Due to diameter limit of diesel engine injector holes, there are not many videoscopes / borescopes can be used for diesel engines, especially articulating borescopes. Now we have several 180 degree articulating borescopes with small diameter (less than 6mm) probe camera. They are suitable for diesel engine borescope inspection. 

The affordable versions are USB articulating borescopes (model D3160 and D3145). They can be connected to a PC, laptop, mac, chromebook, or Android tablet or phone. With our wifi wireless adaptor, AirBox, they can be used with your own iPhone or iPad. ​ME-610 is a fully articulating borescope with joystick control. The diameter of probe camera is 6mm and length is 1 meter. The camera can be bended back completely to 180 degree, and can be turned around 360 degree. 
Above are some pictures taken with Vividia D3145 inside a diesel duramax engine

Diesel Engine Borescopes

Vividia D3145 USB Digital 180 Degree One-Way Articulating Borescope with 4.5mm diameter 1 meter long Camera Probe
$949.98
$949.98
Vividia D3145 USB Digital 180 Degree One-Way Articulating Borescope with 4.5mm diameter 1 meter long Camera Probe (Demo Unit)
$949.98
$800.00
Vividia D3245 USB Digital 2-Way Articulating Borescope with 4.5mm diameter 1.5 meter long Camera Probe
$1,399.98
$1,399.98
Vividia D3160 USB Digital 180 Degree One-Way Articulating Borescope with 5.9mm diameter 1 meter long Camera Probe
$799.98
$599.98
Vividia ME-610 Industrial Automotive Videoscope Borescope Inspection Camera with Detachable 6mm x 1m Joystick-Controlled 360 Articulating Probe
$1,299.98
$1,299.98
Vividia ME-610 Industrial Automotive Videoscope Borescope Inspection Camera with Detachable 6mm x 1m Joystick-Controlled 360 Articulating Probe (Demo Unit)
$890.00
$890.00
Vividia VA-4-55 Four-Way Articulating 5.5mm Diameter 1.5meter Videoscope Borescope Inspection Camera
$3,499.98 - $3,999.98
$3,499.98 - $3,999.98
Vividia VA-2-39 Two-Way Articulating 3.9mm Diameter Videoscope Borescope Inspection Camera
$3,999.98 - $4,499.98
$3,999.98 - $4,499.98
Vividia VA-4-39 Four-Way Articulating 3.9mm Diameter Long Videoscope Borescope Inspection Camera
$4,499.98 - $5,999.98
$4,499.98 - $5,999.98
Vividia VA-2-28 Two-Way Articulating 2.8mm Diameter Videoscope Borescope Inspection Camera
$7,999.98 - $8,499.98
$7,999.98 - $8,499.98
Vividia VA-4-28 Four-Way Articulating 2.8mm Diameter Videoscope Borescope Inspection Camera
$8,999.98 - $9,499.98
$8,999.98 - $9,499.98
Vividia VA-4-2010 Four-Way Articulating 2mm Diameter 1.1 Meter Long Videoscope Borescope Inspection Camera
$11,999.98
$9,995.00
Vividia ET-39 Industrial Motorized Joystick-Controlled 360 Degree Articulating Borescope Videoscope with 5" LCD Touch Screen
$8,999.00 - $9,999.00
$8,999.00 - $9,999.00
Vividia VT-2-2410 Video 2-Way Articulating Borescope with 2.4mm Diameter Probe and 4.3" LCD Monitor
$12,000.00
$9,990.00
Vividia GP-2-2410 Video 2-Way Articulating Borescope with 2.4mm Diameter Probe and 5" LCD Monitor
$12,000.00
$9,990.00