ASTM D6618 Standard Test Method for Evaluation of Engine Oils in Diesel Four-Stroke Cycle Supercharged 1M-PC Single Cylinder Oil Test Engine
11. Inspection
11.1 Preparation - Use a clean, soft, dry cloth (for example, cotton outing flannel) free from any solvents or polishes, and wipe the test piston free of oil film.

11.2 Inspection - Inspect the piston and liner, and photograph the piston at the end of the test. Make a complete written description of the inspection. Remove all rings from the piston before it is photographed. Determine and record cylinder liner and piston ring wear. Inspect the piston, rings, and liner in accordance with the report forms shown in ASTM Deposit Rating Manual 20, with the following exceptions:
11.2.1 Use a Sylvania 8-in. circular bulb, 20 W, cool white, Part # FC8T9-CW-RS in the rating lamp.

11.2.2 Conduct routine maintenance, such as bulb replacement, fixture cleaning, and booth repainting, on a regular basis.

11.2.3 Have a probe available for use in identifying questionable carbon-like deposits.

11.2.4 Use the recommended 20-segment template to obtain maximum precision. Each segment, which represents a 5 % area, should not be broken down into areas smaller than 1 %.

11.2.5 Evaluate only three levels of carbon in the piston grooves. They are defined as follows: Heavy Carbon - Carbon that will take up the whole space between the back of the ring and the back of the groove and the lesser levels of carbon that exhibit polished areas due to an excessive amount of carbon on the back of the ring with relative ring movement. Medium Carbon - Carbon that will take up to between approximately one-quarter to just less than the whole space between the back of the ring and the back of the groove. Light Carbon - Carbon that will take up to approximately one-quarter of the space between the back of the ring and the back of the groove.

11.2.6 Evaluate only two levels of carbon on the ring lands. They are defined as follows: Heavy Carbon - Carbon that shows signs of rubbing or polishing, or both. Light Carbon - Any other carbon deposit.

11.2.7 For standardization of the interpretation of clean, keep a new piston in the rating booth for comparison. Replace this piston daily with another new piston, if possible.

11.3 Rater Training - Each lab shall send, on a calendar year basis, a minimum of one heavy duty diesel piston rater to either the Task Force meeting held every spring or expanded Heavy Duty Piston Rating Workshop held every fall. Each rater shall rate a minimum of six diesel pistons. If this schedule is not suitable to a particular rater or test lab, then alternative arrangements shall be made as soon as possible to have the rater calibrated.

11.4 Referee Ratings - To quickly detect and correct any shifts in rater severity, all operationally valid calibration tests shall be refereed. Obtain referee ratings only from another calibrated test lab. Wrap all pistons being shipped for referee ratings in paper, place in plastic with desiccant, and then seal before placing in any other shipping container.