Setting 2.1 deck with longer rod

[jackstraw]

Greetings. If I use a longer rod and want to measure how much to shave the tops of the piston(s), two questions come up. Maybe three.
Do I use the bottom sealing ring?
Do I need a torque plate?
Both?
Thanks,

[Piledriver]

Greetings. If I use a longer rod and want to measure how much to shave the tops, two questions come up. Maybe three.
Do I use the bottom sealing ring?

If still water cooled, use the oring unless you want a case full of antifreeze, strongly recommended.
If air cooled conversion or air/water cooled hybrid with T1 jugs and flat rings not unless you need it for a spacer.

Do I need a torque plate?

Not for pistons. Tencentliife showed how he did it, used a proper piston clamp, but there are other ways that work.
Note: Pistons aren't round, nor should they be, so generally you cannot simply pop them in a lathe.
(plus the long rod to get there, only the SCAT I beams have enough meat, really, available in several convenient lengths)

If you only need a little. think belt sander.

[jackstraw]

Thanks.
Yes, staying water cooled. Wasn't sure is the oring on the bottom of barrel would raise it slightly from seating unless a torque plate of sorts was used to push it down so as to mimic finished assembled height upon which then a true deck height could be measured and calculated.
Nothing too radical on the rod length. I believe a 5.5 rod will only push it out of the hole ~ 0.1.

I should have stated this is referring to a 2.1 DH

[Piledriver]

The oring lives in a groove, so you can leave it out for setting the height and put it in on final assembly.

Be careful with pistons hanging on rods w/o jugs as you assemble, or disassemble for that matter...

I picked up a core that was perfect in every way, except that someone had been rotating the crank and slammin the piston skirts against the block, and destroyed the block where the cylinder bases seal.
It wasn't incidental contact that cleaned up with a touch of Scotchbrite, the damage was too deep.