The JSRE TDC Measurement Gauge
By Greg Terzian

As a Scream And Fly reader, you’re probably no stranger to the inner workings of your outboard motor.  Even if you are, you’ll most likely eventually experience the satisfaction and pride of working on your engine yourself. 

As with any such undertaking, one of the most important factors to help guarantee success is the proper tools.  Inaccurate and clumsy tools cannot only make a job unpleasant; it can cause engine damage, or even worse – personal injury.

Left:  The JSRE TDC measurement tool. Right: Will work with standard and O-ring type heads.

One procedure that could benefit from an accurate tool is measuring the top dead center of a piston in the cylinder. This is a crucial measurement that is required when indexing timing marks correctly in degrees.  There are many contraptions available of questionable functionality that are often used for this task.  Most of these measuring devices are home made, and as a result, may not be accurate.  Not only that, they are not readily available.

Jay Smith Racing Engines makes a foray into this field with their new, custom Top Dead Center tool.  It’s a high quality machined piece that threads into the head, and requires no special tools or adapters to install.  Measurements are easy and accurate with the large precision movement.  At only $40, it’s a bargain, too.  The tool will work in standard or O-ringed heads, and also accepts standard plug threads, however, custom threads can be made to order.