Where Do I Measure 2.0 94mm Mahle Pistons? Options

[DBF]

I want to check my pistons before I just buy new ones. There is no scoring, and the ring lands measure well within spec, but I cannot find information on where to measure the piston diameter. If it's like other Mahle pistons, I know you have to measure "X" distance from the skirt. Is that true for the stock 94mm Mahle pistons? If so, anyone know how far from the skirt?

Thanks!

[Dave_Darling]

The Factory manual specifies measuring at the bottom edge of the piston skirt. It lists a table with a couple of oversizes on the 1.7, only standard size on the 1.8, and the 2.0 table seems to have been published incomplete without the size data in it!

The 1.7 piston sizes have three tolerance groups within each size.

1.7: 90mm cylinder nominal
Standard:
Blue tolerance, Cylinder 89.990 - 89.999; piston 89.95mm
Pink tolerance, Cylinder 90.000 - 90.009; piston 89.96mm
Green tolerance, Cylinder 90.010 - 90.019; piston 89.97mm

First oversize:
Blue, cyl 90.490 - 90.499; piston 90.45mm
Pink, cyl 90.500 - 90.509; piston 90.46mm
Green, cyl 90.510 - 90.520; piston 90.47mm

Second oversize:
Blue, cyl 90.990 - 90.999; piston 90.95mm
Pink, cyl 91.000 - 91.009; piston 90.96mm
Green, cyl 90.010 - 91.020; piston 90.97mm


The 1.8 table only shows the standard size, with only two tolerance groups shown.

1.8 liter engine, 93mm nominal:
Standard size:
Blue, cyl 92.992 - 93.008; piston 92.97mm
Pink, cyl 93.002 - 93.108; piston 92.98mm


The 2.0 table has entries for two oversize groups, but all of the entries are blank. It notes that the nominal cylinder size is 94mm, but we already knew that.



There may be more information in the Little Spec Book, but I don't have access to my copy at the moment.

--DD