Federal MK1 pistons - keep or throw away?

[Ian928]

We are dismantling and preserving a spare engine we have bought. I am not sure if I should keep the pistons, are there any reason to keep them vs what is available today? The skirts are worn on one side. They are flat.731C9DB5-BF4A-4CB9-973B-8BAAAFA99AC8.jpeg

[trunt]

There are 2 versions of federal pistons, early with a slight dish 8.8 CR basically the same as U.K. MK1 and later (72/3) with a deeper dish with a CR of 8.0 mk1 7.75 mk2

If they are the earlier ones then they can be used, TBH wouldn’t bother with the later ones..

Terry

[mole42]

Personally, I would keep them. I would clean them, measure the diameters at 90° around the skirt, measure the ring gaps, measure the gudgeon pin holes. After which I’d re-assess my decision.....

[jbuckl]

Personally, I would keep them. I would clean them, measure the diameters at 90° around the skirt, measure the ring gaps, measure the gudgeon pin holes. After which I’d re-assess my decision.....

+1 for that, measure & then decide.

[Ian928]

Thank you, I will measure then decide. BUT what to measure? Are there any tolerances for pistons in the WSM? Or do I just compare them to each other?