I hope to help me in this.

I want to put the pistons in the cylinders and my engine is d16z but I have problem in gap size. The sizes which listed in the rings papers is .37mm for top rings and .45 for 2nd rings. My friend told to me to use .20mm. Which one of these sizes is best or if there is another size can any body advise me it will be great. Thanx.

I will show you how I calculate it :

Top Ring
bore mm / 25.4 = 75.5 / 25.4= 2.97
Bore" X 0.0055" = 2.97 X 0.0055 = 0.0148"
0.0148 X 25.4 = 0.3775 mm

2nd Ring
bore mm / 25.4 = 75.5 / 25.4= 2.97
Bore" X 0.0060" = 2.97 X 0.0060 = 0.0178"
0.0148 X 25.4 = 0.453 mm