View source for Pistons / Progressive Refinements

{| class="wikitable"
! Date Introduced !! Chassis No. !! Unit No. !! Modification
|-
! 14 Mar. 1950
| 1-0152 857 || 185 196 || only "KS" pistons with 0.035–0.055 mm clearance fitted from now on<ref name=":1">“Engine, Clutch, and Heating System” In ''Progressive Refinements 1940 - 1961'', [http://volks.wiki/oacdp/progref4061/m003.jpg M-5]</ref>
|-
! 30 May 1950
| || 199 321 || "Mahle Autothermik" pistons fitted in a number of cases<ref name=":2">“Engine, Clutch, and Heating System” In ''Progressive Refinements 1940 - 1961'', [http://volks.wiki/oacdp/progref4061/m003.jpg M-6]</ref>
|-
!6 July 1950
|1-0 173 141
|207 431
|"Mahle-Autothermik" pistons in a number of cases<ref name=":3">“Engine, Clutch, and Heating System” In ''Progressive Refinements 1940 - 1961'', [http://volks.wiki/oacdp/progref4061/m004.jpg M-7]</ref>
|-
!28 Aug. 1950
|1-0 188 291
|from&nbsp;255&nbsp;484<br>up&nbsp;to&nbsp;226&nbsp;410
|"Nüral" pistons, 75 mm dia. in a number of cases<ref name=":4">“Engine, Clutch, and Heating System” In ''Progressive Refinements 1940 - 1961'', [http://volks.wiki/oacdp/progref4061/m004.jpg M-8]</ref>
|-
!Dec. 1950
|1-0 218 140
|263 133
|20,000 "Nüral" pistons fitted<ref name=":4"></ref>
|}

== Notes ==

== References ==