Machinist Balking at MB piston clearance specs

[Les Izmore]

I set out to rebuild my om617.95 engine last year, and its been to 3 machine shops now over the span of about 14 months. The first one got the head done but finally gave up on machining the block, the second one got nowhere and the place I have it at now is finally making progress, but the machinist is balking at the piston clearance of 0.043-0.063 mm.

It seems pretty clear from the 1992 FSM 03.8-316/1 that the piston to cylinder wall clearance is indeed 0.043 to 0.063 with the nominal clearance from the table being 0.053 mm (group 1 pistons fyi).

I did a quick search for ford powerstroke cylinder clearance is which is 0.11 mm (0.0045"), and since that is what the machinist drives, I can see his hesitation.

Am I reading the FSM correctly???

If memory serves I mic'd the pistons at about 90.1 mm, so it seems like the readily available 89.9 mm cylinder sleeves should be able to be bored out to accommodate them (which I hope is the case since they have already been installed.)

Any feedback on this is appreciated!!!