Hawkeye Scope: A Bird’s Eye View of Your Pistons


Ever wish you could see what the parts inside your engines combustion chamber look like? Now you can with the Hawkeye borescope.

Whenever you mention borescopes, people immediately think of one of those $3,000 units that only high-end shops can afford to have in the tool cabinet. Not any longer. The folks at Gradient Lens Corporation have come up with an excellent borescope thats within the reach of mere home mechanics and others who like to tinker with machinery. This is especially helpful to owners of high horsepower two-stroke engines. Now they can inspect the condition of the cylinder wall for any signs of piston ring-to-cylinder wall distress and have the problem remedied before catastrophic failure occurs.

The Hawkeye Slim and Hawkeye Hardy are two focusing borescopes that make use of the same technology as Gradient Lens medical units. In fact, the Slim is actually designed to check gun barrel bores. The Slim has a diameter of 0.165″ (or about 11/64″/4.2 mm), while the Hardy has a 0.250″ (or about 1/4″/6.35 mm) diameter to accommodate a larger mirror. (More about the mirror in a moment.) The diameter of the Slim with the adapter attached is .191″ (or about 3/16″/4.85 mm). The Hardys diameter is .280″ (or about 9/32″/7.2 mm).

To keep the cost of the units down, the Hawkeye uses a common Mini-Maglite flashlight as its light source. The Mini-Maglite provides sufficient light, and a 10-year-old can change the flashlights two AA batteries or bulb. As for the optics, both Hawkeye versions use glass rods to transfer the images and light through their tubes. This also helps to lower the cost of the units while maintaining high-quality optics.

We tried both versions of the Hawkeye. The Slim and Hardy both provide an excellent view of the cylinder bore and the top of the piston. Being thin enough to slip into the cylinder through the spark plug hole, the tool can also be used to inspect the plug threads on the way in. Once its inside, you simply move the borescope around to view most of the cylinders wall and the top of the piston. (Be careful not to jam the borescopes tube against anything or in the plug hole. This will break the glass rod in the tube and make the scope useless.) To see the underside of the cylinder head and the upper end of the cylinders walls (or on some engines, the cylinder wall on the same side as the spark plug), a 90 adapter must be slipped onto the tube of the Hawkeye. Simply rotating the adapter on the Hawkeyes tube gives the user a 360 view around the tube.

This feature works very well but not as well as viewing straight ahead. Both the Slim and Hardy sometimes gave us a confusing image when using the 90 adapter. However, this is not due to inferior optics; rather, its because the user can see the image in the adapters mirror and the view around the perimeter of the mirror. The Hardy has less of this double image than the Slim due to its larger mirror (which is why it was designed). However, this double image is something the user can get used to filtering out after practicing with the adapter. Its still a lot easier than removing the head to inspect the cylinders bore, piston top, and head. It can also be bought without the 90 adapter.

As for the quality of the optics, the images are crystal clear-or all you could ask for in a boroscope. When viewing straight ahead, the Hawkeye is set to focus on objects 1″ to 2″ from its lens. The user can clearly see the cylinders cross-hatch or any marks or scratches in the cylinder wall. The pistons dome is also clearly visible as are the spark plug threads (as we mentioned).

The focus on the adapter is adjusted by simply sliding the adapter on the Hawkeyes tube. The user can see the combustion chamber, and for four-stroke owners, the condition of the valve and valve seat. (Note: To view the valves entire seat face, you must rotate the valve.) And although there are two separate images visible when using the adapter (the view straight ahead and the adapters), the adapters image can be brought into sharp focus.

We recommend the Hawkeye to anyone who needs to see whats happening inside their engine, whether its a two- or four-stroke. If you own more than one piston-driven machine, the Hawkeye Hardy is probably the unit for you. Gun owners would be foolish to overlook the advantages of a borescope that will also fit their guns bore. For them, the diameter of the Slim or Hardy would be the deciding factor in our opinion. Both the Slim and Hardy are available in three different lengths-7″, 12″, and 17″.

The Hawkeye comes with a one-year warranty and a guide that explains how to correctly use and properly care for the device. The 7″ Slim retails for $399, while the adapter retails for $95. The 7″ Hardy retails for $444, the adapter for $105. (Gradient Lens Corporation, 207 Tremont St., Rochester, NY 14606; 716/235-2620, or (fax) 716/235-6645.)

Instrument Hoods
The marine market isn’t huge. It isn’t even large. Therefore, much of what sailors enjoy in the way of new products are spin-offs from big-volume endeavors that can afford the research and development. For instance, if it were not for automobile tires, we wouldnt have nylon line; if it wasnt for the military, we wouldnt have navigation by satellite, etc.

This is not to say that theres nothing new thats inimically marine. Lots of new products are the result of individual sailors looking for better ways to do things. Practical Sailor readers know that anyone willing to try gets a good audience in this magazine.

Note now a new company called North American Opti-Shade. Fancy handle, but its really two sailors-John Barker and Duane Thomas-who discovered a market for hoods for marine instruments. Duane, a retired advertising executive, does the paperwork. John makes the hoods. He buys 4′ x 8′ sheets of a very unusual material called Sintra, which is a closed cell foam PVC that comes in thicknesses from 1 mm to 19 mm and many colors. It cuts easily, can be milled and routed, glued, drilled, bolted and is resistant to most everything harmful. The Sintra is quite stiff and has a good finished edge. Cut into blanks and then routed to shape to fit wood patterns, the stuff then is heated and placed in a bending jig. Apply some 3/4″ genuine sticky-backed Velcro and you have a good-looking hood.

The good part, John said, is that if we don’t stock em; its easy to cut one custom. There are lots of old instruments that never came with hoods or the hoods have been lost and are no longer available. We already have about 250 patterns in stock, for depth sounders, radar, plotters, loran, compasses, engine and sailing instruments-you name it, no problem. Any color, round or square, no matter.

John said the flat black hoods seem most popular, but if the instrument is in open sunlight, he recommends a lighter color, with white being best.

Fitting the hoods is easy. The kit includes a strip of Velcro and a small alcohol wipe to make sure the adhesive gets a good take. After mounting, they can, of course, be installed or removed at will. For flush-mounted instruments, it would be fairly easy to make and install a 3/4″ wood frame on which to mount the hood.

The hoods sell for anywhere from $9.95 for an Apelco handheld GPS to $34.95 for a Simrad Shipmate RS2400 GPS Chart Plotter. For small instruments, they range from $9.95 for the Autohelm ST-30 to $16.95 for a KVH Quadro-2 Supertwist Maxi. Compass versions are from $9.95 for the Ritchie Explorer series to $18.95 for a Globemaster. (North American Opti-Shade, 1000 S. Woodward Ave., Birmingham, MI 48009-6734; 248/258-7799, fax 313/533-5774.)

Darrell Nicholson
Practical Sailor has been independently testing and reporting on sailboats and sailing gear for more than 50 years. Supported entirely by subscribers, Practical Sailor accepts no advertising. Its independent tests are carried out by experienced sailors and marine industry professionals dedicated to providing objective evaluation and reporting about boats, gear, and the skills required to cross oceans. Practical Sailor is edited by Darrell Nicholson, a long-time liveaboard sailor and trans-Pacific cruiser who has been director of Belvoir Media Group's marine division since 2005. He holds a U.S. Coast Guard 100-ton Master license, has logged tens of thousands of miles in three oceans, and has skippered everything from pilot boats to day charter cats. His weekly blog Inside Practical Sailor offers an inside look at current research and gear tests at Practical Sailor, while his award-winning column,"Rhumb Lines," tracks boating trends and reflects upon the sailing life. He sails a Sparkman & Stephens-designed Yankee 30 out of St. Petersburg, Florida. You can reach him at darrellnicholson.com.