Testing crankcase pressure and blow by

[hrdtail78]

Has anybody performed any test like this with a utube water manometer?  I know this is pretty common on other types of engines.  I was looking at collecting this data for initial heat soak cycles and dyno break in.  The PSB I have read on this is all from Onan.  Since I have no data to compare to I will be looking for win/ loose.

Test:
02 FLT 95 reworked hippo build.  Fresh pistons and cyliders.
SE heavy breather.  Perfect for ease of head breather.
Hose off both breather going to y connector, then to adjustable orifice then to manometer. 

There are different size orifices called out for different engine configs.  Then they want you to go to a chart w/ results.  I am going to adjust the orifice untill smooth reading, then lock into size.


Appreciate any input.

[FLTRI]

...I am going to adjust the orifice untill smooth reading, then lock into size.
Appreciate any input.

We had little luck measuring blowby/crancase pressure using a manometer.
Manometers are fine for steady state measurements but no manometer will have a response fast enough for something like this. Can you say "Blowing Bubbles"?
We have found leakage testing is more valuable. Also putting a balloon to the breather can tell you some down and dirty info.
HTH,
Bob

[rbabos]

Has anybody performed any test like this with a utube water manometer?  I know this is pretty common on other types of engines.  I was looking at collecting this data for initial heat soak cycles and dyno break in.  The PSB I have read on this is all from Onan.  Since I have no data to compare to I will be looking for win/ loose.

Test:
02 FLT 95 reworked hippo build.  Fresh pistons and cyliders.
SE heavy breather.  Perfect for ease of head breather.
Hose off both breather going to y connector, then to adjustable orifice then to manometer. 

There are different size orifices called out for different engine configs.  Then they want you to go to a chart w/ results.  I am going to adjust the orifice untill smooth reading, then lock into size.


Appreciate any input.

I tried something similar years ago. Didn't take long to toss it into the corner. Too spastic to get any really good readings. Bubbles and orfice lag doomed it. I used a needle valve which made it an adjustable orfice but it still sucked. Leakdown is still more accurate in the long run, at least in my experience.
Ron

[hrdtail78]

I get steady reading at steady state. This was heat cycles so.....  It produces 1.6 at first idle.  I had orifice wide open, and when it settle into idle I adjusted.  On second run it produced 1.2-1.4.  Did this for rest of heat cycles. I blame the change on smoother idle. Which is caused by break in. But I would consider that a indirect reading thing.  Might be just a idle temp speed change also. 

Next is a dyno break in.

I'm not throwing it in the corner yet.  It can still help me indicate wet sumping.

[rbabos]

I get steady reading at steady state. This was heat cycles so.....  It produces 1.6 at first idle.  I had orifice wide open, and when it settle into idle I adjusted.  On second run it produced 1.2-1.4.  Did this for rest of heat cycles. I blame the change on smoother idle. Which is caused by break in. But I would consider that a indirect reading thing.  Might be just a idle temp speed change also. 

Next is a dyno break in.

I'm not throwing it in the corner yet.  It can still help me indicate wet sumping.

It might. Pulsing increases as the oil fills the case, but I'm thinking outflow will remain the same since it basically reads leakage past the rings. How dramatic this pusling will show up with restricting orfices might be the issue. Too slow of a response on the manometer might mask what you need to see, as well. Interesting to see what combo you come up with that can definately identify between normal and sumping.
Ron

[hrdtail78]

I look at it this way.  I build an engine for a customer.  I break it in, and dyno tune it.  He goes away with all smiles.  Comes back in 9 month with a problem.  I have data that I can recheck.  CCP, leak down, and blowby.  I have all this data at several steps on getting bike finished.  Yes, I would compare to last test data before it left.

It's got to be better than building.  Downloading a can map.  Perform a couple of WOT pulls.  Collect money, and hope customer never returns.  Thats not the business model I work in.  I prefer to be a true DIY.  Find out myself if this is good data or not.  Guess I wont even bring up how I use this on exhaust and what data that produces.

[FLTRI]

It's great to hear about dyno tuners who actually tune and keep track of their cusotmers.
We typically do leakage analysis, cranking compression, and oil pressure recording.
Haven't seen the need to measure blowby due to leakage test being a good indicator.

Guess I wont even bring up how I use this on exhaust and what data that produces.

Please do!
Bob

[hrdtail78]

Herko blocks are installed into exhaust.  I figure why not take out O2, plug hole, and hook up manometer.  Problem with data is the same I have with the other.  No standard to compare to.  But... this bike does have 2-1 supertrapp so....  Maybe I can give myself headaches changing disc.

[1FSTRK]

 
I like the way you think
Gather the data, the trends will show themselves with time.

[rbabos]

Herko blocks are installed into exhaust.  I figure why not take out O2, plug hole, and hook up manometer.  Problem with data is the same I have with the other.  No standard to compare to.  But... this bike does have 2-1 supertrapp so....  Maybe I can give myself headaches changing disc.

I like that idea on the discs and back pressure data.
Ron

[BB]

I have run engine on dynos for years.Ever size from 2 cylinder HD to 18 cylinders with over 6" bore . I have always monitored crankcase pressure (blow-by).It is a small thing to do , but can catch a problem in the early stages if you are having a failure .It is directly relatered to how well the rings are seating and valves .If pressure is high you can stop the dyno run and find the problem before it is a big problem and cost a lot of $. You will see it on crankcase psi change  before air fuel , oil pressure , temperature of engine and probably exhaust temp.I my oppion watching blow-by is a very good thing to watch.The more data a guy can find the better the engine builder / tuner he will be . You may find later it is not important , but some day a bike will come in with a problem and the data you have learned by tyring new things and different thing might help  fix that problem . And the customer will say " Man you know some stuff". :hyst:Don't ever stop learning.Good luck!
Buddy

[FLTRI]

Well put!! 
Bob

[hrdtail78]

I'm reading upstream of the PCV valves.  As a rethought I am going to tie into the share hose from engine to oil sump.  As somebody did suggest reading it with a modified oil cap.  If the gauge can be made responsive enough I could see how sumping can be detected this way.