Mahle Pistons the same size?

[Yehoshua]

When you buy after market mahle pistons for the 6.5, are they all the same size? Or are the pistons a different size for the #7 and #8 cylinder?

[trbankii]

You can get oversized pistons for over bored cylinders, but all eight should be the same size.

[john8662]

They're all the same size for a set. So if you get a .020 (50mm) oversize, they're all the same size, all 8 of them.

The factory used select fit pistons which were about .0002" - .0003" difference in size (not even a whole thou .001"). So you'd see some cylinders (not just 7 & 8) with difference sized pistons.

When you rebuild a 6.5, you're almost always going to be boring the cylinders.

You measure your pistons about 1" from the bottom of the skirt, which is where the piston is the largest. Then you'll add how much clearance you want to run, refer to the service manual for piston to bore specifications.

Typically .0035 to .004" overall bore clearance.

On cylinders 7 & 8 (I do #6 as well on non-spray blocks) You add .0005" of clearance (yes half a thou).

So, cylinders 1-6 would be .004"
and cylinder 7 & 8 would be .0045"

[Yehoshua]

Thanks for the replies

[Robyn]

What John said