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Piston markings - what they tell you


jgerock
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WORK IN PROGRESS

I did a search but didn't find what I was looking for - so I found some very good information on the Mahle website (but you have to look). http://www.mahleclevite.com/

The original piston FAQ is good, but doesn't tell me everything when looking at the top of the piston (crown).

http://www.bmw2002faq.com/content/view/46/32/

Here is a "bathtub" Mahle piston I removed from my 72tii spare engine

pics12102010015.jpg

pics12102010018.jpg

pics12102010019.jpg

I knew that the brand was Mahle and the size was 89.47mm, but I wasn't sure about the other markings. The Mahle website contains a ton of useful information.

Based on this, my piston measures 89.47 mm diameter with a clearance between the piston skirt and cylinder bore of of 0.045mm.

Adding these two numbers together equals the I.D. of the cylinder= 89.515mm.

piston_markings.jpg

Mahlepistonorientation.jpg

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