Measurement Device

Over the years, we have developed The Engine Analysis Software and the limiting factor was ALWAYS the difficulty of measuring all the dimensions super accurately.

Bill McGraw developed a device to measure the head clearance accurately, and that was incorporated into our measurement system at that time. That worked for us, along with dial calipers and a high intensity light to see when the ports closed. One-day, Norris Sparks, our Dyno machinist and part of our development group decided that the measurement system was not as accurate as he wanted. SO…he came up with a different approach. He, being a machinist, knew that a height gauge would be ideal IF a system could be developed to be able to measure the port heights in a liner. He decided that the way to do it was to make a stem that would accurately snag the port. Following is the height gauge with the special stem installed. Following is the stem, highlighted for clarity.

STEM NOT INCLUDED WITH DEPTH GAUGE !

Using this system, we were able to get accuracy to 1/2 thousandth. That was fantastic! Better than that, we were able to measure a complete engine and document it into The Engine Analysis Software in less than 5 minutes with +/- 1/2 thousandth accuracy. We have found additional uses for the depth gauge. We measure the TDC position of the engine with the liner installed, the head projection, top of liner/top of piston difference, etc.

This depth gauge can be purchased from any machine supply store for about $500. Norris has found it as an import at Precision Industrial Tool & Supply, Inc. (800-433-7487) for $149.00. It is 12" model #EHG-605 The pin is an EX4 hard pin with a ground flat area of about .015"

Other notes for EAP Registered Users:

Brian Callahan and I have developed a little auxiliary spreadsheet program to calculate the exhaust port area. This is an input item in the newest version of EAP for calculating the ideal tuned pipe. If you would like this little program you may download it from http://rcboat.com/exhport.zip

Other images that may spur your imagination are located at http://rcboat.com/liner.gif and http://rcboat.com/nrpiston.gif and http://rcboat.com/osmixture.gif

This technical notes paper is dedicated to Ken from Ashville, NC. (probably not useful to him!)

Be sure to visit our new site for Ceramic Bearings for your RC Applications at http://rcboat.com