Do you wonder why some of the racers always have engines that run consistent and you are searching for that special engine? The setup has much to do with ending that search. If you do not know what your engine is set at, how do you know what to do with it to make it work harder for you? Once you have the setup you want, it will work for most engines. Then you only have to take conditions into consideration. Remember, we are all using the same equipment and it is the setup of the engine and the airplanes that make the difference in equipment performance.

You must know where you are so that you will know where to go.

We will first set up to check the deck height.(the distance between the top of the piston and the top of the sleeve at TDC) The first thing you do is remove the head and remove the sleevet. Then place the sleeve-ring on the sleeve. You can remove the existing shims or leave them on for your first measurement. Put the sleeve back in the engine with the sleeve-ring installed. Next zero the meter by closing the caliper and pressing the zero button.

QKE-25 Digital Measuring tool complete kit

Liner with the .200" spacer ring installed

Open the digital caliber about an inch and place the anvil on the top of the sleeve. Hold the anvil tight on the top of the sleeve as in the picture. Then turn the engine over until the piston goes past top dead center. You can now read the deck height. The picture shows .3955. Remember we installed the .200 sleeve shim under the sleeve and have to mentally subtract that amount to determine the actual deck height. This deck height is .1955. At this point, you can add or remove sleeve shims to what ever deck height works for you. With this tool, you can repeat the engine numbers that work in your conditions from engine to engine. A thing to note is that you can repeat this step as many times as you want and the same numbers will repeat every time. This tool is very accurate.

If the deck height is where you want it, move to the next step. If not, add or remove sleeve shims to get it where you want it. When it is there, the repeat this step before measuring the head clearance.

Now that you have the deck height number, the head spacing (head spacing is the distance between the head face and the top of the piston at TOC) is simple. With the digital caliper still in the last reading position, (.3955) press the "zero" button to reset the caliper to (0.000). Next, hold the anvil of the caliper on the face of the head and extend the caliper until it is firmly pressing on the seating surface of the head. The photo shows the reading on this head. It is reading .2155. After we mentally subtract the .200 for the sleeve ring, our head spacing is .0155. Just add or subtract head shims to get the numbers that work in your racing conditions.

With head shim, head spacing reads .015

(After our mental math of minus .200)

Darrol Cady
360-903-3520

© Copyright 2007-2008 Darrol Cady All rights reserved.