Cam Test Stand for Cam Analyzer

Electronics and Encoders for Recording Cam Lobe Measurements

Displayed below are 3 screens showing some of the features of the new Cam Analyzer when fitted with our Cam Test Stand (shown below).

Our Cam Test Stand is shown below.  It's encoders measure lift to .00004 inches (4 hundredths of one one thousandth of an inch) and cam rotation angle to .036 degrees.

Click here to view the Cam Analyzer software page, the software which runs the Cam Test Stand.

Main Screen when measuring a lobe.  Note that on the main screen, the layout of the cam is displayed so you know exactly which lobe you should be on for the different cylinder numbers, intake and exhaust.  Also note that the lobes are graphed immediately with each measurement so lobes which are "out of line" can be quickly checked again.

This comparison report shows critical data for each of the 16 lobes on this cam.

  (Click on image to enlarge it)

This graph shows detailed comparison between all lobes on this cam.  You can select to graph only certain lobes or all lobes, and lobes from other cam tests.  You can also select to graph lift, velocity, acceleration, and/or jerk.

  (Click on image to enlarge it)

Plus Version of Cam Analyzer

The Plus Version of the Cam Analyzer adds "high tech" several features to our standard program.  Prior to version 3.8, most of these features were only useful if you have the complete Cam Test Stand.  Now with version 3.8, you can use these features on hand measurements (dial indicator and degree wheel), standard profiles created within Cam Analyzer, and from importing several formats of standard cam files (like Cam Dr ^tm, Cam Pro Plus ^tm, S96, Andrews, Comp Cams, Doctor Dr).  These Plus features include:

Virtual Follower

The Virtual Follower feature lets you measure the cam on the stand without using the actual follower used with the cam.  You will place the linear encoder's pointer directly on the lobe.  See Figures below.  The advantage is you don't need the actual follower or the bore adapter of the correct size for the follower.  For some valve trains, like Overhead Cam systems with Rocker Arms, the Virtual Follower method is the only method available without installing the cam in the engine or head.

Using Actual Follower                 Using "Virtual" Follower
        

Click here for a graph showing the significant difference (error) between measuring the lobe with the pointer only, and how the Virtual Follower simulation converts this data into the true cam profile. 

You will enter the measurements for the flat or roller follower, or overhead cam valve train into the program.  The software will calculate the resulting valve lift, instantaneous rocker arm ratio, contact point on the follower, and much more.  The Virtual Follower feature is currently developed for:

  (Click on image to enlarge it)

You can select to use the same or different Virtual Followers on the intake versus the exhaust cam lobes.    

Accuracy of Virtual Follower

The graph below indicates the typical accuracy of the Virtual Follower to simulate the actual follower for lift and acceleration.   (Acceleration was included as it magnifies differences between lobes.)  Note that we could have come up with graphs of better accuracy.  We purposely used typical data to show that there will always be some difference between the Virtual Follower results and results measured with the actual follower. 

Click here for a "Graph Analyze - Find Difference Between Lobes" report showing the maximum difference found between these 2 cam measurements (Actual and Virtual Follower).  Click here for a "Lobe Comparison" report showing the difference between these measurements for Tappet Lift, Duration, Lobe Separation, etc.  For most of these critical measurements, the difference is less than 0.5%.  For less critical measurements, like peak accelerations, the difference is typically within 2% to 5%.

  (Click on image to enlarge it)

Graph Analyze -  Find Difference Between Lobes

If you graph 2 cams, an Analyze option is available called Find Difference Between Lobes.  This option will automatically advance or retard each corresponding lobe of the second cam to obtain the best match, and then display the max difference between the lobes and how much advance and retard was required.  If you have graphed Lift, then the best match for Lift will be found and the max difference in Lift will be displayed.  If Velocity and Acceleration are graphed, then the best match for both Velocity and Acceleration will be found and the max difference in Velocity and Acceleration will be displayed.  

This feature is very useful for finding how a particular cam has changed after running in the engine, if a cam is within legal specs for some racing class, or how similar 2 different cams are.  Click here to see a typical "Find Difference Between Lobes" report for Lobe Lift only for all 16 lobes.  Click here for a comparison of only 2 lobes, #1 Intake and Exhaust Lobe Lift and Acceleration. 

Indexing the Rotary Encoder

When you measure a cam on the Cam Test Stand, you must choose where the #1 Intake cylinder's lobe will be installed in the engine, typically based on Intake Lobe Centerline.  All cam data is accurately measured (duration, lobe separation, lift, overlap, accelerations, etc) and the differences between lobes are identified.  However, you would not know if the cam would get installed at this Intake Centerline unless you verified it in the engine.

Now we can measure the dowel pin or keyway location of a cam and know how it is timed in the engine, assuming standard, production timing in the gears.  Using our TDC Checking Bridge, we can precisely measure the dowel pin or keyway location.  Then, knowing how many degrees CW or CCW from TDC it is designed to be, we can index the rotary encoder precisely.  Using this method we can index the cam to better than 0.5 degrees.  (We can provide the "degrees CW or CCW from TDC" data required for this method for many popular engines, but not all engines.)  For engines for which we don't have this data, you may have to work out these settings from known cams.
  (Click on images to enlarge them)

The TDC Checking Bridge is sold as an accessory, and adjusts to most any length cam from 12 inches to 24 inches in length (measured from first and last journal bearings).  However, you do need the Plus version of the software to access this feature.  Longer Bridges are available at an additional cost.

Other Plus Features

The Cam Card report displays critical, measured cam results commonly found on a cam grinder's cam card, shown below:
  (Click on image to enlarge it)

Asymmetry Calculation:

More Report Types:

Click here for: Custom Duration (duration, opening, closing, asymmetry at most any cam or valve lift)

Click here for: Seating Velocity (valve closing velocity at user specified RPMs to help pick valve lash)

Click here for: Checking Limits (compare a measured lobe to up to 12 specified limits, like duration at various lifts, lobe separation, max lift, etc.)  "Checking Limits" report makes it quick and easy to check if cams are legal for restricted classes of racing, or are meeting certain quality control limits. 

*  Lifter bore sleeve is bored to user's requirements for their lifter size.  Additional Lifter bore sleeves for different size lifters available at additional cost.

Accessories:

  Part Number: CTS-ML  Locating magnet, keeps cam aligned accurately on V blocks.  Flip down and its out of the way.  Flip up and it keeps cam turning true on the stand.  Magnet slides out of the way if it encounters a dowel pin.  Kit includes magnet, shoulder screw, washer, nylon spacer, template for locating 6-32 hole you drill and tap, and instructions.  Click here for instructions.

  Part Number: CTSUR750  Universal .750" roller follower, lets you measure any cam designed for a .750" diameter roller (typical of most, US V-8 aftermarket rollers).  Sized for a GM .842" ID lifter bore adapter, this includes the follower only and not the lifter bore adapter.

  Part Number: CTS-LEH  Linear Encoder lift handle, provides an easy way to lift the linear encoder probe.  This is especially handy when not using a follower, but measuring the lobe directly for the Virtual Follower feature.

  Part Number:  CTS-TDCB  TDC Checking Bridge provides a precise way to measure dowel pin or keyway location of you cam.  Bridge comes with magnetic "dowel pin" for keyways.  Longer length bridges are available at an extra charge.  This allows the program to predict installed timing using standard "factory" timing gears and timing marks.  (Note:  Factory settings are not known for all possible cams.  You may have to obtain this information for less common cams.)

Click here for Demo Movie file to see the TDC Checking Bridge in action.

Ask about other custom options which include:

Click here to return to the main Cam Analyzer page.

Click here for prices of the Cam Test Stand and accessories.

Click here for Demo Movie files to see the Cam Test Stand in action.

Click here for info on Cam Test Stand Assembly

Click here for tips on producing repeatable results