MakerBot Print is our newest print-prepration software, which supports native CAD files and STL assemblies,
allows you to interact with all your printers via the Cloud, and many other exciting new features.
sounds like you really did lots of R&D thinking this through. yes earlier visible engine models also opted for timing gears for best operation. I built both the Renwal V8 and the Revell version which had a better mount for distributor so it didnt wobble off angled gears. as for bearings I smoothed all points of friction so fine that all I had to do is add a bit of mineral oil to the areas and the whole thing could be spun with fingers very easy. thats what must be done for display models like this. and when 3D printed in ABS (which is way better than the Styrene of the 1960s lol) you can acetone vapor parts smooth and shiny. I will PM you me email and we can communicate easier on these subjects. I have 50 years experience that can be tapped for bouncing ideas off of. the revell V8 1st version used a starter motor to turn everything from flywheel and a 'batter' box with wires passing through a switch to turn on motor and spark plug lights. looked like real ones and nobody could tell.
I agree easier design programs and creating good printable files is the next hurdle needing tackled, as the printers are getting near industrial quality now for home use.