Jeff, Those steel bits are expansion control struts .... and are an integral part of the piston design. They physically limit/control the expansion rate of the pistons. Removing them would be a disaster ..... as they also add to the strength of the piston around the pin area.When comparing them to see why, I see the Opel slugs have some steel imbedded in the skirts beside the pin bosses. The Venolias don't.
Why is this steel in there, and can it be removed? It doesn't appear to be cast in, looks like they are just tabbed and "snapped" in maybe.
I see some extra aluminum all over the piston that could be cleaned up, this could make it a little lighter, but those steel things would be major weight as opposed to none!
What would happen if you decked the block, then milled the same amount off the top of the pistons? Then redrilled the cam sprocket to correct the cam timing.
What is your reason to deck the block? Is it warped, pitted or are you looking for a compression increase?What would happen if you decked the block, then milled the same amount off the top of the pistons? Then redrilled the cam sprocket to correct the cam timing.
My only experience with cutting stock pistons, was with our home-grown stroker motors. We welded up the rod throws on the crank and off-set ground the crank to increase the stroke .250. We used low compression pistons and cut the tops .125 which made them flat tops with valve reliefs. It moves the top ring .125 closer to the piston top, but we seen no adverse effect by do that. We built 8 or 10 of those motors and they all ran several years without a problem. The cams we ran were about .430 true lift (with 1:44 stock rockers) and we had no interference or problems with spark knock. If you angle mill the head instead of flat cutting it you have less problem with timing chain slack, and it can be made up with a longer piston on the chain tensioner. By angle milling the head it tiles the ports upward and allow a more direct shot from the intake manifold to the valves. Angle milling is the most effective way to reduce combustion chamber cc's and increase compression.Jeff wants to have lighter pistons. So if you take say .050 off the block deck and .050 off the pistons, the compression ratio will stay the same. Nothing will change with piston to head or piston to valve clearance. CID will not change. Cam timing will be changed so it will need corrected. Jeff said he wanted wild ideas.
Jeff the pistons from the A400 are "stock OEM",Come to think of it, the meaning of "stock" is sometimes construed as "stock replacement", it doesn't necessarily mean it has to be an OEM part.