Tool Q&A: Using inspection tools

Cappert covers questions borescopes, fuel pressure testing, vacuum pumps and more

The growing complexity of technology in today's vehicles continues to drive the need for solutions to diagnostic and repair challenges you face every day. In this issue, we'll address questions PTEN readers have submitted about inspection tools, including some of the tools used to perform diagnosis in certain systems.


Q: When comparison shopping video borescopes, one model has a larger screen with lower resolution than another model with a smaller screen and higher resolution. I’m confused as to which would be the better choice.

A: As is the case with computer displays, the higher the resolution, the clearer the image detail—at least in theory. Higher resolution displays yield more electronic “dots,” known as pixels, which should reveal more details in the image you see. However, there are some variables in play here.

For one, a display can’t reveal details any better than what’s taken through the probe end, the “camera” of a video borescope. Second, depending on the quality of the imaging technology within the borescope, and the lighting adjacent to the probe’s end, the quality of the image conveyed to the display may not take advantage of a higher resolution display. Some borescopes may display images that are more “grainy” in low-light conditions than others.

So, although specifications are something to brag about and admire as a “techie,” your best bet is to test drive the borescope you’re considering to see if it produces the details you’d like. Use this approach for more than just the visual display on the screen. Also compare captured images and video between models, so you’re making a thorough comparison. Remember, you’re going to count on this device day-in and day-out to make good judgments on repair scenarios. Don’t cheat yourself by making a shallow judgment on tool performance.

Q: Some of the work we do calls for the use of a dial indicator. How does this differ from a micrometer and are there other needs for a dial indicator other than engine work?

A: Typically you use a micrometer to take precision measurements of components, such as pistons, brake rotors and others and then compare the measurements to specifications. A dial indicator, on the other hand, becomes the tool of choice when looking for measured variations to see if the variations are within specifications. When using a dial indicator, the part being measured must move so the indicator’s plunger can “feel” any variations in the part.

For example, you’d use a dial indicator setup on a camshaft to measure the height (lift) of camshaft lobes. As another example, a dial indicator is the solution for checking disc brake rotors for run-out (wobble). With the dial indicator in place, you rotate the rotor while observing the indicator’s dial for variations, representing run-out. You then compare your readings to published specifications in a reliable shop manual.

Q: We’re considering a borescope for our shop, but we’re not sure what to look for. Any tips?

A: In recent years, borescopes have emerged as one of the best investments you can make in an inspection tool. As features for these tools have increased, prices have come down, making them an excellent value. Although rigid borescopes with a fixed eyepiece still have purpose, your best value in borescopes is the video borescope. Harnessing the latest technology, video borescopes empower you to use this tool in more applications than ever before. Today’s models feature lit, flexible probes in various lengths, with the ability to not only view things you inspect, but also to record what you see. For instance, you can capture digital images for archiving with customer work orders, or even capture video that can be used to help sell a given job.

Q: What can we do to make sure the borescope we choose is not right just for today, but also out into the future?

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