what you need to know is here, copied from one of my older posts.
There are just a few things you need to look for when interchanging parts between all Novarossi type 12 engines. hopfully this will dispel some myths or inaccuracies that have been posted around the web.
Covers the following engines in rear exhaust design with the exception of the new RBV12.
The piston and sleeves and rods
will all interchange including the 5 port designs with this exception. The MT/REX 12 can accept all piston,sleeve assys but all the others (short rod)cannot accept the MT/REX piston sleeve and rod assy. the piston does not have a skirt or cutout and it will hit the crank. All novarossi's have 4.5 MM exhaust port heights and the physical timings are the same on the sleeves from model to model. MT/Rex engines use the long rod like a CX 12 side port
will all interchange including turbo assys but the head finset must follow the head button.
All carbs will interchange.
All bearings will interchange, the V12 is an exception here
All backplates will interchange
Crankcases will all interchange except the MT/REX 12 the case locates the liner higher because it has a longer rod.
All cranks will interchange. The timings can vary from the wide intake design and the narrow. The wide design pops up from time to time and is relatively new. The MS Novamega 12 has it as does the S3.
The V12 crank is an exception here it is all by itself
There is no long and short stroke Novarossi 12 crankshaft contrary to popular belief. Only a long and short version of the connecting rod and this has no effect on physical stroke.
All of them are 14 MM stroke/13 MM bore
There are variations of all these parts but generally the physical geometry is the same.
The side ports share parts with the MT/REX except one wierdo that was made by HPI (not the C12) that was a short rod side port
That's the jist of it
Just here to give the world grief.
Last edited by Motorman; 09-29-2003 at 02:52 PM.