Pistons

Rigmover

New Member
Joined
Nov 6, 2020
Messages
6
Reaction score
0
Your Mercedes
GL320
Hello,

I've just stripped down my OM642 Diesel and am in the process of measuring and cleaning the pistons. The car is a GL320 with 220,000 kms

Ive separated the piston head from the con-rod,found this quite difficult as the only tools I had that were small enough to slip in to the groove on the piston to lift the clip would bend, in the end used a combination of small screw drivers. Is there a special tool for this operation?

To clean the pistons I soaked them in neat Simple Green - Purple, the majority of the carbon just brushed off with a toothbrush after a couple of days.

To the best of my knowledge this engine hasn't been dismantled since new but the piston rings do not match the style shown in the WIS. The top two rings are of different depths, 1.95mm (this ring has a partially readable number GOE 5) and 1.88mm, the cylinder wall contact edge are the same just a flat edge with a slight bevel, there doesn't appear to be an tapered face hook scraping ring as depicted by the WIS.

Does anyone know if this is normal.
 

Attachments

  • rings.PNG
    rings.PNG
    49.6 KB · Views: 17
  • DSC_0525.JPG
    DSC_0525.JPG
    192.2 KB · Views: 20
  • DSC_0528.JPG
    DSC_0528.JPG
    134.9 KB · Views: 19
  • DSC_0526.JPG
    DSC_0526.JPG
    153.6 KB · Views: 20
  • DSC_0527.JPG
    DSC_0527.JPG
    147.6 KB · Views: 17

LostKiwi

Senior Member
Joined
Aug 25, 2006
Messages
31,363
Reaction score
21,629
Location
Midlands / Charente-Maritime
Your Mercedes
'93 500SL-32, '01 W210 Estate E240 (RIP), 02 R230 SL500, 04 Smart Roadster Coupe, 11 R350CDi
It's quite possible the ring design was changed during a manufacturing run or a supplier changed and WIS not updated.
 

d:class automotive are specialists in automotive interiors and upholstery. From Mercedes and modern cars to custom and classics. Tel: 01483 722923 Email:info@dclass.co.ukWeb:www.dclass.co.uk
Top Bottom