the dyno supported that train of thought and it was nice to see it with my own two eyes. Seeing is believing as they say 




Ron

Ron   I'm interested in the question about crankcase pressure.  It's hard for me to imagine a pressure high enough to bulge the valley pan without escaping the breathers.
Have you had the opportunity to check the pressure under higher rpm?
I Imagine even with a windage tray there is a lot of oil mist going on in there and it will move where the air flows.
I have an oil catch can for this on my challenger to help keep the oil mist from going back through combustion but my instinct says the pressure is near atmosphere and not close to what would be needed to mushroom the valley pan. (even 1-2 psi seem like something the breathers can handle.)

[firefighter3931]

Ron   I'm interested in the question about crankcase pressure.  It's hard for me to imagine a pressure high enough to bulge the valley pan without escaping the breathers.
Have you had the opportunity to check the pressure under higher rpm?
I Imagine even with a windage tray there is a lot of oil mist going on in there and it will move where the air flows.
I have an oil catch can for this on my challenger to help keep the oil mist from going back through combustion but my instinct says the pressure is near atmosphere and not close to what would be needed to mushroom the valley pan. (even 1-2 psi seem like something the breathers can handle.)

I haven't measured crankcase pressure but have seen the ballooned valley pan before. Usually results from inadequate venting under extreme conditions. I'm thinking the filter media gets clogged up and creates a lot of internal pressure and then oil starts pushing past the seals and eventually the pan mushrooms. 

The open element breathers seem to work great and that's my preferred method  from here on out. 


Ron

[Challenger340]

So Challenger340, What you basically saying (As I think I got a 440 doing this with Good ole Cast rings and mushrooming the valley pan), is that many rings today are "Cheap Japanese Junk"?

I can't say anything of the sort Cooter, basically or otherwise ? Just that I still don't know WHO built the Oil Rings after going through 3 Companies ?
And I have no idea on your particular deal either ?
Seems strange to me too...that a good old cast ring set would leak
All I DO KNOW...OR SAID...
is regarding a similar Oil Ring problem I had...is that Oil Ring Leakage CAN cause the Compression Rings not to seal(Blowby), which can in turn exacerbate, or create an excessive Crankcase pressure problem...and unseating other Ringsets(chain reaction sort of) in the Engine causing excessive Blowby.
You can usually SHAVE with the underside of the offending 2nd Compression Ring on the offending Cylinder.
and,
that if I call the Company who supplied them(Oil Rings)....
and I get offed to another Company where the first Company accessed them....
who they then in turn off me to another company...where the second Company got them...
and THAT Company... who WILL NOT confirm they themselves manufacture them, nor tell me who does ?....one can make any assumption from "there" that they wish I guess ?
All phonecalls were rife with the standard "First we've ever heard of it"...and right away followed by..."but we'll gladly send you a new set free of charge"......HUH ?
In my 40 yrs experience Machining and Building Engines, the above is usually a dead giveaway there IS A PROBLEM, just wanna get you GONE with No admissions of a problem,
and especially when...
Hastings don't want the DEFECTIVE part sent back, which I offered on my Nickel so they can confirm what we found with a Dial Indicator Jig on the Mill.... and address any potential manufacturing issues ??
"Nah, no need for that" they said....me again "HUH" ??

Regarding the current problem in this thread....from the photos, it does look suspiciously like a simple Piston Clearance problem, "Scuffing", so that most certainly SHOULD BE the first check with a dial bore gauge in diagnostics..so did mine !! Confounded the shiat outa me !!
but all I am saying is this
if O.O.R., Straight, and Clearance all measures fine.....and WHERE on the Piston that measurement is taken
then as...
just one more thing to CHECK.....have a real close look at the Oil Ring chrome overlay consistency.

All I did to fix mine...was re-hone with same finish, new oil Rings...PRESTO...864hp and ran clean !

I would still like to know...if the one in this threads Photos FOULED any spark Plugs during operation ??
or, if upon teardown...
the underside of the 2nd Compression Ring was sharpened to the point you could SHAVE with it ?

[69charger440]

So Challenger340, What you basically saying (As I think I got a 440 doing this with Good ole Cast rings and mushrooming the valley pan), is that many rings today are "Cheap Japanese Junk"?

I can't say anything of the sort Cooter, basically or otherwise ? Just that I still don't know WHO built the Oil Rings after going through 3 Companies ?
And I have no idea on your particular deal either ?
Seems strange to me too...that a good old cast ring set would leak
All I DO KNOW...OR SAID...
is regarding a similar Oil Ring problem I had...is that Oil Ring Leakage CAN cause the Compression Rings not to seal(Blowby), which can in turn exacerbate, or create an excessive Crankcase pressure problem...and unseating other Ringsets(chain reaction sort of) in the Engine causing excessive Blowby.
You can usually SHAVE with the underside of the offending 2nd Compression Ring on the offending Cylinder.
and,
that if I call the Company who supplied them(Oil Rings)....
and I get offed to another Company where the first Company accessed them....
who they then in turn off me to another company...where the second Company got them...
and THAT Company... who WILL NOT confirm they themselves manufacture them, nor tell me who does ?....one can make any assumption from "there" that they wish I guess ?
All phonecalls were rife with the standard "First we've ever heard of it"...and right away followed by..."but we'll gladly send you a new set free of charge"......HUH ?
In my 40 yrs experience Machining and Building Engines, the above is usually a dead giveaway there IS A PROBLEM, just wanna get you GONE with No admissions of a problem,
and especially when...
Hastings don't want the DEFECTIVE part sent back, which I offered on my Nickel so they can confirm what we found with a Dial Indicator Jig on the Mill.... and address any potential manufacturing issues ??
"Nah, no need for that" they said....me again "HUH" ??

Regarding the current problem in this thread....from the photos, it does look suspiciously like a simple Piston Clearance problem, "Scuffing", so that most certainly SHOULD BE the first check with a dial bore gauge in diagnostics..so did mine !! Confounded the shiat outa me !!
but all I am saying is this
if O.O.R., Straight, and Clearance all measures fine.....and WHERE on the Piston that measurement is taken
then as...
just one more thing to CHECK.....have a real close look at the Oil Ring chrome overlay consistency.

All I did to fix mine...was re-hone with same finish, new oil Rings...PRESTO...864hp and ran clean !

I would still like to know...if the one in this threads Photos FOULED any spark Plugs during operation ??
or, if upon teardown...
the underside of the 2nd Compression Ring was sharpened to the point you could SHAVE with it ?

The plugs looked great! never fouled any out. The motor ran really strong, just couldn't get the rear main to seal up. I measured the cylinder was in three places, top, middle, and bottom. Measured the piston at the skirts. The clearance came out .004, so I left it alone. But I guess Mahle's recommendations are a little to tight. I am going to send it to a machinist to get it honed out and see if I can put another set of rings on and run it. Hope it all goes well.

[Challenger340]

OK, if no plugs fouled...forget Oil Rings.

I had to Re-Hone a HEMI today for a new Customer, and I thought about you....so take a look.

Did your Pistons look like this ?
This is what a "too-tight" Piston Skirt scuffing, for the "application" looks like.
NO, I didn't do it originally...I just get PAID to re-Machine it "properly" for the Guy.

I also tried to get a shot of the JHU820 W/Brushes finish, albeit not good.
Yes, that's a Torque Plate laying next to it in the 2nd shot, make SURE your guy has one !
I gotta wash it tomorrow as I am done...so if you want I'll take a better shot of the bore finish so you have a reference for next time.

[69charger440]

OK, if no plugs fouled...forget Oil Rings.

I had to Re-Hone a HEMI today for a new Customer, and I thought about you....so take a look.

Did your Pistons look like this ?
This is what a "too-tight" Piston Skirt scuffing, for the "application" looks like.
NO, I didn't do it originally...I just get PAID to re-Machine it "properly" for the Guy.

I also tried to get a shot of the JHU820 W/Brushes finish, albeit not good.
Yes, that's a Torque Plate laying next to it in the 2nd shot, make SURE your guy has one !
I gotta wash it tomorrow as I am done...so if you want I'll take a better shot of the bore finish so you have a reference for next time.

Yes piston skirts had wear on them. So your saying I should be able to put a fresh hone on the cylinder walls and new rings and run it? That is what I am hoping.

[maybrfd]

All,

Thanks some good discussion starting to flow.  We plan to pull second motor this weekend.  Will add photos of blown valley and try to get some bore scope photos/videos.  Again, Carl wants to get two more races this year.  so may or may not go further, depending upon what we see.

Last race night went visiting a lot of MOPAR guys to look at venting systems, engine set ups, and oiling Mods. 

Venting - all of the guys running strokers and wet sumps are experiencing excessive crank pressure (different from blow by).  Most solutions varied anywhere from open venting and an occasional wipe down, to low tension ringing with vacuum/catch cans, vacuum with catch cans, exhaust venting, and the good old PVC/vent on some of the smaller engines.  One unique set up was using welded riser vents with hoses to a vented catch can.  One guy was venting back into his oil pan (wasn't too endeared with this fellow).

Based on this and the ring/piston, potential machining issues seen above; knowing this is third one I have seen with venting/crankcase pressure issues; and listening to all of the guys at the track (two were engine builders) - decided more homework is required.  Currently rereading "Stone" and a few other engine design books and any and everything I can find on subject.  What I know so far:

1.  Wet sump systems with strokers all have this issue
2.  Issues is caused by both the crank itself, and piston/oil windage/oil pressure
3.  Leak down and compression tests are inadequate to show dynamic at higher pressure levels associated with the combustion/expansion/exhaust cycles at higher RPMs ( both tell you things, but both are static test)
4.  Equations (crankcase pressure) are linear at lower RMPs
5.  Equations and models vary significantly at higher RPMs and are non-linear

If any of you have any good engine design references or ASME/ASCE or other technical references on subject (crankcase pressure and blowby) please send in my direction.  IF not have site set up for the Scott build a new engine fund 

Have a great MOPAR day!   

[Challenger340]

All,

Thanks some good discussion starting to flow.  We plan to pull second motor this weekend.  Will add photos of blown valley and try to get some bore scope photos/videos.  Again, Carl wants to get two more races this year.  so may or may not go further, depending upon what we see.

Last race night went visiting a lot of MOPAR guys to look at venting systems, engine set ups, and oiling Mods.  

Venting - all of the guys running strokers and wet sumps are experiencing excessive crank pressure (different from blow by).  Most solutions varied anywhere from open venting and an occasional wipe down, to low tension ringing with vacuum/catch cans, vacuum with catch cans, exhaust venting, and the good old PVC/vent on some of the smaller engines.  One unique set up was using welded riser vents with hoses to a vented catch can.  One guy was venting back into his oil pan (wasn't too endeared with this fellow).

Based on this and the ring/piston, potential machining issues seen above; knowing this is third one I have seen with venting/crankcase pressure issues; and listening to all of the guys at the track (two were engine builders) - decided more homework is required.  Currently rereading "Stone" and a few other engine design books and any and everything I can find on subject.  What I know so far:

1.  Wet sump systems with strokers all have this issue
2.  Issues is caused by both the crank itself, and piston/oil windage/oil pressure
3.  Leak down and compression tests are inadequate to show dynamic at higher pressure levels associated with the combustion/expansion/exhaust cycles at higher RPMs ( both tell you things, but both are static test)
4.  Equations (crankcase pressure) are linear at lower RMPs
5.  Equations and models vary significantly at higher RPMs and are non-linear

If any of you have any good engine design references or ASME/ASCE or other technical references on subject (crankcase pressure and blowby) please send in my direction.  IF not have site set up for the Scott build a new engine fund  

Have a great MOPAR day!  

I dunno what to say here ?

I won't waste any more bandwidth here as I have no real ideas to help you ??
but before I go...
and certainly no wars wanted...although I applaud the research you are undertaking on Crank Windage/Venting/Blowby, as they affect each other...I gotta say... I honestly know of no excessive "issue" you speak of that many are experiencing ??

Other than the one HEMI Engine, where I will have to extract my size 13 shoe from my yap, for posting here, and for admittedly "jumping the gun" thinking someone else might be experiencing the same... VERY RARE.... oil Ring OVERLAY inconsistency problem that we experienced......gotta be more out there ??
we just have NOT experienced any excessive Blowby problems EVER ??

Most of ours are 800 to 900hp plus Strokers, quick 16, Comp Eliminator, etc., etc., yes even Brackets Engines down around 550-650hp
even,
572 inch, plus 900hp N/A, Pump Gas, all Aluminum HEMI's driven on the Street ...with one simple PCV Valve and a Breather !!

We've just never had a problem with anything I would consider "excessive"...never even with just push-in open Breathers....NEVER even any "wiping" required on V/Covers other than for periodic detailing ??

Yes, many of the Brackets guys run pan-evac systems...with some of the faster 8-9 second guys will use actual vacuum pumps...for more power.....yes we have seen up to 30hp on the Dyno with the Negative Crankcase Pressure.....
but even ALL THOSE Engines have LITTLE to NO NOTICEABLE BLOWBY @ rpm.....nor even at idle with a simple PCV Valve is plumbed, even with LOW Vacuum on the Big duration bumpsticks ??

Long story short here.....
We Machine & Build as Big....and as Powerful... BB Mopars....Las Vegas "Mopars at the Strip" Winners..... as pretty much anybody out there,
and,
although I have HEARD about inflated Intake Valley Pans from Blowby.....I have actually NEVER seen or experienced ONE myself.....
little-lown TWO
or THREE
in a Row
I FEEL YOUR PAIN HERE !

look, I am not diss'ing anybody...lord knows no mileage for me wasting my time posting here ?? nor can I offer any help for you..my apologies
Just saying....
If it waddles...and quacks...and has Feathers....I call it a Duck
IMO,
Cylinders that are
STRAIGHT.... within .0002", yes....within two Ten-Thousandths top to bottom in the Ring travel
ROUND....within .0005" or less, yes, ....within Five Ten-Thousandths top to bottom in the Ring travel
Done with a Torque Plate
and provided...
1.)  "correct" Piston to Wall clearance as a stable "platform" for the Rings to seal... without excessive Piston "Rock" which de-stabilizes Ring Seal
2.) adequate and correct cylinder Bore Finishes are provided for Rings to seat & seal(use a profilometer)
3.) Ring Endgaps are maintained for the application
That neither...
You..... nor any of these other guys.... should be experiencing this EXCESSIVE Blowby either ??


There, now I have said it.....Jinxed myself.....now, we'll start having "Mystery" BlowBy issues.

[ws23rt]

This topic is interesting to me cause I have a need to know how and why things work.

Before this discussion I had never heard of crankcase pressure as being a problem. The breathers on the valve covers are not called exausters.
I always thought of them as vents.

So here is how my mind works on this. Suppose you connected air to an assembled engine crankcase with a flow meter and pressure gauge. Now start adding air with a regulator until the valley pan starts to bulge. My instinct tells me that one could hear and feel much air coming from the breathers.
Without testing this I don't know what the CFM or the pressure would be needed to cause the valley pan to bulge. Since the pan is concaved to start with just adds to the pressure needed.

So whatever that pressure and CFM is would have to come from blowby. What else could it be?
If that were the case than that is a lot of blowby.

I am now sitting inside the crankcase while the engine is running hard. I look around and see much oil mist. It is rather hot. I smell gas.
It's nice and comfy my ears are not popping from pressure but the wind is blowing alot. While I am waiting for the pan to bulge I light a cig. OOps.

A friend once was testing for spark with a spark plug. He grounded it to an open breather and boom. It blew out seals and gaskets. In this case he had been cranking the engine a lot and there was gas vapor in the crankcase.

Another memory I have--- I was checking out a just rebuilt gearbox. (Industrial speed reducer the-size of a riding lawn mower). The plant was back running. I heard a loud thump that was an explosion inside the gearbox. The dip stick blew 50 feet to the ceiling.
This was caused by a tight clearance that made heat. The heat made smoke. Boom

I'm just saying