well i got the case together - i'm surprised how everything is working out. it's a 3.2 short stroke with mahle pistons and cylinders. i installed a .5mm copper shim and the cylinder with piston to check what the deck ht is at - only about .65mm. i will add another .5mm shim to bring it up to 1.2mm. the case was from a 140k mile engine and needed a little machining so i was not surprised with the need for thicker shims.
i decided to solid model in the computer the cumbustion chamber, piston top and cylinder and use the software calculate the measurements for the compression ratio. i know the piston dome volume for the rsr 98mm pistons is 29.2cc, and my cad work actually matched this so i feel fairly confident about the volume measurements. i did not model the exact profile of the valve seat and spark plugs but the approximation is fairly close. the heads are twin plug and the groove for the sealing ring was fly cut off and a larger chamfer added so the cc measurement ended up being 77.5cc, not the usual 90cc for sc heads. this worried me, i was told the pistons were 9.5:1cr but they look like the rsr type with 10.2:1 cr. after calculating the deck ht the cr ended up being 10.16:1. if i increase the deck ht to 1.5mm the cr drops to 9.9:1. it looks like i lucked out, usually when you buy parts from different people they rarely go together the way you think. i'm trying not to get to excited - there must be a problem ahead!
-matt
