The best advice that I can give a tech official is to stay active throughout the day. The easiest way to prevent a problem is to spot it before it becomes one at the end of the day. Whether I am helping in tech or representing Briggs & Stratton at a track I take the time to look over every engine that comes by me. From helping load a kart after a practice session to walking the pit lane as everyone stages, this is time well spent. "This fastener has to be stock, your exhaust needs to be wrapped completely, your carburetor overflow line has a low spot which could rob you of performance if it fills with fuel, and so on."
By showing a vested interest in helping racers you earn respect, appreciation, and most of all you save yourself from an unnecessary situation.
If the rules don’t say you can then you cannot. Most of us will agree as will the racer that this is not performance enhancing. In some cases rules are meant for simplicity and to control cost. While some fasteners can impact performance (an intake fastener used to change the alignment or air flow angle) to make rules on which can or cannot be used in what is a stock class defeats the intent. It adds unnecessary complexity and makes you have to sift through the can and can’t of fasteners.
When I find something like this doing visual checks in practice I will occasionally have a racer ask me if I would DQ them for this?
My response is simple, “Why put yourself in a DQ-able situation? If another competitor wants to point this out the rules are clear. I would suggest changing this out to prevent any chance of that from happening.” To add to my sincerity I might even throw in that I have one in my tool box if they need one. At this point we as tech officials have done everything we can to alert the racer to correct the action and the consequences. The racer is ultimately responsible to insure that their engine is compliant.
I had a national series call to say that they were having ‘all kinds’ of problems with the slide tech tools. The tech official told the principle owners that this was a ‘known’ Briggs problem. The conversation started off that some of the Sox tech tools were .001” and others were .002” oversized. I responded that .001” is the typical standard safety margin unless it is specified differently in the rule set so .002” would give each racer even more safety margin. That was quickly followed up by racers are using the tech tools to set their slide height and that the tech person decided to use a pin gauge AT the maximum opening. To that my reply was that a .570” plug gauge could legally go in. How was this communicated to the racers? Were the perils of using an inspection gauge for setting a part also talked about?
The takeaways to correct/resolve this issue:
'Compared to a known stock part' is the foundation from which any part can be compared. For example, while the width of the idle jet at the emulsion holes is not a call out the width or length from the threads to the tip can be measured using outside or a standard micrometer. The idle adjustor screw can be measured from the taper to the tip, overall length or from the thread to the tip compared to a known stock part.
I would suggest pre-measuring stock parts and have a written baseline. Give the racer the benefit of the doubt meaning a part that we measure as .001” different might be part manufacturing variance.
'As compared to a known stock part' is the biggest catch all that allows for additional inspection. With your performance hat on there are two areas where performance could be gained. The first would be increasing the reach of the spark plug to increase compression/improve the flame front. Comparing to a known stock part the reach of the plug can be checked using the depth extension on your micrometer.
Secondly someone might try to modify the internals of the plug by removing the resistor. Spark plug resistors help prevent electrical interference of radio, cell phone, and computer equipment. The 'R' of RC12YC stands for resistor. So having a radio next to the engine while its running is a crude but simple way to alert you. An OHM reading compared again to a known stock part will also give insight if further inspection is needed. A functioning plug will first give you a delay as it takes energy to flow through the resistor but will read UNDER 1,000 OHMs. If there is a question or a need for a deeper inspection the top cap at the high tension lead will unscrew with force. This will render the plug inoperable and a spark plug IF tampering is not found should be given to the racer. A part for a part.