Crankcase and cylinder head,  OM617

Measuring, boring and honing cylinder bores

 

 
01—110 Measuring, boring and honing cylinder bores

 
Coordination piston — cylinder

 
Version l)
Group no.
Piston dia.
Cylinder dia.
Standard
0 1 2
90.845 – 90.855 above 90.855 – 90.865 above 90.865-90.875
90.898 – 90.908 above 90.908-90.918 above 90.918-90.928

 
Cylinder bore

 
Max. wear limit in forward or transverse direction
0.10

 
when new
0.014

 
Permissible out-of-true and conicity

 
wear limit
0.05

 
Permissible deviation vertically in relation to crankshaft center line, with reference to cylinder height
0.05

 
Permissible roughness
0.002-0.004

 
Permissible waviness
50 % of roughness

 
Honing angle
25C

 
Chamfer of cylinder bores
refer to Fig.

 
1 These engines have no repair steps.

 
Note

 
In addition of a visual checkup, in particular in the event of complaints about “high oil consumption” measuring of cylinder bores is unavoidable.

 
For this purpose, measure the clean cylinder bores with internal measuring instrument at measuring points, 1, 2 and 3 in longitudinal direction A (piston pin center line) and in transverse direction B.
With piston installed, the measuring point 3 is barely above piston, at BDC.
om617 - 0029-1.jpg
a Upper reversing point of 1st piston ring
b BDC of piston
c Lower reversing point of oil scraper ring

 
01.8-110/1 F2

 

 

 
Chamfer cylinder bores after boring.
For honing, the material allowance should not exceed 0.03 mm.
om617 - 0030-1.jpg

 
01.8-110/2 F2