Milwaukee Midget

[jacksoni]

You are not going to get lift/degree from anyone I don't think-   Very, very unlikely . . . . .  this is considered proprietary information.

cam DR it or measure by hand- which I have done time to time and is a PITA but some programs can take that data as a notepad set and make curves from it. ( I have one of those but is lot more work to put stuff in)

Cam Analyser from Performance Trends can accept hand accumulated data via hand entry into the program for analysis.  It can also import data from other cam measuring programs, as well as data in a spreadsheet format.   There are several versions with increasing capability.  For details see:

http://performancetrends.com/download.htm#ca

Some caveats about cam profiling:
A)   More information is always better, hence the PITA nature of hand data accumulation/hand entry.   Measurement at intervals of 2 degrees of crank rotation is best, lots of work and data points.    By hand, lots of opportunities for errors.    Need to work carefully.

2)   Compared to measurements taken by high resolution encoders, hand accumulated data accuracy suffers.  It is not accurate enough to analyze acceleration and jerk.

d)   The accuracy by hand is good enough if you are careful, and you just want to analyze displacement and maybe velocity data.    You save yourself $2K over purchasing a complete entry level measurement setup.    You should be able to find a shop with a Cam Dr. or a Cam Pro who will test the cam for you for about $125.    You should get a written report for this charge, not just a detailed cam card.   Expect to pay more to test every lobe and get a detailed analysis.
 
Fordboy

I want to illustrate this with a couple of screen shots but my computer skills are failing me. Will post each separately. One is curves generated by entering data from a cam card in a program which spits out lift, velocity acceleration and jerk curves. The second is from hand generated data measuring 340+ points at every degree engine rotation reading lift with a digital dial indicator on the lifter. You can see the result, thus Fordboy's comments.

[jacksoni]

screen shot 1

[jacksoni]

and two

[Rex Schimmer]

I attended a seminar provide by Dema Elgin on engine design several years ago and one of his guest speaker was a gentleman that ground cams for the Joe Gibbs Racing Team. He related that he made two cams that had exactly the same lift, timing etc but one cam had 5 ten thousands of an inch (that's .0005 inches) difference in the flank dimensions. That cam would turn an additional 600 rpm and produced 10 hp more than the other "identical" cam. There is a lot of dynamic "physics" going on when you start turning 9000 rpm+ and looking for that last horse power. My guess is that many cam grinders would have a "challenge" just trying to maintain a .0005 inch tolerance much less be able to actually grind cams to that type of tolerance and then discern the performance difference.

Rex

[fordboy628]

screen shot 1

Don't know how much input info was required to generate this set of curves.   Looks like a "perfect" scenario generated with minimum info and maximum "smoothing".

[fordboy628]

and two

And this is obviously the hand accumulated data.    Reference my original comment.

Sometimes you just need access to the "good" tools.
 
Fordboy

[fordboy628]

I attended a seminar provide by Dema Elgin on engine design several years ago and one of his guest speaker was a gentleman that ground cams for the Joe Gibbs Racing Team. He related that he made two cams that had exactly the same lift, timing etc but one cam had 5 ten thousands of an inch (that's .0005 inches) difference in the flank dimensions. That cam would turn an additional 600 rpm and produced 10 hp more than the other "identical" cam. There is a lot of dynamic "physics" going on when you start turning 9000 rpm+ and looking for that last horse power. My guess is that many cam grinders would have a "challenge" just trying to maintain a .0005 inch tolerance much less be able to actually grind cams to that type of tolerance and then discern the performance difference.

Rex

Rex,

Well, measured where?

A dimensional difference of .0005" somewhere on the cam wouldn't make that much difference to the running of the engine.    It simply wouldn't affect the displacement or velocity curves that much.

However, a difference of .0005" of flank velocity per degree of cam rotation would be a pretty big difference in velocity.   That would have the type of impact you describe.   Even with the cam lift equal and timing figures @ .050" lift equal, these would be very different cams, due to the differences in velocity and the other derivatives.

"Good" cam people are grinding to tolerances of .00005"  or less, with computer controlled machines.   The calculations for manufacturing the masters (what controls the grinding process) are calculated to 6 figures.    This may be moot on engines where the power extraction is not to the N'th degree.    But for professional race teams, it does matter.

And yes, the dynamics of cam/valve train motion is challenging.    Especially if you want to control the valve train, and keep it reliable.
 
Fordboy

[jacksoni]

and two

And this is obviously the hand accumulated data.    Reference my original comment.

Sometimes you just need access to the "good" tools.
 
Fordboy

exactly the reason why I posted these to  illustrate your point!

[fordboy628]

I want to illustrate this with a couple of screen shots but my computer skills are failing me. Will post each separately. One is curves generated by entering data from a cam card in a program which spits out lift, velocity acceleration and jerk curves. The second is from hand generated data measuring 340+ points at every degree engine rotation reading lift with a digital dial indicator on the lifter. You can see the result, thus Fordboy's comments.

Jacksoni,

Just out of curiosity, what program generated this graphic output?
 
Fordboy

[jacksoni]

I want to illustrate this with a couple of screen shots but my computer skills are failing me. Will post each separately. One is curves generated by entering data from a cam card in a program which spits out lift, velocity acceleration and jerk curves. The second is from hand generated data measuring 340+ points at every degree engine rotation reading lift with a digital dial indicator on the lifter. You can see the result, thus Fordboy's comments.

Jacksoni,

Just out of curiosity, what program generated this graphic output?
 
Fordboy

Input data includes EVO,EVC, lift, Open/Close ramp lift ratio (program makes suggestions), Open/Close ramp duration ("major intensity" as I under stand and some grinders will give you this but program makes suggestions as well),lobe dwell duration and is max lift centered on the lobe.

The software is Vannik's EngMod4T suite. Lot of development capability and detail and so of course lots of area for GIGO. I have heard some engineers whose opinion I respect say they think is pretty good. Not in the multithousand dollar range.
http://www.vannik.co.za/index.htm  Are you familiar with it?

[Jack Gifford]

jacksoni- thanks for posting the graphs. My own hand-recorded (and calculated) graph data of velocity & acceleration hasn't been nearly as "noisy" as your example (maybe 7 - 8 different lobes over the years). It's been of sufficient quality to confirm my requests to the cam-grinders to not exceed certain peak-negative-acceleration values. Here's a copy of a portion of such an acceleration graph (cam only read at 5 degree intervals).

[jacksoni]

I think part of my problem goes to trying to measure every 1* and the inherent difficulty being accurate in the entire process as Fordboy has pointed out. He mentions going to 5/10000" while I am maybe at .05MM accuracy. Big difference. the program I was using will import electronic files as from a Cam Dr or Cam pro so they should be a lot more representative of reality.

[Milwaukee Midget]

Here's a thought.

Of course, using an automated, motorized cam checker will always get you the most reliable reading, because it's virtually infinite in its input-output readings.

But one of the other advantages is that it automatically minimizes slack between the fixture and the measuring plunger.

I'm wondering if making a complete revolution of the cam for each degree of measurement might not smooth out the reading. 

There's likely an infinitesimal amount of slack between the cam and the fixture that could be minimized by always coming up on the lobe in the same direction and from an equal distance.

Think torque wrench.

Or think guitar.

On a guitar, you want to tune "up" to the pitch, not take it down.  This keeps the attack of the tolerances constant in the tuning keys with respect to your measurement (pitch of the string). 

If you approach the lobe measurement with the same idea, you would advance the lobe 361 degrees, take your measurement, advance it another 361 degrees, etc., keeping the attack of the tolerances always on the same relative side of the fixture. 

Huge difference?  On an acceleration flank, I think maybe so.

[jacksoni]

Here's a thought.

Of course, using an automated, motorized cam checker will always get you the most reliable reading, because it's virtually infinite in its input-output readings.

But one of the other advantages is that it automatically minimizes slack between the fixture and the measuring plunger.

I'm wondering if making a complete revolution of the cam for each degree of measurement might not smooth out the reading. 

There's likely an infinitesimal amount of slack between the cam and the fixture that could be minimized by always coming up on the lobe in the same direction and from an equal distance.

Think torque wrench.

Or think guitar.

On a guitar, you want to tune "up" to the pitch, not take it down.  This keeps the attack of the tolerances constant in the tuning keys with respect to your measurement (pitch of the string). 

If you approach the lobe measurement with the same idea, you would advance the lobe 361 degrees, take your measurement, advance it another 361 degrees, etc., keeping the attack of the tolerances always on the same relative side of the fixture. 

Huge difference?  On an acceleration flank, I think maybe so.

To be honest, I am not sure how this would help but making it even more a PITA rotating the whole shebang 361 every time rather than just 1 doesn't sound too swell. I think my error trying to read every degree rather than 2 or 5 as has been suggested might have made the software go a bit batty as the curves show. Anyway, I did this just to try if the program predicted anything different with the generated curves rather than the measured curves. Has been too long, I don't remember. Got CRS. 

[fordboy628]

Input data includes EVO,EVC, lift, Open/Close ramp lift ratio (program makes suggestions), Open/Close ramp duration ("major intensity" as I under stand and some grinders will give you this but program makes suggestions as well),lobe dwell duration and is max lift centered on the lobe.

The software is Vannik's EngMod4T suite. Lot of development capability and detail and so of course lots of area for GIGO. I have heard some engineers whose opinion I respect say they think is pretty good. Not in the multithousand dollar range.
http://www.vannik.co.za/index.htm  Are you familiar with it?

I am aware of it, but have not used it.

There are some guys I know who are using it, (they are Euro-guys) and they also evaluate it favorably.   The usual comment is that it is not as complex as more expensive software.    As in waaay more expensive . . . .

Having said that though, I think that $500 USD is about the ceiling of what non-pro racers are willing to invest in engine modeling software.    And at that price point there are going to be less features than programs that cost 20 or more times that price.

In my consulting business I am using Performance Trends software packages.    There is always a need to import/export data from one analysis program to another, and Performance Trends allows seamless data import/export from one package to another.    This is important to me.

I'm just getting started with E/A Pro, after years of using more expensive software.    Once I evaluate the output, I'll post up what I think.
 
Fordboy