---
kind: "section"
citation: "40 C.F.R. § 205.153"
title: "40"
number: "205.153"
heading: "Engine displacement."
url: "https://uscodex.org/cfr/40/205.153"
---

# §205.153. Engine displacement.

- (a) Engine displacement must be calculated using nominal engine values and rounded to the nearest whole cubic centimeter, in accordance with American Society for Testing Materials (ASTM) E 29-67.
- (b) For rotary engines, displacement means the maximum volume of a combustion chamber between two rotor tip seals minus the minimum volume of that combustion chamber between those two rotor seals times three times the number of rotors.

## Notes

### Source

Source: 45 FR 86708, Dec. 31, 1980, unless otherwise noted.

### Authority

Authority: Secs. 6, 10, 11, 13, Pub. L. 92-574, 86 Stat. 1234 (42 U.S.C. 4905, 4909, 4910, 4912).

### Source

Source: 41 FR 15544, Apr. 13, 1976, unless otherwise noted.