Proper piston ring gap measurement.

[JerseyDrew77]

Ok, so I am trying to find the proper piston ring gap for the top and second rings because I'm getting answers that are different from one another. The picture below are the instructions that came with my MAHLE Power Pack pistons but then when I called MAHLE and spoke to one of their technicians, I got a different answer. I went with the stock bore size (82.5mm) for my pistons and was told to go with the Circle Track, Drag Racing specs which are Top Ring - 82.5 x 0.0050 = 0.4125; Second Ring - 82.5 x 0.0060 = 0.495. Now the tech that I spoke to yesterday gave me these measurements for the Top Ring = 18 - 20 thousandths of an inch (0.018 - 0.020); Second Ring = 20 - 24 thousandths of an inch (0.020 - 0.024). So what is it???

 

[ChrisMk77]

Stock bore in inches would be about 3.248 x 0.0050 = 0.016" and 0.0060 would be 0.0195".

Full send on E85 you probably want a bit more.

 

[JerseyDrew77]

Stock bore in inches would be about 3.248 x 0.0050 = 0.016" and 0.0060 would be 0.0195".

Full send on E85 you probably want a bit more.

Ahh, so that's where I messed it up. That makes sense now and it appears the MAHLE technician was right.

 

[neogeo]

Ahh, so that's where I messed it up. That makes sense now and it appears the MAHLE technician was right.

I was going to say it looks like you’ve mixed units. Convert mm to inches by dividing by 25.4.

 

[JerseyDrew77]

I was going to say it looks like you’ve mixed units. Convert mm to inches by dividing by 25.4.

True. Or just use Google for the converter.

https://www.google.com/search?q=mm+...2...8.171024908j0j15&sourceid=chrome&ie=UTF-8